Advancements and Applications of Wood-Based Sandwich Panels in Modern Construction

Abstract

Wood sandwich panels are widely utilized in residential, commercial, and industrial settings due to their excellent thermal insulation characteristics, ease of installation, and high strength-to-weight ratio. This review provides an overview on experimental outcomes demonstrating the structural integrity and versatility of wood sandwich panels. It highlights recent advancements in meeting payload requirements and their effectiveness in reducing costs and weights for prefabricated houses. The review focuses on structural applications and material efficiency, showcasing their roles in lightweight, durable constructions for retrofitting and new projects. The potential of novel, sustainable materials in construction is explored, addressing current challenges and emphasizing the diverse applications and environmental benefits of wood-based sandwich panels, underscoring their importance in advancing energy-efficient and sustainable construction.

1. Introduction

The global construction industry is currently facing two issues: first, meeting the growing requirements for residential buildings in the world, and second, minimizing its negative environmental impact. This situation emphasizes the importance of researching and implementing environmentally friendly building materials to help reduce carbon emissions, energy consumption, and construction waste. Wood-based sandwich panels are becoming increasingly popular as a building material due to their eco-friendliness and efficiency in the construction industry and other sectors.

Wood-based sandwich panels have improved significantly during the last few years. These panels were developed in the mid-20th century with the aim of providing lightweight, insulating alternatives for construction applications. Their capabilities have grown as material sciences and manufacturing technologies have advanced. Fundamental research in the late 20th century [1,2,3] helped explain the structural behaviours of sandwich panels under varied stresses. At the beginning of the 21st century, research increasingly focused on using more sustainable adhesives and core materials from recycled or renewable sources.

Wood-based sandwich panels are unique for their layered structure; thus, they have improved mechanical strength, good thermal insulation, and weight reduction [4]. It helps reduce transportation and construction costs. Also, using such renewable resources as wood corresponds with sustainable development goals, whose purpose is to prioritize and promote resource efficiency and lower greenhouse gas emissions [5,6,7,8].

Recent studies have highlighted the importance of materials used for the faces and cores of the sandwich panels and their geometric configurations in the determination of the thermal and mechanical behaviours of such panels. For instance, wood-based faces combined with various core materials like balsa (Ochroma pyramidale) wood and polyurethane (PUR) foam significantly influenced the panels’ performance [9,10,11]. The thermal performance of sandwich panels, governed mainly by the core materials, is crucial for effective insulation. Studies have reported the thermal conductivity (λ) values of foam cores as low as 0.070 W/mK, making them highly efficient for insulation [12,13]. Incorporating glass fibre-reinforced polymer (GFRP) in the faces of sandwich panels enhanced their resistance to bending and compression stresses, significantly improving the structural performance and longevity of the panels [10,14]. The mechanical properties of the panels could be further enhanced by optimizing geometric configurations, such as incorporating rib-stiffened cores, which increased load-bearing capacity and reduced the risk of buckling under stress [15,16].

Another critical aspect regarding the structural performance of sandwich panels goes to the connections between separate panels, between panels and structure, and between the panels’ layers. Effective connections are essential for ensuring the structural integrity and load transfer between panels in a building. Different types of connections, such as mechanical fasteners, adhesives, and hybrid systems, have been studied to optimize the performance and ease of assembly of sandwich panels [17,18,19]. For instance, it was demonstrated that the grooved bonding technique could enhance core–face adhesion in sandwich panels [20]. One study investigated the shear performance of a novel non-metallic cross-laminated timber (CLT) wall-to-wall connection using a double-dovetail mortise-tenon joint, demonstrating its effectiveness in enhancing structural integrity and load transfer, with the joint increasing the maximum load up to 47.27 kN and the maximum stiffness to 4.73 kN/mm [21]. Meanwhile, the ductility ratio, calculated as the displacement at the ultimate load divided by the displacement at the yield load, increased to 4.58 from 1.94 under cyclic loading, indicating its robust performance in seismic conditions. Another study introduced a novel hybrid joining insert for sandwich panels with pyramidal lattice truss cores, demonstrating improved shear performance and pull-out strength; specifically, the hybrid insert achieved pull-out loads from 2.10 kN up to 6.90 kN and a shear stiffness significantly higher than traditional inserts [22]. Integrating efficient connection systems between wood-based composite sandwich panels and load-bearing walls is essential for ensuring structural stability. Steel angles with adhesively bonded, bolted, or mixed connections significantly enhance the structural performances of panels with GFRP faces and either PUR foam or balsa wood cores, reducing mid-span deflections by up to 65%, highlighting their importance in building rehabilitation applications [23]. A deep understanding of the behaviours of these connections under different loading conditions is crucial for the safe and efficient use of sandwich panels in construction.

Sandwich panels are innovative products that have a significant impact on modern construction. Their applications include many construction projects, including residential and commercial buildings. They offer flexible options that meet the high standards of modern building design [4]. Furthermore, wood-based sandwich panels have natural aesthetic appeal and ecologically friendly characteristics. They help create environments that improve the well-being of residents and also make a connection with the natural environment [24]. It is a fact that studies have, during recent years and after the COVID-19 pandemic, found a positive correlation between the presence of wood in the built environment and its benefits for mental health [25,26,27,28].

Even though wood-based sandwich panels are becoming increasingly popular and offer numerous advantages, their implementation in the construction industry involves some challenges. It is necessary to conduct in-depth life cycle assessment (LCA) analyses to better understand their impact on the environment. Customer perception and cost competitiveness must also be studied [29,30]. In addition, ongoing research and innovation are necessary to address technological issues such as durability and fire resistance [31,32].

This review aims to achieve two primary goals. The first is to provide an overview of the current research on wood-based sandwich panels for construction, focusing on their development, properties, manufacturing techniques, and applications. The second is to identify current challenges and limitations preventing the uses of wood-based sandwich panels. This study also aims to collect information from the field and provide insights and recommendations for future research on wood-based sandwich panels in sustainable construction practices. This review is of interest to scientists, architects, engineers, policymakers, and consumers in both the wood and construction industries.

2. Definition, Composition, and Structure

A typical sandwich panel consists of two faces, two layers of adhesive, and a lightweight core of a unique structure (Figure 1).

Usually, the core of a wood-based sandwich panel comprises lightweight materials like foam, balsa wood, or other fibrous materials arranged in the structure of a given type [33,34,35,36]. The core sets the thickness of the panel; it may have lower stiffness and strength [3]. It is responsible for controlling the panel’s weight and limiting the relative movement of faces [36,37]. The face materials are usually made from engineered wood products like plywood, oriented strand board (OSB), or laminated veneer lumber (LVL), providing the structural strength and rigidity required for construction applications; see Figure 2 [8,11,38].

