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What's THE most important consideration when installing Cavity Wall Insulation?

You may have heard some horror stories about Cavity Wall Insulation or seen some shocking images on Google (as shown).

If installed incorrectly or if the property is not suitable for Cavity Wall Insulation the results can be disastrous, including:

  1. Damp patches
  2. Condensation
  3. Black mould
  4. Even cracks in the wall, resulting in structural damage!

So what is THE most important thing to consider when installing Cavity Wall Insulation?

Answer: The condition of your walls.

The effects listed above can all result from an issue with your walls; in short, if there are cracks or weak spots, water can infiltrate the walls, resulting in the cavity insulation absorbing moisture. This moisture is trapped in the cavity, causing damp and eventually mould to grow on the interior wall.

If the insulation material expands too much due to changes in humidity, it can exert pressure on the wall, leading to cracks, especially if the wall is old or already weak in places.

Problems, issues with Cavity wall Insulation - damp, condensation, mould, wall cracks

Does this mean you shouldn't get Cavity Wall Insulation?

No, this does not mean you shouldn’t get Cavity Wall Insulation; it just means you must work with a professional installer who understand how to mitigate these risks.

How to mitigate the risks of Cavity Wall Insulation

  1. Check walls thoroughly prior to installation.
  2. Fix any weak spots and cracks.
  3. Use an accredited cavity wall insulation installer – the insulation must be spread evenly, with the correct amount of pressure, using high quality materials.
  4. Select an installer that has in-house rending/coating services. Finish the job with one of the following:
    An external wall coating, that will protect and weatherproof your walls.
    Fresh render to seal and protect your walls.
    Reparation of any issues in existing render.
    Spray Cork Insulation on exterior walls – see here for more information.
  5. Lastly, make sure you have a guarantee.  Why would you not go with an installer who offers a free 25 year guarantee, over an installer who does not?

Our Process

If you’re based in South East England then we’d love to work with you to safely install Cavity Insulation into your home. This is what you can expect from working with ProGuard Exteriors.

Free Property Survey

This informs us of any issues with the walls that need to be addressed. As well as what existing insulation is present, the size of the wall cavities and other factors.


With the survey data, we'll then recommend the best solution for your property, along with a detailed quote. This is still all free of charge.

Installation Service

On quote approval, our accredited installers will implement the insulation and any additional rendering or wall coatings required.

25 Year Guarantee

On completion, every Cavity Wall Insulation customer receives a Free 25 Year Guarantee.


Book in your Free Cavity Survey

Join our happy customers – see our 5-star rated Google reviews.

5-Star Google Reviews