Most homes built from the 1930s onwards use cavity wall construction, two separate leaves of masonry with a gap (the cavity) between them, which is far more effective at keeping moisture out and heat in than the solid brick walls common on older properties. Cavity wall work covers everything from building new cavity walls on an extension to repairing problems with existing cavity construction.
Outer leaf – typically brick, forming the visible exterior finish and matched to the existing house on extension work
Cavity – the gap between the two leaves, filled with insulation to current building regulations thermal standards
Wall ties – metal ties spanning the cavity, connecting the inner and outer leaves so the wall acts as a single structural unit rather than two separate skins
Inner leaf – typically lightweight block, plastered internally
Failed or corroded wall ties – older wall ties, particularly in properties built before more corrosion-resistant materials became standard, can rust and fail over time, which can allow the outer leaf to move independently of the inner leaf and, in severe cases, lead to visible bowing or cracking
Cavity wall insulation problems – older retrofitted cavity insulation can sometimes fail or settle, reducing its effectiveness, and in some cases can contribute to damp if installed poorly or if the cavity wasn't suitable for it in the first place
Damp bridging the cavity – debris ("mortar snots") left in the cavity during construction can create a bridge for moisture to cross from the outer to inner leaf
Every extension we build to modern standards uses cavity wall construction, with insulation specified to meet current building regulations thermal performance requirements. This is one of the more straightforward parts of a build to get right, provided wall ties are correctly spaced and installed, insulation is fitted without gaps, and the cavity itself is kept clear of mortar debris during construction, since a poorly built cavity wall can undermine its own thermal and weatherproofing performance regardless of how good the materials specified are.
Cavity wall construction is standard on every extension we build across York and North Yorkshire, and we also investigate and repair problems with existing cavity walls, including corroded wall tie replacement where needed. Every quote is clear and written, and the work is covered under our standard project insurance.
Excellent job from Phil and his team. Both external and internal works finished to an excellent quality. Happy to deal with changes and kept us informed on a day-to-day basis. Definitely recommend.
RW Builders directly on 01904 530941 to discuss cavity wall work for your property. Quotes are free and come with no obligation.