Archive for Breathable Walls

Breathable Walls

Bricks are ideal as a building material as they allow moisture vapour to pass through them and so allow our homes to breathe. However, solid 9 inch walls are also amongst the coldest found in any type of construction and especially when the outer bricks have been exposed to over 75 years of the UK’s varied climate. The effects of hot sun and wet frosty nights degrades the front face of the brick and leads to spalling . This is when the outer most protective layer comes away from the brick .

This then exposes the highly porous heart of the brick and can lead to water ingress, penetrating damp and condensation damp and a lot colder internal temperature. Naturally the responsible home owner wishes to prevent this so decides to cover the outside wall to protect it from the weather. This is often a case of making things worse not better if a cement render or the wrong paint is used.

If not carried out properly using the correct materials adding a layer to the outer bricks can seal them and stop them from breathing. This will make the damp far worse and will eventually lead to the cement render covering or the paint covering splitting and cracking open. This of course just allows more watewr into the wall when it rains and exacerbates the situation.

blown paint from trapped moisture

It is therefore absolutely vital that any paint covering, rendering or insulation that is put on a wall is microporous. This means the material is able to repel water whilst simultaneously allowing moisture from inside to escape to the outside. In other words it acts like human skin in that we can have a swim in without our bodies absorbing the water but when we get hot our skin is able to let the sweat and moisture come out of our bodies.

Our homes are full of moisture generating devices such as heating, showers, washing machines, cookers and kettles etc so it is vital we ensure the fabric of our homes can allow this moisture to pass to the outside and keep us dry and warm inside the home.

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