To further enhance the mechanical properties of wood-based sandwich panels, ribs can be incorporated into the core structure. Ribs, often made from materials like GFRP or other high-strength composites, significantly improve the stiffness and load-bearing capacity of the panels; see Figure 3. They also help distribute stresses evenly across the panel, reducing the likelihood of localized failures and increasing overall durability. Incorporating ribs can increase the flexural performance of panels. In non-wooden panels comprising a PUR core and GFRP skins, shear deformation of the core contributed to over 50% of mid-span deflection in the panel without ribs. By adding ribs, flexure became more dominant, and shear deformations of the ribs contributed to only 15–20% of the total deflection [15,16]. Another study on non-wood-based sandwich panels, composed of low-density PUR foam core sandwiched between two GFRP skins, has shown that incorporating ribs can lead to an increase in strength and stiffness by 140%, compared to non-stiffened panels [15].

Moreover, ribs and other reinforcements in wood-based sandwich panels could markedly enhance their flexural behaviour [12,15,16]. These reinforcements contributed to increased load distribution and resistance to local buckling. The introduction of ribs or webs could allow the use of lower-strength core materials while maintaining higher structural performance, making the panels both cost-effective and efficient for large-scale applications in construction [38,44].

3. Manufacturing Technologies

3.1. Fabrication

Wood-based sandwich panels are made through several steps, with the aim of making a final product with improved properties. Depending on the end-use application, it would be stable, lightweight, soundproof, fire resistant, and effectively insulating. Over the years, these manufacturing technologies have advanced significantly. Newer improvements have been focused on making the panels more efficient and environmentally friendly.

Traditional manufacturing processes involve the adhesive bonding of the core to wood-based facings. Hand lay-up is the fundamental stage where components are arranged by hand and prepared for pressing [45]. The final qualities of wood-based sandwich panels depend on the production method to some degree. The adhesive and pressing process affect the core–face bond strength, which impacts the mechanical strength and service longevity of panels [46]. Cold pressing is popular for its energy conservation; using room-temperature pressing with low-temperature curing adhesives increases manufacturing timelines by requiring extended curing periods [47,48,49]. In contrast, hot pressing uses heat to speed up adhesive drying, reducing production time. This heat increases the bond between the core and face materials but causes some energy consumption [45,50,51,52]. Vacuum pressing is a complex procedure that surrounds the panel assembly within a vacuum bag. It removes air before applying pressure, provides consistent pressure distribution, limits void formation, and increases the panel’s quality [53,54,55].

Recent advancements have been appearing following these traditional methods. They focus on improving the sustainability and efficiency of the manufacturing processes. For example, developing and applying eco-friendly adhesives focuses on bio-based compounds or the ones with reduced formaldehyde emissions. These measures have significantly decreased the panels’ environmental impact and improved indoor air quality in structures [56,57,58]. The development of automated assembly lines has resulted in a revolution in production efficiency. That can ensure stable panel quality, reduce material waste, and decrease manufacturing costs by optimizing the use of both materials and energy [59]. Furthermore, the precision provided by the 3D printing technology allows a core to be manufactured with complicated geometries, which provides specific advantages in thermal insulation or mechanical properties, thereby widening the potential for construction applications [60,61,62].

The comparative costs and economic analyses of different manufacturing technologies for wood-based sandwich panels reveal huge variations depending on the materials and processes used. Traditional manufacturing methods, such as manual lay-up and vacuum bagging, tend to have lower initial capital investment but higher labour costs [45,55]. In contrast, automated processes like resin transfer moulding and pultrusion, while requiring significant upfront investment in machinery and tooling, offer reduced labour costs and improved production efficiency in the long run [63,64]. Recent innovations in additive manufacturing and robotic assembly enhance cost-effectiveness by minimizing material waste and optimizing production times. An economic analysis indicates that automated and advanced manufacturing techniques, despite their higher initial setting costs, provide greater long-term savings and scalability, making them more suitable for large-scale production and industrial applications [65,66,67]. Decision-makers in the construction sector can leverage these insights to make informed choices about manufacturing technologies that balance cost, efficiency, and scalability. Furthermore, the life cycle cost (LCC) assessment can assist in understanding the costs of using wood-based sandwich panels in construction from cradle to grave.

There are several challenges in the production of wood-based lightweight panels, such as trade-offs between cost, labour intensity, limitations in finishing and post-forming, and performance degradation [68]. While such panels offer benefits, such as reduced material costs and improved flexibility, manufacturing difficulties and costs can be decreased. For example, the sandwich panels of a foam core could provide core homogeneity and thermal insulation properties. That makes them an attractive alternative to the typical panel with relatively high thicknesses. Notably, honeycomb panels have become more cost-effective and demonstrate improved structural integrity, stiffness, and load-bearing capacity for thicknesses greater than 24 mm due to the increased empty spaces within the core that reduce relative material costs [8].

Wood-based sandwich panels are material-efficient and sustainable thanks to advancements in manufacturing. Such techniques as eco-friendly adhesives, automated lines, and 3D printing improve production and expand their uses in construction despite slightly high costs and complexity challenges.

3.2. Innovations in Material Technology

In addition to fire resistance and improved acoustic properties, notable innovations in sandwich panels affecting the construction industry include the application of GFRP in the manufacturing of the sandwich panels, enhancing their resistance to bending and compression stresses, and elevating their structural integrity and long-term uses [10,69]. For example, GFRP-faced and wood-based core honeycomb sandwich panels, utilized in sustainable prefab building construction, showed variable flexural strengths depending on the core composition: MDF honeycomb panels achieved a maximum bending stress of 13.30 MPa, those filled with wheat straw reached 41.95 MPa, and panels with a plywood core exhibited up to 107.14 MPa [70]. In another study, the GFRP sandwich panels, with homogeneous-core configurations composed of high- and low-density balsa layers separated by a circular adhesive interface or GFRP arch, demonstrated flexural strengths of approximately 29.90 MPa to 34.14 MPa [71]. Another study found that locally stiffening GFRP composite sandwich panels with balsa wood cores significantly increased their punching resistance. This enhancement enabled the panels to support a concentrated load capacity that is three times greater than that of the non-stiffened panels [72]. A useful approach was found in a study of non-wood-based GFRP composite sandwich panels with different core materials (PUR vs. polyethylene terephthalate (PET) foams), which showed that the inclusion of longitudinal GFRP web reinforcement enhanced the load-bearing capacity of the web–core sandwich panels significantly, achieving an increase of 4.3 to 9.3 times compared to the homogeneous-core specimens. This improvement is attributed to the GFRP webs’ ability to substantially boost the shear strength of the panels, thereby making a significant contribution to their overall load-bearing capacity [10]. This strategy could be incorporated into wood-based sandwich panels. This type of reinforcement is particularly valuable in environments requiring strong, durable materials to withstand extreme conditions. Further advancements have been made with panels featuring surfaces of plywood combined with thermoplastic glass fibre/polypropylene (PPE) composites, which have shown improved environmental resistance and fire safety [10]. Additionally, the tensile strength of GFRP sandwich panels was increased significantly to about 512.50 MPa and exhibited brittle behaviour [10].

