Suspended Timber Ground Floor Construction Details

Whether building a ground floor suspended timber floor or a first floor hollow floor we explain the different options and techniques that you can use in its construction.

Suspended timber ground floor construction details. Unlike standard ground floor construction suspended floors are not sitting directly on the ground. The ground should have a layer of concrete poured across and there should be a ventilated gap of at least 150mm between the underside of the timbers and the concrete to prevent moisture. Suspended timber ground floors consist of the finished timber floorboards being attached to floor joists which are suspended above the subfloor of the foundation. 6 3 10 construction of steel framed partitions.

Although timber ground floor construction used to be a popular method today it is not as common as the concrete alternatives. At the turn of the 18th century when construction techniques moved from boarded floors installed directly on the ground to suspended timber floors over a ventilated chamber the innovation solved a significant problem. Previously floor timbers had been prone to damp and rot thanks to their direct contact with the moist ground. Supports underneath the floor are permanent and include sleeper walls or timber props placed at regular intervals.

These floor joists are raised above the subfloor on small supporting walls called tassel walls or sleeper walls. Suspended timber floors need to have spaces underneath ventilated via air bricks through the outer walls and gaps in any internal walls so that the air can move across the building underneath the floors to prevent the build up of moisture in the timber which could lead to fungal attack. This allows air flow and ventilation to prevent the mould and dry rot that would otherwise occur over damp ground. We explain how hollow or suspended floors are made and what the key building regulations that affect them are.

Different types of ground floor suspended flooring. Insulation above slab. 5 1 18 laying the ground bearing floor slab. 3 10 ground bearing floor slab.

5 1 17 ground floor slab and concrete. Suspended timber floor as a requirement of the building regulations the structure should be protected against the growth of weeds and other plant life. Government accredited details developed by bre for local government. Building and understanding a suspended or hollow timber floor.

6 3 9 construction of timber partitions. 2 12 timber suspended floor.