Unit Overview
Traditional Cavity Wall and Strip Foundation
Raft Foundations and Timber Frame Construction

Traditional Cavity Wall with Strip Foundation

A strip is dug to support the load bearing walls. This must be 150mm wider than the load bearing walls. It is common to use an excavator with a 600mm wide bucket.

The depth of the foundation will vary depending on the load bearing ability of the soil, 2.6m depth is common for a domestic house. Most of the soil will need to be removed from site.


The base of the trench must be level and have square edges, to prevent movement or weakness in the concrete.


Concrete is poured into the base, this acts to spread the load placed on it by the load bearing walls.


A cavity wall is built using a suitable material such as heavy dense block and brick on the outer leaf.


The substructure wall is built up to at least 150mm  above ground level at which point a damp proof course is added.


A beam and block floor is common in traditional cavity wall buildings, this provide a solid feeling floor. Screed and insulation such as foam are added to the floor





Walls are built up using block on the inner leaf and brick on the outer leaf with brick ties being used to increase lateral stability.


Wall openings such as windows and door are left and topped with wither concrete or steel lintels.



The first floor is commonly made from timber joists supported by galvanized steel joist hangers, with a chip board tongue and groove floor added above.


Internal partition walls are created with wither metal or timber stud work, these allow cables and pipes to run internally.


Roofs are either constructed on site with timber rafters, or with prefabricated roofing trusses. These are covered in roofing paper, which is in turn held down with roofing battens. The roofing battens are place at intervals to allow slate or tiles to be nailed into place.


Tiles or slates are added from the base of the roof working upwards, with vertical and horizontal overlaps to ensure the roof is water tight. A cap or ridge stone is held in place with mortar.


Facia and soffit boards are added to seal roof, guttering is added to facia board to help remove storm water from the building.


A variety of windows and doors can be used, ranging widely in materials, windows will have an external cill, will close the gap at the base of a window and have a fall that allows water to flow away from the building.


Insulation to prevent heat loss is added in the cavity of the wall and the loft space.

Internal staircases are generally made from timber, with internal walls and ceilings being finished in plasterboard with several skims of plaster. The plaster board is screwed directly to studs and joists, or bonded to external block work.