Innovations in core materials have also played a key role in improving the functional properties of sandwich panels. New introductions include low-density fiberboard cores and cores made from natural fibres like coconut fibres and cork agglomerates. These materials provide superior thermal insulation and contribute to sound absorption, making them ideal for residential and educational environments where noise reduction is a priority [73]. Structural innovations such as rib-stiffened cores, as mentioned above, and honeycomb configurations have also been developed to reduce weight without compromising stiffness or load capacity. These designs are particularly suited for prefabricated housing, where speed and efficiency of construction are required [74].

The integration of sustainable materials is at the forefront of recent innovations. Panels constructed from renewable resources like jute, burlap, and aerated concrete cores highlight the industry’s shift towards more sustainable building practices. These materials reduce the ecological footprint of construction projects and enhance the panels’ structural and thermal properties [75].

4. Properties of Wood-Based Sandwich Panels for Buildings

4.1. Mechanical Properties and Their Applications in Construction

Wood-based sandwich panels have high strength-to-weight ratios that exceed those of common construction materials such as solid wood, concrete, and steel [4,76,77]. This makes these panels perfect for situations that require lightweight and strong materials. For example, their use in prefabricated construction demonstrates their ability to reduce overall wood consumption and construction weight while maintaining structural integrity [70]. It is essential to consider the ratio of strength to density when evaluating wood-based and other sandwich panels. This ratio reflects the panel’s structural efficiency, combining its mechanical strength and weight. For instance, in the case of sandwich-structured composite plywood panels, the variations in the veneer thickness ratio in plywood significantly change the stress distribution in each layer of the sandwich panel. Also, it influences the stiffness of a sandwich panel. Stiffness can be increased by increasing the thickness ratio of the parallel-oriented veneer sheets [78]. Moreover, the low density suggests a hollow structure, which contributes to the reduced weight and provides excellent thermal and sound insulation properties. This property is important in various applications, especially in the construction and aerospace industries, where lightweight yet strong materials are highly desirable. Therefore, a comprehensive understanding and optimization of this strength-to-density ratio is critical for maximizing the structural performance of sandwich panels and ensuring their cost-effectiveness across various applications. Further research into core designs has shown that innovative approaches can significantly enhance the mechanical performance of wood-based sandwich panels. For example, the research of the wooden sandwich panels with an auxetic core and oval cells discovered a modulus of elasticity (MOE) of 3.30 GPa and a bending strength of 26.60 MPa while maintaining a density below 400 kg/m³ and a thickness of 20 mm, making them effective substitutes for traditional wood-based panels due to their advantageous strength-to-weight ratio [79]. In a different study, novel wood-based sandwich composite panels, featuring an interlocking plywood kagome lattice core and grooved particleboard facings, demonstrated a flatwise compressive strength of 2.64 MPa and an edgewise compressive strength of 6.40 MPa, while maintaining a relatively low density of 392 kg/m³ and a total panel thickness of 38 mm, offering competitive strength properties suitable for versatile structural applications [20]. Similarly, bamboo–wood corrugated sandwich panels demonstrated that panels with a thickness of 18 mm exhibited a modulus of rupture (MOR) of 38.53 MPa, an MOE of 5.21 GPa, and a compressive strength (CS) of 3.60 MPa, providing an option for non-structural applications [80]. Additionally, research on wood-based sandwich panels with corrugated cores demonstrated that these panels, manufactured with a panel thickness of 47.80 mm, exhibited an MOE of 1.45 GPa and an MOR of 4.64 MPa, showing excellent construction properties while maintaining a low density of 228 kg/m³ [81]. As mentioned above, innovative materials, such as GFRP, can strengthen wood-based sandwich panels and improve their mechanical performance under bending and compression stresses [69,70,76]. While traditional technologies were focused on bonding between the core and faces of the panels, some studies showed that panels with incompletely glued surfaces had discovered that even with partial bonding, the mechanical properties could be better than expected, as non-glued areas of the core contribute to the overall strength [82].

To illustrate the practical applications of these advancements, wood-based sandwich panels with plywood face layers were designed for lightweight, fast-transformable housing applications. Panels with a stiffener/foam core, specifically thermoplastic glass fibre (TPGF)/PP, and bonded to plywood achieve an average MOE of 6.20 GPa and a flexural strength of 26.10 MPa with a density of 325 kg/m³ and a thickness of 64 mm. Alternatively, panels featuring a thermoplastic composite core attained an MOE of 4.18 GPa and a flexural strength of 22.60 MPa, with a reduced density of 235 kg/m³ and a thickness of 59 mm. Compared to conventional 50 mm thick plywood, which has an MOE of 9.20 GPa and a flexural strength of 36.60 MPa at a density of 680 kg/m³, these sandwich panels could offer a significant reduction in weight comparing the MOE and density [42]. Another study on wood-based sandwich panels examined panels made from particleboard, MDF, OSB, and plywood, which demonstrated, when used as internal layers and glued with PUR adhesive, significantly increased mechanical properties: an MOE of 8.88 GPa and an MOR of 92.90 MPa, while maintaining a thickness of 12.3 mm for MDF and 3.64 mm for plywood [83].

The flexural properties and densities of various sandwich panels are presented in

Table 1. Mechanical properties of various wood-based sandwich panels.

Panel Type	Core Material	MOE (GPa)	MOR (MPa)	Density (kg/m³)	Thickness (mm)	Source
Wood-based panels with plywood faces	Stiffener/foam	6.20	26.10	325	64	[42]
Wood-based panels with plywood faces	Thermoplastic composite	4.18	22.60	235	59	[42]
Conventional plywood	None	9.20	36.60	680	50	[42]
Wood-based panels (particleboard, MDF, OSB, plywood)	Various internal layers	8.88	92.90	N/A	MDF: 12.30, Plywood: 3.64	[83]
Wooden panels with auxetic core and oval cells	Auxetic core, oval cells	3.30	26.60	<400	20	[79]
Wood-based composite panels	Kagome lattice core, particleboard facings	N/A	Flatwise: 2.64; edgewise: 6.4	392	38	[20]
Bamboo–wood corrugated sandwich panels	Corrugated core	5.21	38.53	N/A	18	[80]
Wooden panels with corrugated cores	Corrugated core	1.45	4.64	228	47.8	[61]

.

