When an existing slab (of timber, composite steel beam, concrete or hollow clay block construction) is reinstated it often needs to be strengthened to reduce its deformability, increase its load-bearing capacity, and bring it into compliance with new regulatory requirements or support increased live loads required by the new use of the building (e.g. from residential to retail or office use, or when roof spaces or additional upper floors are brought into use).
One of the simplest and most effective ways of strengthening a slab is to construct a lightweight structural concrete slab above the old load-bearing structure, suitably connected to it and to the perimeter walls.
In effect, this creates a composite slab of mixed construction in which the lightweight structural concrete is the layer in compression and the old structure is mainly in tension.
This method offers many advantages:
Laterlite lightweight structural concretes, suitable for strengthening existing slabs, are available:
For further information, please refer to the specific sections on new-build composite slabs or vaulted slabs.