What is beam floor construction?
Beam floor construction is a traditional floor system in which wooden beams serve as the primary load-bearing elements. The beams run parallel to each other, spanning the distance between two load-bearing walls. Floorboards or sheet materials such as plywood are then fixed across the beams to create the walking surface.
Construction and layout
A beam floor consists of a series of timber joists — also called floor beams — placed at regular centres. The typical centre-to-centre spacing ranges from 400 to 600 millimetres, depending on the load requirements and the span. The beam ends rest in pockets within the masonry walls or sit on joist hangers and bearing plates.
The floor boards or panels are fixed perpendicular to the beams, forming the subfloor or finished floor surface. On the underside, a ceiling finish can be applied, such as plasterboard or timber lining boards.
Application
Beam floors are commonly found in buildings constructed before 1970, but they remain popular in modern timber-frame construction and sustainable building methods. They are used as:
- Ground floors above a crawl space
- Intermediate floors between storeys
- Attic floors beneath the roof structure
During renovation work, beam floors should be inspected for timber decay, insect attack from woodworm or longhorn beetle, and their load-bearing capacity should be assessed by a structural engineer.
Advantages and disadvantages
Beam floors are relatively lightweight and straightforward to modify or repair. However, they are more susceptible to vibration and sound transmission compared to concrete slab floors. These drawbacks can be effectively mitigated with appropriate insulation, resilient bars, and a well-designed floor build-up.
Related terms
- Beam layer
- Beam end
- Single beam layer
- Composite beam layer
- Floor joist
- Timber-frame construction
- Crawl space
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