Exploring the mechanical properties of wood-based sandwich panels reveals their potential in modern construction methodologies. It highlights their superior strength-to-weight ratios and adaptability in various applications, from residential to aerospace industries. By optimizing the interplay between the core material and faces, these panels can offer enhanced performance under mechanical stresses while contributing to sustainability in the construction sector.

4.2. Thermal Insulation Capabilities Linked to Sustainable Construction

Effective thermal insulation is a unique feature of wood-based sandwich panels, making them suitable for sustainable construction projects. The core materials in wood-based sandwich panels, such as foam or balsa, are chosen for such properties as low λ, which can notably improve the building’s thermal insulation. Because of this quality, less energy is used for heating and cooling, which lowers operational costs and carbon emissions. Such panels are ideal for energy-efficient structures; for example, the λ of thick plywood-faced sandwich panels with a fiberboard core of a density of 340 kg/m³ or 410 kg/m³ was 0.070 or 0.077 W/mK [13], causing a 10% difference. Another study showed that eco-sustainable wood waste panels made from pine, oak, and mahogany provided λ values ranging from 0.071 to 0.084 W/mK [45]. The λ values of insulated sandwich panels from natural rubber and rubber wood were 0.070–0.080 W/mK [52].

Comparatively, foam-filled sandwich panels, often utilizing materials like PUR and EPS (expanded polystyrene), generally produced λ values ranging from 0.022 to 0.040 W/mK, which were lower than those of solid wood, which varied from 0.100 to 0.210 W/mK [13,84]. For instance, PUR foam-filled panels typically had a λ value of around 0.022 W/mK, providing excellent insulation properties [85]. This makes foam-filled panels highly efficient in minimizing heat transfer, thus further reducing energy consumption in buildings.

Additionally, the λ values of the sandwich panels, which are manufactured with different types of faces, such as alder (Alnus), birch (Betula) and Scots pine (Pinus sylvestris) veneer, and aluminium and polypropylene as core materials in sandwich panels, were investigated. The highest values were obtained from alder for the aluminium core panels at 0.108–0.262 W/mK and Scots pine at 0.111–0.259 W/mK for the polypropylene core panels as wood species [86]. Moreover, ferrocement sandwich panels filled with coconut fibres have a λ value as low as 0.221 W/mK [87]. That was comparable to the λ values of coconut wood CLT, which ranged from 0.153 to 0.264 W/mK [88]. The λ value of CLT panels measured was 0.12 W/mK [89]. In addition, the properties of sandwich panels made of cork agglomerate and wood veneer were investigated to highlight the possibility of utilizing renewable resources to improve thermal performance in building designs [73]. Further research analyzed sandwich panels made of cross-insulated timber (CIT). CIT was combined with a rigid PUR foam core. A comprehensive life cycle analysis (LCA) evaluated the environmental impacts of CIT sandwich panels and highlighted their excellent thermal insulation capabilities with minimal material consumption [30]. Additional research has demonstrated that these panels might effectively replace the traditional insulators in building envelopes. That could aid in creating more ecologically and energy-efficient building solutions [31]. It is evident that a variety of sandwich panels, with thermal conductivities ranging from as low as 0.070 W/mK to as high as 0.262 W/mK, are suitable for energy-efficient building applications due to their effective insulation properties. These panels include plywood, wood waste, natural rubber wood, wood veneers with metal cores, and novel materials like cork agglomerate; compared to traditional materials, like steel and concrete, steel structures have a λ value of approximately 50 W/mK and concrete around 1.60 W/mK, whereas wood-based sandwich panels can achieve much lower values, reducing energy consumption in buildings; see

Table 2. Thermal conductivity (λ) of wood-based sandwich panels compared to other building materials.

Material Type	Specific Material	Density (kg/m3)	Thermal Conductivity—λ (W/mK)	References
Wood-based sandwich panels	Plywood-faced sandwich panel of the fiberboard core of a density of 340 kg/m3	340	0.070	[13]
	Plywood-faced sandwich panel of the fiberboard core of a density of 410 kg/m3	410	0.077	[13]
	Eco-sustainable wood waste panel	282 to 398	0.071 to 0.084	[45]
	Natural rubber and rubber wood panel	410 to 550	0.070 to 0.080	[52]
	Alder veneer with aluminium core	N/a	0.108 to 0.262	[86]
	Scots pine veneer with polypropylene core	N/a	0.111 to 0.259	[86]
	Ferrocement with coconut fibre	N/a	0.221	[87]
Wood-based materials	Soft wood	348–661	0.680–1.12	[90,91]
	Hard wood	615–750	1.060 to 1.250	[90,91]
	Cross-laminated timber (CLT)	480–500	0.120 to 0.130	[92,93]
	Coconut wood CLT	655 to 972	0.153 to 0.264	[88]
	Oriented strand board (OSB)		0.13	[94]
	Laminated strand lumber (LSL)		0.081 to 0.126	[95]
	Plywood (lightweight)	560	0.150	[90]
	Plywood (heavyweight)	700	0.150	[90]
Additional materials	Concrete	1618	0.8 to 2.0	[90,96]
	Steel	7850	50	[52]
	Glass	2500 to 2600	0.8	[97]
	Aluminum	2700	237	[98]

. The above findings underscore the superior thermal insulation properties of wood-based sandwich panels, making them a good choice for sustainable and energy-efficient construction.

4.3. Sound Insulation and Absorption in Building Design

In addition to their thermal properties, wood-based sandwich panels are highly valued for their sound insulation and absorption capabilities, making them an excellent choice for noise reduction in various building environments. These panels are especially valued for reducing noise in schools and residential buildings. Studies demonstrated that the use of wood veneer panels with cork cores could reduce noise transmission [73,99] since cork agglomerates naturally absorb sound. Having two distinct functions highlights the adaptability and significance of the panels in modern architectural design when soundproofing is becoming an increasingly important factor. In addition, an extensive study of prefabricated façade panels, including massive, sandwich, and frame designs, indicated that wooden sandwich panels had an average sound transmission class (STC) value of 22 dB and provided sound insulation of 37–47 dB [31]. The results from this study revealed that these panels could minimize noise in construction applications. It makes them an excellent option for offices and libraries needing quiet areas. Another study examined insulated sandwich panels from natural rubber and rubber wood that exhibited a sound transmission loss of 35–80 dB, approximately twice better than current wall materials [52]. Further research on the structural insulated panels (SIPs) consisting of OSB faces and expanded EPS core displayed that the airborne sound reduction index (Rw) value of these panels could be reduced to 39 dB [100]. Compared to these data, in terms of STC, a three-layer bare CLT wall (95 mm to 115 mm) typically had a sound insulation level of 32–34 dB [101].

Table 3. Sound transmission class (STC) rating chart [102].

