Internal walls can be constructed of timber, metal frame or masonry. Whether these ‘partitions’ are load-bearing or non-load bearing, they need to be appropriately supported. We take a look at the support requirements of non-load-bearing block partitions.

So what do we know about non-load bearing walls?

Non-load bearing walls separate rooms within a house and can be altered or even removed completely without weakening the structure of the building.

Even though they support their own load, i.e. the weight of the construction and any finish, non-loadbearing walls must be adequately supported and restrained at the top and where particularly high, throughout the height.

The question of whether non-loadbearing block work partitions can be built on ground bearing slabs is often the subject of debate. Generally it has been accepted that these partitions can be supported by a structural floor, but not a floating floor that incorporates a compressive layer, i.e. a screed over insulation – in this case the wall should be supported by the structural floor.

Non-load bearing block partition requirements

All loads in a building have to be taken down to a sound foundation and the ground around the foundation must not be over stressed or be subject to undue settlement resulting from this loading. In the case of non-load bearing partitions built on the ground-bearing slab, the slab acts as the foundation.

The external foundations of low rise housing with ground bearing slabs will typically carry loads of between 20 and 50 kN/m run of wall (2 to 5 tonnes/m). The load from a single storey non-load bearing block work partition that is 100mm wide, is likely to be much lower at about 4 kN/m run (0.4 tonnes/m run).

If an external wall requires a 500mm wide strip foundation to safely support say 40 kN/m then the non-loadbearing partition would require a footing one tenth of this width to induce a similar stress in the supporting ground from its load of 4 kN/m run – however this would not be a practical dimension and depends on a number of assumptions. Consideration should be given where walls are supported on concrete slabs, that the slab is supported on crushed stone uplift as well as considering the ability of the slab to resist the forces imposed by the wall.

So what can we learn from non-load bearing block partitions?

Where the non-load bearing partition joins the external load-bearing wall, this relatively small load can generally be safely carried by the slab without over-stressing or causing undue settlement of the supporting ground and without causing problems associated with differential settlement.

Where masonry partitions are concerned, these should not be built off timber joists. Manufacturers of precast concrete beams/slab floors should be consulted and a specification issued if carrying masonry construction.

By Frzana Ferguson