What can go wrong after installing External Wall Insulation?

In this blog, we are going to look at some of the most common problems we see on installations and how you can avoid them!

1 . Silicone Sealant on EWI

We have noticed that the biggest problem after installing EWI is silicone sealant.

When silicone sealant is used around windows or verges, it can degrade quite quickly. Even the best silicone sealant will fail if continually exposed to water, and this can lead to damp problems internally. You should try to minimise the use of silicone wherever possible by the use of appropriate beads and trims wherever you can, but you may need to reseal any silicone you have installed every few years.

2. Cracks and mechanical damage

It is quite unusual for cracks to appear on the wall of their own accord, but we do sometimes get customers calling because they have accidently damaged the render.

One customer actually drove their car into the wall whilst parking! In this case you need to contact us within 48 hours of the incident and we can then look to resolve the situation.

A patch is always possible, and usually not particularly difficult, although it will likely leave a scar in the top coat even with the best workmanship.

3. Render is getting dirty and green on solid wall insulation

Especially in gardens, it is not uncommon for the wall to discolour to a green colour on some EWI jobs.

This is usually down to the type of render used and not the application.

Cheaper acrylic renders are especially prone to this form of discolouration, as they tend to collect dirt more than a silicon render. Silicone render is self-cleaning, meaning that water does not sit on the wall like it does with acrylic – water will run off, helping to keep it clean and prevent the build up of biological matter.

If you have acrylic render it is recommended to jet wash regularly and in some cases it may need repainting. If you are yet to install your system, consider using a render with a biocide mixed into the top coat. This will help prevent the growth of any organic matter on the wall.

4. Ventilation issues

We always extend ventilation ducts, but you will see some installers covering them up. The vents are there for a reason!

Covering the vents can cause damp and condensation build up, so ensure your vents are open and if draughts are an issue,

look at modern ventilation boxes which will reduce any draughts whilst still allowing air to circulate.

 5. Do not plant any plants next to external wall insulation

Any plants should be kept at least 10 inches away from the wall, which will help prevent any dirt or organic material building up on the wall.

Plants covering the insulation will also prevent the self cleaning properties of the render from taking place as usual.

As well as plants, you should not grow any creeping plants or climbers on the wall. This can cause stress to the system as it grows and can cause cracking. If plants are grown up the wall it may affect your guarantee.

There are some other issues that may arise, but these are some of the most common.

These problems can be the result of poor installation or poor upkeep by the customer, but either way, most are resolvable situations, so please talk to your installer to get further advice. We also carry out regular remedial works, so if you wish to get a quote to fix your render system, just give us a call.