Why build a suspended ground floor?
A suspended floor spans between the foundation walls instead of sitting on the ground. That makes it the natural choice where the ground is poor, sloping, made up, or affected by trees and clay that can move with the seasons. It is also the standard choice for most new houses, because it removes the need to fill, compact and blind a large area before a slab can be cast.
With beam and block, prestressed concrete beams bear on the inner leaf of the foundation walls and concrete infill blocks sit between them. Once the joints are grouted the floor is a solid working platform, so trades can get straight on with the next stage.
What goes into the floor
- Prestressed beams made to length for your spans, with the spacing and any doubled beams set out on the layout drawing.
- Infill blocks laid between the beams, with slip or cut blocks to close up at walls.
- Grout brushed into the joints to lock the deck together.
- Insulation and finish: typically rigid insulation with a screed, or a floating board finish, to meet Part L.
The ventilated void
Under the beams there is a void, ventilated through the external walls with air bricks or periscope vents, to keep the underside of the floor dry and to disperse ground gases. Building Regulations guidance generally expects a clear void of at least 150 mm, with more where clay soils could heave. Your layout drawing shows the levels so your groundworker can set the walls to suit.
What you get from us
- A beam layout drawing for your exact footprint
- Structural calculations to support your Building Regulations application
- Beams and blocks delivered to site, with crane offload available
- Answers for your builder or Building Control officer if questions come up