STC	What Can Be Heard at This Level
25	Soft speech can be heard and understood.
30	Normal speech can be heard and understood.
35	Loud speech can be heard and understood.
40	Loud speech can be heard, but not understood.
45	The threshold at which privacy begins.
50	Loud sounds can be heard, but are very faint.
60+	At this level, good soundproofing begins. Neighbours generally are not disturbed by very loud speech from inside.

lists the STC rating values.

Table 4. Physical–mechanical properties of wood-based panels [103] (adapted with permission from Smardzewski et al. 2015).

Code	Type of Material	Thickness (mm)	Density (kg/m³)	Porosity	MOR (MPa)	MOE (GPa)	Sound Absorption Coefficient (α)
	High-density fiberboard (HDF) + rattan mat HDF 8 mm, rattan mat 3 mm	11.0	753	0.50	28.1 L * 25.6 P **	1.99 L 1.89 P	0.01–0.4
	High-density fiberboard (HDF) + bamboo mat HDF 8 mm, bamboo mat 2 mm	10.0	848	0.43	37.0 L 29.2 P	5.22 L 2.64 P	0.01–0.16
	Honeycomb + Lloyd loom mat Honeycomb paper core 5 mm, 2 × facing HDF 2 mm, 1 × facing loom mat 1.2 mm	10.2	413	0.72	16.6 L 11.4 P	2.20 L 1.93 P	0.01–0.23
	Honeycomb + synthetic leather Honeycomb paper core 5 mm, 2 × facing HDF 2.5 m, 1 × facing synthetic leather 0.6 mm	10.6	517	0.66	19.7 L 13.6 P	2.42 L 1.98 P	0.01–0.08
	Honeycomb + veneer Honeycomb paper core 5 mm, 1 × facing HDF 2.5 mm, 1 × facing oak veneer 2.3 mm	9.8	456	0.70	15.8 L 18.1 P	2.87 L 2.12 P	0.01–0.18
	Honeycomb + oak + texture Honeycomb paper core 5 mm, 2 × facing oak veneer 2.75 mm	10.5	471	0.69	14.4 L 11.8 P	2.99 L 1.39 P	0.01–0.27
	Honeycomb Honeycomb paper core 5 mm, 2 × facing HDF 2.5 mm	10.0	382	0.75	6.6 L 6.3 P	2.56 L 2.43 P	0.01–0.25
	Poplar plywood	18.4	515	0.66	40.5 L 40.9 P	4.88 L 4.73 P	0.01–0.12
	Exotic plywood	7.9	354	0.76	32.9 L 0 P	3.39 L 0 P	0.04–0.125
	Particleboard	16.0	481	0.68	9.5 L 0 P	2.08 L 0 P	0.04–0.13
	Medium-density fibreboard (MDF)	18.0	558	0.63	31.4 L 0 P	3.17 L 0 P	0.02–0.13
	Purenit (recycling material)	3.1	553	0.63	6.3 L 0 P	0.500 L 0 P	0.01–0.27
	Oriented strand board (OSB/3)	17.5	613	0.59	30.5 L 18.8 P	6.13 L 3.41 P	0.01–0.14
	DendroLight—core Pine wood core 22 mm	22.3	270	0.82	1.8 L 1.2 P	0.2 L 0.15 P	0.01–0.64
	DendroLight—HDF Pine wood core 14.5 mm, 2 × facing HDF 4 mm	22.5	493	0.67	22.3 L 22.5 P	2.92 L 2.85 P	0.01–0.12
	DendroLight—birch plywood Pine wood core 14.5 mm, 2 × facing birch plywood 4 mm	22.5	459	0.69	55.5 L 23.8 P	9.17 L 4.39 P	0.01–0.13
	Tube particleboard	28	220	0.85	1.1 L 0.6 P	0.52 L 0.11 P	0.5–0.65

* L—along the fibres of faces; ** P—perpendicular to the fibres of faces.

presents an examination of the physical and mechanical properties of various wood-based sandwich panels [103]. The analysis indicates that panels of high-density fiberboard HDF composites, like HDF with rattan and bamboo mats, have a high density (753–848 kg/m³), sound absorption coefficient from 0.01 to 04, and strong mechanical properties, with an MOR up to 37 MPa and an MOE up to 5.22 GPa, making them ideal for robust structural applications. Honeycomb composites, featuring a paper core, have moderate densities (382–517 kg/m³), sound absorption coefficient from 0.01 to 0.27, and MOR values up to 19.7 MPa and MOE values up to 2.99 GPa, balancing strength and weight. DendroLight sandwich panels, with a pine and birch wood core, are moderate-density (459–493 kg/m³), offering sound absorption from 0.01 to 0.13 and high mechanical strength, with an MOR up to 55.5 MPa and an MOE up to 9.17 GPa for birch plywood facings. These materials are ideal for applications requiring high mechanical strength, light weight, and sound insulation [103].

The wide range of applications for sandwich panels highlights their adaptability and significance in contemporary architectural design, where efficient soundproofing is becoming a more critical consideration.

4.4. Fire Resistance in Wood-Based Sandwich Panels

Fire resistance is an important feature of construction materials or products, such as wood-based sandwich panels. They are characterized by fire resistance, which can be upgraded with fire retardants or by using non-flammable core materials such as gypsum wall boards, allowing them to meet or go above the high fire resistance criteria imposed for construction materials [31]. Wood has some fire resistance due to its charring capabilities, but these panels can be improved to meet or exceed these requirements.

Sandwich panels, when paired with non-combustible boards of the A1 or A2 class [104], have been shown to ensure the safety of residential structures effectively, as shown in

Table 5. Fire safety ratings of construction materials (EN 13501-1) [104,106].

Class	Description	Contribution to Fire
A1	Non-combustible	No contribution to fire
A2	Non-combustible with limited contribution	Very limited contribution to fire
B	Combustible with very limited contribution	Limited contribution to fire
C	Combustible	Moderate contribution to fire
D	Combustible	High contribution to fire
E	Combustible	Very high contribution to fire
F	Unclassified	No performance determined

[105,106]. As a result of this structure, their suitability for safety-critical applications was improved, showing the potential of these panels to increase protection against fire. Under Czech law, wood-based sandwich structures with flammable structural elements are restricted to a maximum fire height of 9 m. However, they can still meet the 90-min fire resistance requirement for structural element [105].

