Foam Cavity Wall Insulation Problems

A cavity wall is a double layered masonry wall on the exterior of a home.

Foam cavity wall insulation problems.

Spray foam insulation is a better insulator than mineral wool loft insulation as you need less of it to get the same insulating effect. Yes you can use expanding foam insulation in cavity walls. Cavity wall insulation can cause damp. When we went undercover to investigate the quality of insulation suitability inspections in 2011 our findings suggested that you can t always rely on assessors to carry out thorough inspections or warn of potential damp problems even those from big brands such as marks spencer npower and tesco.

Damp walls as one of the most well known problems with cavity wall insulation damp is an issue that no homeowner wants to see. So how is cavity wall tie failure linked to problems with cavity wall insulation. Spray foam installers missed some of the air leakage sites. When retrofit cavity wall insulation is installed into a property that is located or built in a way that means it should not have the cavities filled or if the work is undertaken incorrectly the first and most obvious sign of a problem is almost always internal dampness.

However if moisture is getting into the cavity the insulation can hold that moisture against the metal wall ties and speeding up the rusting process. In some cases the damp and mould resulting from cwi can cause health problems or exacerbate existing conditions particularly respiratory conditions. Find out if your home s likely to be affected. Remove the foam to reinsulate.

In order of prevalence here are the problems i ve seen with explanations following the list. If left unaddressed long term it can lead to all manner of problems include mould and mildew. Spray foam isn t thick enough. So here s the part that sucks for me what has to be done to fix the problem.

Until the recent fad for cavity wall insulation took hold the only times rainwater penetration was a problem was when the steel wall ties were dirty with mortar droppings and or built sloping downwards from outer leaf to inner leaf or the cavity itself was blocked at low level with mortar droppings or other debris. Expanding foam insulation has increased in popularity as the manufacturers have praised its uses and abilities and its applications have reached to include cavity walls. Remove enough siding to jimmy the foam out probably 2 3 pieces per story per wall cavity. I ve seen a number of houses with problems even though they re insulated with spray foam.

Better yet remove it. Reinsulate with dense packed cellulose still my personal. What is a cavity wall.