Awaab’s Law which compels social landlords to address damp and mould, is likely to be extended to private landlords next year; however, it’s important to recognise that the issue is not confined to rental properties – it affects new builds too. Here Brian Adams, senior director of international business at Arclin looks at how integrated weather resistant barriers can help prevent damp in timber frame homes.
News headlines about damp and mould have mainly focused on social and private rental. For example, the Citizens Advice found half of all private renters live in homes “plagued by cold, damp and mould”. However, evidence presented by The New Homes Ombudsman Service to the Housing, Communities and Local Government Select Committee inquiry into Housing Conditions in England stated there were a steady number of consumer complaints about damp and mould in new build homes. This is echoed by the English Housing Survey (EHS), which found that 5% of all dwelling types in England had a problem with damp.
If homeowners flag issues with mould and damp within the first two years of occupation, it can be a major issue for developers. Damp and mould can be a difficult issue to fix, and the developer can become locked into costly cycles of investigation trying to find the root cause of the issue.
The longer the problem continues the more damage could be done to the property and the greater the health implications for residents. Over time, damp can cause wood to rot impacting the structural stability of the timber frame home. It can also reduce the effectiveness of certain types of insulation, making the home colder and more susceptible to interstitial condensation. While mould can cause or worsen respiratory illnesses, including asthma, wheezing and breathlessness, and allergic reactions.
If damp and mould continues without resolution, it can lead to warranty issues, and unresolved disputes could lead to legal challenges – which in turn can damage the developer’s reputation.
Poor installation practices can contribute to damp
The housebuilder’s responsibility lies in preventing issues that can cause damp during construction. According to the evidence provided by The New Homes Ombudsman Service, one cause of damp and mould in new build homes is poor storage of building materials. Failing to properly protect timber products on the way to or on site risks them being exposed to rain or snow, or standing in water, possibly continuously for days at a time. If they aren’t dried thoroughly before use, moisture is likely to be trapped within the construction.
Another cause is the failure of moisture control solutions due to mishaps during installation and construction. Timber frame homes are traditionally protected from water ingress by plastic-sheet products called housewrap. This must be nailed and stapled to the timber frame by experienced installers. To be effective the wrap must be staggered to prevent coinciding joints, laps must go in the right direction, and tricky installation details must be undertaken around window and door openings.
Even when housewrap is installed in a factory, it can be inadvertently damaged in transit, or by other trades as they install services or undertake other phases of the build. These minor nicks and tears in the housewrap that seem minor can become full scale rips as soon as the wind gets up – and even small tears risk moisture being able to penetrate behind the wrap and into the frame structure.
Overlay solutions protect wood before it even arrives on site
The answer lies in new technology that enables integrated weather resistant barriers, such as Arclin’s Arctek® Dryshell™, to be fused to OSB sheathing boards. Integrated weather resistant barriers help reduce the risk of moisture penetrating timber panels during construction, whilst vapour permeability allows incidental vapour to escape the building envelope to avoid interstitial condensation.
The overlay is a continuous, factory-applied solution ensuring a consistent quality of installation due to a factory-controlled environment.
This means timber frame walls and roofs, SIP systems and cassettes arrive on site with a durable, airtight and windtight layer already in place. It makes protecting the wood from wet weather onsite before installation and during construction easier. It also helps minimise the risk of damage during transportation or installation which can compromise performance.
Shifting to factory-applied, integrated weather resistant barriers means there’s less reliance on accurate installation and helps mitigate the risk of accidental damage to the vapour control layer during installation and construction. This means housebuilders can be confident that weathertightness will be achieved quickly and effectively, and homeowners can enjoy comfortable, warm homes that are free from damp and mould.