Specific test procedures are employed to accurately evaluate the fire resistance of wood-based sandwich panels. One commonly used method is the ISO 834 Standard “Fire-resistance tests—Elements of building construction—Part 1: General requirements” [107], which exposes panels to a standardized temperature curve in a controlled furnace environment. The temperature within the furnace is increased according to the ISO 834 time–temperature curve, and the panels are monitored for temperature rise on the unexposed surface and structural integrity [107]. Another standard method is ASTM E119, “Standard Test Methods for Fire Tests of Building Construction and Materials”, which determines the fire resistance of building materials and structural elements [108]. This involves subjecting a sandwich panel to fire exposure in a furnace, measuring the time it takes for the panel to reach certain temperature thresholds on the unexposed surface, and evaluating its ability to maintain structural stability during and after fire exposure.

For instance, a study measuring the fire resistance of a 2.59 m × 2.59 m (8.5 ft × 8.5 ft) sandwich panel composed of 0.64 cm (0.25 in) thick E-glass/Derakane 510A faces, a 7.62 cm (3 in) thick balsa wood core, and a 3.18 cm (1.25 in) protective layer of Structo-Guard was conducted; it was found that the panel had a mid-span deflection significantly below the 60.96 cm (2 ft) limit after one hour of exposure to a maximum flame temperature of 2000 °F (1093.3 °C) [109]. Prefabricated wood-based sandwich panels from another research work with a thickness of 76 mm (3 in), using thermal insulation materials such as PUR, EPS, XPS (extruded polystyrene), GPS (graphite polystyrene), honeycomb, rock wool, or glass wool in the middle layer, were found to have an average fire resistance of 30 to 90 min [31]. Also, wood-based sandwich panels with a thickness of 59 mm, composed of plywood faces and a corrugated thermoplastic composite core (glass fibre/polypropylene), demonstrated fire resistance of 30 to 90 min, with specific flexural stiffness being 60% higher than that of a conventional plywood panel [11]. Different studies examined the fire resistance of wood-based sandwich panels with OSB faces and insulation cores of either mineral wool or EPS. It was found that mineral wool core panels exhibited superior fire resistance, maintaining structural integrity and lower surface temperatures during fire exposure, compared to EPS core panels, with mineral wool panels achieving a surface temperature of 37 °C after 120 min, significantly better than the surface temperature of 220 °C observed for EPS core panels [105].

Compared to this, another research work examined the fire resistance of large CLT panels. The structure remained intact during the whole 60 min test [78]. Further investigations have explored panels’ structural performance and fire resistance with various face materials and cores. For instance, some studies focused on panels with plywood faces and thermoplastic glass fibre/polypropylene composites [42]. These results highlighted the need for continued innovation to fully explore the potential of these materials in fire-prone areas. The studies emphasized the importance of material composition in enhancing fire safety, particularly noting that the chemical composition of the polyols used in the foam core significantly improved fire resistance.

In addition to these material innovations, fire protection systems play a crucial role in enhancing the fire resistance of wood-based sandwich panels. Research showed that wood-based sandwich panels protected with calcium silicate boards exhibited significantly lower temperature evolution within the panel, reducing the influence of the core material. For example, studies have reported that composite sandwich panels with 25 mm thick calcium silicate boards adhered to the bottom face could maintain temperatures at the top face well below critical levels, with the temperature at the top face remaining at 52 °C and 39 °C even after 80 min of fire exposure, effectively delaying heat transfer to the core and enhancing fire resistance [110]. This protection is critical to ensure that the core material does not significantly contribute to spreading fire. In contrast, wood-based sandwich panels without protective layers are heavily relied on the fire resistance of the type of core materials. Materials such as mineral wool and phenolic foam cores have been studied for their fire-resistant properties. Mineral wool cores provide high fire resistance, class up to EL120, and continue to perform their function in the event of a fire for up to 120 min (2 h) due to their non-combustible nature and ability to withstand high temperatures [111,112]. Phenolic foam cores, while combustible, form a char layer when exposed to fire, which acts as a barrier to slow down heat penetration [113]. The EL classification system indicates the duration (in minutes) over which a material can withstand fire exposure while maintaining its structural integrity and limiting temperature rise.

Another approach involves applying intumescent coatings to the surface of a wood-based sandwich panel. These coatings expand when exposed to high temperatures, forming an insulating char layer that protects the underlying materials. Studies have shown that intumescent coatings can significantly enhance the fire resistance of wood-based sandwich panels, providing additional time for evacuation and fire control measures [114]. Thus, lightweight, fire-resistant wood-based sandwich panels were developed using a vermiculite core and plywood faces. They achieved a maximum temperature of only 83.2 °C during a 120 min Bunsen burner test, indicating superior fire resistivity and thermal insulation performance [115].

These studies demonstrate how fire safety technology has advanced in the building sector. They show how, with the proper planning and preparation, wood-based sandwich panels may provide several benefits over more conventional building materials. Because of their lightweight design, they may save costs from foundation and structure, labour, and construction time due to their reduced structural load and ease of installation. However, despite these advantages, it is crucial to recognize the initial capital investment and market acceptance challenges that currently prevent their uses in the building sector [116].

5. Applications of Wood-Based Sandwich Panels in Construction

5.1. Conventional and Modern Uses in Construction

The previous sections discussed the mechanical, thermal, and acoustic properties and fire resistance of wood-based sandwich panels with kind of brief introduction to the applications of these panels. Next, the discussion will turn to real-life applications of wood-based sandwich panels. Figure 4 summarizes the applications of wood-based sandwich panels in construction.

One of the most popular materials used in residential and light commercial construction is SIPs. They have two structural face layers and an insulating foam core placed between them. Typically, faces are made of OSB. SIPs are made under regulated conditions and may be customized to almost any building design, making for a strong, cost-effective, and energy-efficient structure. Installed SIPs save energy costs by maintaining sustainable building principles, which are roughly 50% more energy-efficient than conventional timber framing; see Figure 5 [117]. Products like Kingspan TEK Cladding Panels are SIPs that provide superior thermal performance and are used in residential and commercial buildings [118].

A case study conducted in the United States compared the use of SIPs with traditional wood framing in residential construction. The SIP home required 120 labour hours and was completed in 18 h, while the conventional wood-framed home required 140 labour hours and took 34 h to complete. SIPs saved about two-thirds of the site framing labour for walls and roofs and reduced construction cycle time by a similar magnitude. However, SIP construction could generate 12% factory waste in panel areas, compared to minimal waste observed on-site for the wood-framed home [119]. Another evaluation in the United States assessed the use of wood-based SIPs in manufactured housing, comparing it with traditional construction methods. Champion Enterprises built the first HUD-code (U.S. Department of Housing and Urban Development)-approved manufactured homes using SIPs. The SIP home, constructed at Champion’s Redman factory in Silverton, Oregon, demonstrated nearly 50% energy savings compared to homes built to minimum HUD standards, consuming 11,249 kWh over a seven-month period. The SIP construction used 60 panels compared to more than 1000 parts typical of traditional framing, reducing complexity and labour. The construction process showed that the SIP home could be built in 12 days, with the first half taking about 6 h longer than a typical house but the second half being completed much quicker as workers became more familiar with the process and experienced fewer interruptions [120].

