Full Fill

Full fill cavity walls, where the insulation fills the whole cavity, are widely used on UK new builds and extensions. This category covers full fill masonry details from foundation and ground floor junctions through window heads, cills and jambs to eaves and roof junctions. It includes wide-cavity details, house extension wall types and Porotherm clay block walls. Use them as a starting point and check insulation thickness against your U-value calculations and site exposure.

Is full fill suitable for every location? Not always. Where walls face severe wind-driven rain, partial fill or other measures may be more suitable. Check Approved Document C and the insulation manufacturer’s guidance for your site.

Are there extension details? Yes, including a set of full fill extension details that combine different wall, floor and finish types.