Over the last 10 years there has been a widespread campaign, led by the government, to raise awareness about household energy efficiency. A cornerstone of this campaign is promoting ways to insulate the home and reduce heating bills. With the greatest domestic heat loss being through your walls, cavity wall insulation is actively encouraged through a range of incentives and discounts provided by the government, both through the Green Deal and in partnership with the energy companies.
So far so good. However, in August 2015, BBC News reported that over 1000 local authority homes in Wales needed remedial action because of dampness caused by cavity wall insulation. Apparently, removing the insulation cost around five times as much as the original installation. So what does the London property owner need to know about cavity wall insulation: does it cause damp and is it likely to cost you more money than it saves?
An Honest Answer to a Complex Question
The honest answer is yes, cavity wall insulation can cause damp. So before you have it installed, your property should be assessed for potential damp problems. There are a combination of three factors that can cause this sort of dampness:
- You live in an area of high rainfall and severe wind, meaning that your home is exposed to wind-driven rain.
- There is no shelter from surrounding buildings and trees to protect your home from wind-driven rain.
- The external walls are cracked or have degraded, allowing wind-driven rain to penetrate.
- Thankfully, this combination of factors is quite rare, but strong wind can drive rain through the cracks in your walls and on to the insulation, which acts like a bridge, transferring the moisture to inside walls.
A Revealing Report from Which?
In 2011 the reviews and money saving advice organisation Which? went undercover to investigate the quality of insulation suitability inspections. The organisation’s staff posed as potential customers interested in cavity wall insulation. They invited eight insulation companies to assess an unsuitable property and quote for the work. Depressingly, their findings showed that you can’t always rely on assessors to do a thorough job, and that quotes for the work varied hugely.
The news for London homeowners is fairly positive: your property probably doesn’t experience quite the same extreme weather as buildings in Wales, but we all know that the London climate is becoming more extreme while the housing stock gets older. If you have any concerns about your existing cavity wall insulation, why not book one of London Damp Company’s free damp surveys. Call us for advice on 0207 127 6886.
