Cavity Wall Insulation

About

What is cavity wall insulation? Most UK homes built after the 1920s have cavity walls: two separate leaves of brick or block with a gap, the cavity, running between them. That gap was originally designed to keep rain and damp out, but left empty it also lets a lot of heat escape. In fact, around 33% of the heat lost from an uninsulated home goes straight through the walls. Cavity wall insulation fills or lines that gap. It works by trapping air within the insulation material and slowing the movement of heat from the warm inside of your home to the cold outside - a bit like putting a lid on a hot cup of tea. The result is a warmer, more comfortable home, lower heating bills and a lower risk of condensation and damp on your internal walls. The benefits of insulating your cavity walls Lower energy bills - with far less heat escaping through the walls, your home stays warmer for longer and your heating can work more efficiently. A more comfortable home - fewer cold spots and draughts and more even temperatures from room to room. Damp and condensation control - the right insulation, correctly fitted, helps keep moisture out of the inner wall. Better sound insulation - mineral wool in particular adds useful acoustic performance as well as warmth. A long-life upgrade - properly installed cavity insulation is designed to last the lifetime of the building with very little maintenance. Types of cavity insulation There are two main approaches, and this collection covers the boards, batts and slabs for both. Full fill cavity insulation fills the whole cavity, sitting tight against both leaves to form a continuous layer of warmth with no gaps. It’s widely used for new builds and extensions. Mineral wool cavity batts are the most popular full fill option - non-combustible, budget-friendly, and flexible enough to fit snugly around wall ties, while rigid PIR cavity boards give you a better U-value from a thinner board where cavity space is tight. Partial fill cavity insulation uses