Cavity wall insulation can save homeowners money on energy costs by slowing the rate at which heat escapes a home and decreasing noise transfer from room to room. It may even help prevent future renovation costs!
However, problems may arise when cavity wall insulation is installed improperly or inappropriately in homes which do not suit it or when installation work is performed incorrectly – leading to damage being done to walls as well as possible health risks for residents.
Cold spots
An incorrect installation of cavity wall insulation can lead to uncomfortable cold spots in your home that create discomfort as well as damp or mould issues, incurring costly heating bills as your boiler must work overtime in order to heat all parts of your residence.
Insulation can become damp and sodden over time, allowing condensation to form. This can lead to mold growth as well as serious structural damage in your home, so it is vitally important that quality practitioners install cavity wall insulation.
Problems may also arise if the drill pattern and blowing pressure are incorrect, leading to void spots and the intrusion of moisture into brick walls. When this occurs, insulation needs to be inspected with a borescope before being removed if found damp and sagging – this process should be undertaken quickly by trained professionals.
Damp penetration
Cavity wall insulation can help lower energy costs and make your home more comfortable, but only when installed properly. If the insulation becomes saturated with dampness it could actually increase heat loss rather than decreasing it.
Damp penetration occurs when wind-driven rain enters through gaps left by brick ties and obstructions in the cavity, entering through gaps created by obstructions within that space and reaching into its inner walls of a building through cracks left between brick ties, creating damp patches or even rotting skirting boards in its path.
This issue is most prevalent among homes retrofitted with CWI that have been installed in areas subject to high rain levels, according to guidance that suggests such buildings aren’t appropriate for cavity wall insulation and require an in-depth survey prior to any works commencing.
Corrosion of wall ties
Wall ties (also referred to as masonry ties or anchors) are essential parts of brick walls and should never be neglected when maintaining them. Constructed of metal, these wall ties can become susceptible to corrosion due to being located within walls where moisture collects; when corrosion does take hold it can cause expansion in the tie’s material and support no longer exist resulting in structural failure and ultimately collapse of an outer leaf wall if left untreated.
Mild steel fishtail or galvanised wire butterfly ties often corrode when exposed to moisture, with expansion being the likely outcome. This phenomenon is most likely to happen where they’re situated beneath an eaves, gable or purlin and in areas like behind openings where dampness remains for extended periods.
Corroded masonry ties can sometimes be seen through inspection holes; however, more often they need to be detected using a boroscope used by our surveyor to clear away insulation and view metal surfaces. Corroded wall ties will look dull silver in colour with significant areas missing their galvanised coating.
Poor U-value
U-values provide an important indicator of heat loss from buildings. Calculated by adding up each material’s thermal resistance value, U-values serve as an integral measure for measuring heat loss from structures built or renovated according to building regulations/standards that stipulate certain U values must be achieved for renovation or new builds.
Insulated cavity walls typically have lower U-values than solid brick walls because the gap between inner and outer layers of bricks acts as an insulator, keeping heat inside rather than escaping through walls. This enables homeowners to retain more of the heat generated from radiators.
However, even with low U-value insulation in its cavity walls alone it may still fail to meet SAP assessment standards because airtightness of a house is also essential to keeping heat inside.