Box construction (also called cross-wall construction) is a building system in which walls, floors and roof together form a closed ‘box’ that acts as a single structural unit. The walls and floors work as diaphragms, giving the building high stiffness and good resistance to horizontal loads such as wind.
How does box construction work?
Unlike skeleton (frame) construction — where columns and beams do the structural work — in box construction the walls themselves are load-bearing. Walls, floors and roof form one stiff whole. The behaviour resembles a cardboard box: as long as all walls are in place, it is strong; remove one and it folds.
Key features of box construction:
- Load-bearing walls — often of concrete, calcium silicate or cross-laminated timber (CLT)
- Rigid connections — walls, floors and roof are rigidly joined
- Diaphragm action — floors and walls act as shear diaphragms transferring wind loads
- Compact — efficient use of material
Applications
Box construction is commonly used for:
- Housing — especially terraced houses and apartments
- Tunnel-form construction — walls and floor cast in one pour
- Precast concrete construction — prefabricated ‘cells’ stacked together
- Cellular construction — e.g. in hotels or student housing
- Modular construction — module-by-module assembly
Advantages
- Fast construction time — especially with tunnel formwork or precast
- Good acoustic performance — due to wall mass
- Robust structure — low sensitivity to wind loads
- Fire resistance — concrete and calcium silicate walls are fire-rated
Drawback
- Limited flexibility — load-bearing walls are hard to remove, which makes later alterations difficult
Related terms
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