Beyond SIPs, another practical application of wood-based sandwich panels is the ZIP System^®. In real-life applications, ZIP System^® wood-based sandwich panels are commonly applied in constructing walls and roofs for their integrated approach to sheathing and insulation. They provide a simplified installation procedure, increased energy efficiency because of the integrated insulation, and an integrated moisture barrier that enhances the building’s thermal envelope. These panels provide rapid building time frames while complying with energy codes, offering a strong foundation for residential and commercial buildings; see Figure 6 [121].

Starcell SPA offers another type of wood-based sandwich panels for construction. They show multiple characteristics, such as increased durability, a lightweight design, and various application alternatives. It is possible to use these panels in various architectural applications, such as ventilated façades, raised floors, and false ceilings, because they have been specifically designed for that purpose. They offer more environmentally friendly and sustainable alternatives to conventional materials. Also, they emphasize enhanced technical performances and environmental benefits [122].

Furthermore, a hybrid sandwich wall element created by Metsä Wood and its partners is set to modernize offsite construction. This innovative method combines concrete and Kerto^® LVL (laminated veneer lumber) [123]. The load-bearing core of a hybrid sandwich wall element consisted of a Kerto LVL panel. An insulating layer and a reinforced concrete façade came next. By combining the strength of concrete with the carbon-sequestering properties of wood, their dual composition decreases emissions and reduces the need for concrete. These panels, which came from certified sustainable forests, would enhance environmental advantages by providing improved thermal insulation and enhancing building energy efficiency. Towards their life cycle end, the wood elements would be recycled or converted into bioenergy. These panels are proposed as especially well suited for uses requiring environmental sustainability and structural integrity, like energy-efficient housing developments and eco-friendly building façades.

These diverse applications highlight the versatility and advantages of wood-based sandwich panels in modern construction.

5.2. Sustainability and Environmental Impacts

Sandwich panels made of wood are an excellent example of sustainable construction technology. They combine the environmental benefits of wood with state-of-the-art engineering approaches to meet today’s sustainability and energy efficiency demands. Using wood’s natural capacity of absorbing carbon dioxide throughout the production of wood, i.e., the growth of trees, and storing carbon over the life span of the wood products, these wood-based sandwich panels can balance the carbon dioxide emissions that result from the production, transportation, and installation processes [45,57,124,125,126].

Wood is a sustainable and renewable material that can be managed responsibly and is a natural carbon sink. All these highlight its ecological value [45,57,124,127]. LCA analysis shows that wood-based sandwich panels have an exceptionally low global warming potential (GWP), with a carbon footprint as low as 3.5–5.4 kg CO₂ equivalent (eq) per m², when compared to conventional building materials like concrete and steel; see Figure 7 [45,124].

Another case study conducted in Canada in 2019 compared wood aluminium-laminated (WAL) panels with aluminium honeycomb panels (AHPs) using the LCA [129]. The study analyzed the environmental impacts of manufacturing the WAL panels with three different cores—MDF, OSB, and plywood—and compared them to AHP. The results showed that WAL panels had significantly lower environmental impacts on human health, climate change, and resource depletion. For example, the climate change impact for WAL panels ranged from 27.90 to 31.20 kg CO₂ eq, compared to 41.50 kg CO₂ eq for AHP. Additionally, WAL panels required 4.24 to 4.81 MJ/m² of primary energy, whereas AHP required 6.29 MJ/m².

Sustainability certifications, such as the Forest Stewardship Council (FSC) [130] and the Programme for the Endorsement of Forest Certification (PEFC) [131], are required to ensure that the wood used in these panels comes from properly managed forests. These certificates promote biodiversity and sustainable land use and significantly improve the environmental standing of wood-based sandwich panels [57,127]. The Sustainable Forestry Initiative (SFI) [132] is another program that sets standards for forest management focusing on North America. SFI certification ensures that forests are managed in a way that preserves natural habitats, protects water quality, and supports biodiversity, similar to the globally recognized PEFC. FSC is widely implemented in North America and globally.

Incorporating LEED (Leadership in Energy and Environmental Design) [133] certification can also add value, as it recognizes best-in-class building strategies that meet key sustainability metrics, including energy savings, water efficiency, CO₂ emission reductions, and management of resources. Moreover, Environmental Product Declarations (EPDs) [134] provide quantified environmental data to compare products that fulfil the same function, thus helping users make informed decisions about the materials they use and their overall environmental impact.

Wood-based sandwich panels’ recyclability and efficient end-of-life management highlight their environmental friendliness. These panels are highly recyclable, as wood components can be used in other construction projects or transformed into new wood-based products [45]. Furthermore, these panels can serve as a bioenergy source at the end of their life cycle through incineration or other thermal processes [127]. Additionally, the thermal insulation capabilities of wood-based sandwich panels result in lower energy consumption and emissions during the use phase of construction, highlighting their importance in improving energy efficiency [127,135]. This feature is especially useful in increasing the environmental benefits of structures built with these panels.

The long-term performance and durability of wood-based sandwich panels are critical factors in their adoption for widespread construction use. These panels must withstand various environmental conditions, including moisture, temperature fluctuations, and UV exposure. Studies showed that wood-based sandwich panels, when properly treated and coated, exhibited good resistance to moisture absorption, maintaining structural integrity and preventing rot and decay [136,137,138]. Direct liquid water exposure, while not intended for these panels, could potentially damage the wood-based faces if it occurs accidentally [139]. Using moisture-resistant adhesives and coatings on the core could enhance durability, and low-density wood cores could provide good thermal insulation that is stable over the long term [140]. Moreover, innovations, such as the integration of UV-resistant polymers and moisture barriers, could further enhance the panels’ durability. For instance, silicone-based and ZnO-based coatings could provide wood with durable UV protection [141,142]. However, there is a need for research to further develop even robust solutions to address potential issues such as delamination and thermal expansion, ensuring the panels’ longevity and reliability in diverse climates.

In summary, wood-based sandwich panels are recognized as a highly sustainable construction material, offering considerable environmental advantages throughout their life cycle—from raw material sourcing to end-of-life disposal or recycling. Through the integration of natural and recyclable materials, such as those highlighted in studies focusing on flax FRP faces with cardboard cores [143], lightweight wood-strand panels [144], and GFRP/wood-based honeycomb structures filled with wheat straw [70], these panels exemplify the shift towards eco-friendly building solutions. The emphasis on sustainability certifications, recyclability, and superior thermal performance further asserts the role of wood-based sandwich panels in paving the way for sustainable construction practices, aligning modern construction demands with the imperative for environmental stewardship.

