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Preventing condensation is better than the cure

The dangers of Damp and Mould 

By Wendy Thomas, Residential Product Manager, November 2014

The dangers of damp and mould spores caused by condensation are very real, and as winter approaches social housing tenants living in poorly ventilated homes will be at risk of developing or worsening a range of allergies, from asthma to rhinitis.

Faced with energy price hikes and more severe winter weather, tenants are less likely to open windows and dry clothes outside and so the damage caused by condensation remains. As autumn approaches and the temperature drops, many Registered Social Landlords will start preparing for the onslaught of tenant complaints about damp walls, condensation on windows and the appearance of black mould on fabric, clothing and wallpaper.

Condensation dampness affects both new and older properties and is much more common than you might imagine. Excess moisture is produced simply by breathing and by everyday activities like bathing, cooking, washing and drying our clothes. An average family can produce up to four pints of water per day and this moisture is absorbed into the air where it migrates through the home and condenses on cool surfaces such as windows, mirrors, wall tiles and furniture.

This humid environment is the ideal condition for mould spores to germinate and grow, and for dust mites to breed. These allergens can aggravate asthma and trigger allergic symptoms such as rhinitis and eczema, so while your property may be subjected to cosmetic damage caused by excess humidity, the health and wellbeing of your tenants will also be at risk. In short, condensation dampness is bad news for all concerned.

For many RSLs, this problem comes around every year between autumn and spring, bringing with it visits from surveyors and damp assessors, and costly repairs to the building fabric and decoration. Many will try to encourage their tenants to adopt lifestyle changes to lower the level of humidity in the property: opening windows and closing doors in moisture-producing rooms, keeping the property warm to reduce cold spots, and not drying clothes inside. In reality, as a result of fuel poverty and more extreme weather, it is often difficult to enforce these changes and when outside temperatures plummet any activities that result in a loss of heat and increased fuel bills are quickly abandoned.

So what’s the solution?

Trawling the internet for advice on tackling condensation will uncover a plethora of so-called cures, but be wary: many of these are simply short-term solutions that will mask or target only the cosmetic appearance of mould without actually dealing with the root of the problem. Anti-mould paint, dehumidifiers, cavity wall and loft insulation, draught-proofing and installing double glazing are just some of steps suggested by retailers and suppliers. Some are extremely costly, others are effective for tackling penetrating damp, but none of them will solve the condensation issue. It’s a matter of adequate ventilation. For properties badly affected by condensation dampness, the most effective solution is a whole-home ventilation strategy called Positive Input Ventilation, sometimes referred to as Positive Pressurisation or PIV.

Ventilation manufacturer, Nuaire invented the technology over 40 years ago in conjunction with the North Eastern Gas Board which sought a low-cost solution to clear condensation and humidity caused by sealed up chimneys and modern central heating systems. Today, PIV is the most popular method of whole home ventilation in the UK, being simple to install and still providing the only known cure for condensation dampness and the associated health issues caused by dust mites, mould spores and other indoor pollutants.

The PIV process involves drawing fresh air from outside into a fan located in the loft area. The air is filtered, tempered using the heat that naturally accumulates at the top of the house, and then gently pushed into the home causing positive pressurisation. By continuously supplying fresh, filtered air through the home, the moisture-laden stale air is forced out through the natural leakage points. As a result, the humidity is drastically reduced and the allergens are removed from the air creating a fresh and healthy indoor environment for tenants. Quiet and energy-efficient in their operation, Positive Input Ventilation systems can reduce the overall maintenance costs of a property by protecting the fabric and materials in the home and preventing the build-up of tell-tale signs that often trigger tenant complaints. This strategy is extremely cost effective and quick to install compared with other ventilation strategies such as installing individual extract fans in all wet rooms. This makes PIV ideally suited to repairs and maintenance projects, yet it is gaining popularity in new build homes.