Why air tightness helps us create healthy homes

Britain’s drive towards energy efficiency has created a new question for buyers: are sealed newbuilds with proper ventilation better than older ‘leaky’ homes?

Air tightness and how to achieve it has become a major issue for housebuilders as regulations get tighter to cut energy waste and CO­² emissions.

With the UK having some of the oldest and leakiest housing stock in Western Europe, accounting for up to 30 percent of our energy use according to some reports, we think the push is justifiable.

But it hasn’t stopped doubters expressing concern over whether older, draughtier homes allowing air in through cracks in the building’s fabric are healthier than a new build sealed up to a specified level.

Well, as long as they are sealed correctly, a newbuild should be far and away the better option when it comes to the health of those living there.

Poor air tightness, poor health

The key is to understand the difference between controlled and uncontrolled ventilation. The former ranges from extractor fans in bathrooms and cooker hoods in kitchens all the way up to mechanical ventilation with heat recovery; the second involves trickle vents, leaving windows open or just about anywhere there is a crack or gap that lets in air.

The problem is that with uncontrolled ventilation in older homes, the air travels across a multitude of materials that can pollute the air inside. Walls contain all sorts of things you wouldn’t want to breathe in, from dust to mites to fibreglass. When you add in the issues of penetrating water causing damp and mould it becomes the opposite of a healthy home.

One further issue adds to the confusion: breathability. When people ask for a ‘breathable’ home, what they often mean is that they want fresh air in every room. Many people believe older houses are more ‘breathable’ because they have more gaps in the structure where air can get in. However, this is uncontrolled ventilation with the air working its way in and out through the gaps and cracks in the building – which isn’t clean. Breathability refers to moisture, specifically the speed at which vapour passes through a particular material or construction – just like a Gore-Tex Jacket. The key to a healthy home is having an airtight, vapour-open building structure. Research shows that a 20mm x 20mm hole in the air tightness layer brings 98 times more moisture through the walls than if it was airtight. This is why air tests are important. Read our article on air tests and when they are required for more information.

This can lead to a host of problems for occupiers, from mould and dust mites to aggravating conditions like asthma, as well as wasting heat and increasing utility bills.

Improving air tightness

Traditionally caulk, tape or foam has been used to seal new builds before testing the air tightness but that takes a lot of time. We, on the other hand, are at the forefront of the movement towards high-tech solutions that create a healthy home, using a mist of particles that can plug 100% of all gaps in just a few hours.

One of our operators with a laptop controls the level of air tightness seal required by the contractor so they can achieve – when ventilation methods are taken into consideration – the required certification.

We can guarantee any level of seal, depending on the contractor’s requirements. Combine that with proper ventilation and modern building materials and problems such as damp and mould are consigned to history.