5.3. Challenges and Opportunities

In addition to the applications and advantages discussed above, it is important to address the challenges and opportunities associated with wood-based sandwich panels. The benefits and uses of wood-based sandwich panels are well documented. A detailed examination found mixed agreement and disagreement in this sector. Many studies highlight the panels’ superior thermal insulation and suitable mechanical properties, but assessments of their long-term durability and environmental stress tolerance vary significantly. The inconsistency of these results calls for further investigations and testing uniformity. The literature thoroughly examines the environmental advantages of the panels, such as carbon footprint and energy efficiency. LCA analysis must consider all environmental aspects, from raw materials extraction to product utilization or recycling [145]. The investigations confirmed the panels’ environmental sustainability and guided their design and manufacture. These assessments should cover all stages, beginning with the extraction of the materials and ending with their disposal or recycling. Such a study might show ways to decrease the carbon impact of the panels further, enhancing their environmental credentials.

The mechanical properties and structural performance of wood-based sandwich panels also present both challenges and opportunities. Improving the mechanical properties, such as bending and compression strengths, is crucial for the broader adoption of these panels in various construction applications. The incorporation of materials like GFRP and the optimization of geometric configurations, such as rib-stiffened cores, have shown significant improvements in mechanical performance. However, further research is needed to develop materials and configurations that can provide consistent and enhanced performance under diverse conditions.

It is essential to increase the fire resistance of wood-based sandwich panels without adding any dangerous or ecologically damaging chemicals, including making panels that do not burn would be a significant advancement, investigating environmentally friendly production techniques where lower energy consumption and waste is necessary to improve sandwich panel sustainability [48], and developing more efficient methods for recycling or reusing industrial waste, employing sustainable energy sources in production, and improving adhesive curing processes are all possible areas of proceeding [13]. Protective layers such as reinforcing wood-based sandwich panels with gypsum boards or other fire-resistant materials can significantly improve their fire resistance [31]. Fire safety, building codes, and sustainability certifications for wood-based sandwich panels in construction should also be examined. Understanding these criteria may assist manufacturers and construction specialists in improving sandwich panels for environmentally friendly construction, which is crucial for industry acceptability.

Research is also needed to determine the long-term performance of wood-based sandwich panels under various environmental conditions, including temperature, humidity, and biological factors [138,146]. Factors like fluctuating temperatures, varying humidity levels, and prolonged exposure to UV radiation can significantly impact the performance of these panels over time. Additionally, using idealized laboratory conditions in many studies may not accurately represent real-world scenarios. Addressing this gap through field testing and long-term performance monitoring in actual environmental conditions will provide more reliable data on durability, thermal performance, mechanical integrity, and overall resilience. This approach will help ensure that the panels can withstand the diverse and unpredictable conditions they will face in real-world applications.

Furthermore, improving insulating core materials or making them lighter, more sustainable, or more effective would increase panel usefulness. The building industry is moving toward sustainability, and wood-based sandwich panels have significant potential for growth. Although these materials have been better understood and used, numerous untapped research areas still exist that could address knowledge gaps and inspire new uses. Research into smart building technology and wood-based sandwich panels is promising. It integrates advanced automation and data analytics to enhance building efficiency, user experience, and operational management [147]. Built-in sensors for structural health monitoring and adaptive insulating properties that respond to environmental changes may create smart building systems that improve energy efficiency and comfort for residents [148,149,150]. Investigating customization possibilities in designing and producing wood-based sandwich panels could introduce new opportunities for architectural uses [151]. Research panels that can be customized in shape, size, or aesthetic finish to meet unique design requirements would improve their attractiveness and adaptability in construction projects. Moreover, exploring the role of wood-based sandwich panels in modular and prefabricated construction represents another critical area for future research [31,69,74,126]. These panels’ light weight and strength may make them perfect for more efficient, waste-free construction processes. How these panels may be optimized for modular building, including transportability, assembly efficiency, and personalization could expand sustainable construction methods.

These study themes might develop wood-based sandwich panels and promote green building. Academic institutions, industrial businesses, and regulatory authorities should work together to investigate and ensure that wood-based sandwich panels continue to affect sustainable building.

6. Concluding Remarks

This review highlights the advancements and applications of wood-based sandwich panels in modern construction. These panels offer numerous benefits, including superior thermal insulation, high strength-to-weight ratio, and the use of renewable materials, making them ideal for green construction, from residential to commercial buildings. However, due to the nature of wood as a biomaterial, several challenges and shortcomings need to be addressed. Long-term exposure to environmental factors, such as moisture and temperature fluctuations, can negatively impact the structural integrity and mechanical properties of wood-based sandwich panels, even though their thermal insulation properties remain effective. Fire resistance is also critical, although current protection systems, such as calcium silicate boards, have shown promise.

Key findings and implications are given as follows:

• Structural performance. These panels’ high strength-to-weight ratio enhances structural performance while minimizing the load on foundations and supporting structures, making them versatile for various construction applications.
• Energy efficiency. The panels’ superior thermal insulation significantly reduces energy consumption for building heating and cooling, contributing to greater energy efficiency.
• Sustainability. Using renewable materials in these panels supports sustainable construction practices, contributing to lower carbon footprints in building projects. Technological advances, such as automation and additive manufacturing, have improved production efficiency, resulting in cost savings and reduced material waste.
• Economic considerations. While advanced manufacturing technologies involve high initial costs, their long-term benefits include reduced labour costs, higher production efficiency, and lower material waste. Comprehensive economic analyses can assist decision-makers in adopting these technologies.

Challenges and research topics include the following:

• Enhanced thermal insulation. Exploring ways to further enhance the thermal insulation properties of wood-based sandwich panels will help maximize building energy savings.
• Fire resistance. Current fire resistance measures, while promising, require further development to enhance the panels’ inherent fire-resistant properties. Developing and testing new fire-resistant materials and coatings will enhance safety.
• Durability. Long-term durability concerns remain, particularly related to exposure to moisture, temperature fluctuations, and UV radiation. Future research should investigate new materials and treatments to improve the long-term performance of wood-based sandwich panels under various environmental conditions.
• Standardization and performance data. Standardized testing and evaluation methods are needed to ensure consistent performance and safety. Additionally, extensive data on these panels’ long-term performance and ageing under varying environmental conditions is necessary.
• Economic viability. Detailed cost–benefit analyses of different manufacturing technologies are needed to determine the most cost-effective methods for large-scale production.

In summary, while wood-based sandwich panels hold great promise for modern construction, addressing their limitations through focused research and practical innovations will be key to unlocking their full potential. This review underscores the importance of these panels in advancing energy-efficient, sustainable building practices and highlights the need for continued innovation to overcome current challenges.