Cavity wall construction – Brickwork outer leaf, tied to block work inner leaf with wall ties and a 75mm cavity. The cavity acts as a water barrier. The properties construction prevents damp by a horizontal damp proof course 150mm above ground level and vertical damp proof courses at openings where brickwork and block work meet.
The main failure with this type of construction is based on poor quality work – this was not evident here. Additional ferrous wall ties can rust therefore it is required that all wall ties are stainless steel and correctly vertically and horizontally spaced.
Cavity walls may be potentially at risk as follows:
Party Wall Surveyor serving Thanet and London
Third Surveyor serving England and Wales