Does Cavity Wall Insulation Cause Problems?

If you’ve been considering cavity wall insulation, you might have done some research into its pros and cons. One of the things you might have heard is that it causes damp and condensation.

We’ll try to bust the myths and give you all the advice you need on whether cavity wall insulation is right for you.

You won’t have problems with damp if you have a clean cavity

You might get damp if you have insulation installed when you don’t have a clean cavity. Usually if you get damp after having insulation fitted it’s because you have lumps of mortar in the cavity. In the trade, these are known as ‘snots’. Nice.

But why would you end up with snots in your walls? When your home was built, mortar could have fallen into the cavity. It rests on the ties so that when rainwater hits the external wall, it penetrates to the snot that’s sitting there. If you didn’t have insulation, it wouldn’t be a problem. That’s because it would dry before it reaches the skin on the inside of your home.

But when there’s insulation in the cavity, it stops any ventilation. So when the rainwater hits, it penetrates to the inner skin, causing a damp patch to form.

How to avoid damp problems with cavity wall insulation

Before you get cavity wall insulation installed, ensure that your insulation company checks that your cavity is clean and that they give you an honest answer before they start.

If you’re unsure about whether the company has given you the right answer, the best way to see if you can trust them is by checking their reviews or getting references from past customers. See our article about how to avoid cowboy damp proofers.

What about condensation?

Condensation occurs when warm air hits a cold surface. A prime example is in your bathroom – think about the condensation that appears on the cold tiles after you’ve had a shower. You’re far more likely to have problems with condensation if your walls are uninsulated.

Most contractors installing cavity wall insulation will use blown fibres as it’s been proven that this is more effective at preventing condensation. This is because blown fibres allow any condensation that builds up to trickle down the wall into the damp-proof course.

What if cavity wall insulation is not for me?

If you’re not sure whether this type of insulation is right for you, ask a reputable insulation company. There are other types of insulation available. And, as 35% of heat is lost from your home through the walls, it’s well worth doing.

Emily Rivers

Emily Rivers is the Customer Experience Manager at Quotatis. She informs customers of the latest developments in a range of products so they can make the best choice for their homes and ensures they get the best out of our service.