Installing insulation during house extension

We get asked this all the time. Is cavity wall insulation ever worth installing? Does it work? Does it always cause a problem?

Like so many things the answer isn’t quite as clear as ‘yes or ‘no’ – if only!

Cavity insulation is really effective, reduces energy consumption, makes homes warmer, cosier and cheaper to run…most of the time.

In short cavity wall insulation works well, but not all of the time.

So how does it work?

The way heat moves means that if your room is warm but it is cold outside, heat will move through the wall, cooling the room until a balance is reached – in effect the room becomes as cold as outside! It’s why you can’t heat a room and then turn of all the heating, there is always heat loss.

That’s where insulation comes in. Filling the wall means heat travels out more slowly so consequently, less heating is needed to keep the room at a nice temperature. It’s the same reason we wear a coat on a cold day. Simple!

So if you would always wear a coat in winter, insulation must be a good thing right?

Well, yes – but only under the right circumstances.

Some homes are naturally prone to water ingress. Perhaps the pointing isn’t up to scratch or the bricks themselves have become porous and allow rain water to soak through (this is especially common in areas exposed to the elements such as coastal or hilly locations).

In these homes insulation can become damp and stop the insulation from working, rather like a wet coat in winter that wouldn’t keep you warm.

Dampness can seep through to the inside of the house looking unsightly, cold and causing mildew and condensation issues.

If this happens there is no choice but to extract it, allow the brickwork to dry and then consider re-insulating. However you should only do this once the underlying problem that caused the damp issue has been resolved.

In our experience most of the people who have had extraction work carried out don’t go on to re-insulate simply because they are fearful of the same terrible problems returning. However, it is possible and there are a range of products developed in recent years that can make it perfectly viable, from water repelling masonry creams to water resistant insulation.

If you are concerned about dampness in your property and think it might be caused by the insulation we are always on hand to offer help and advice. Don’t hesitate to get in touch by calling 01903 331 578.

You might also be interested in...

Does cavity wall insulation actually work?