Cavity Wall Insulation Query

greyteam1959

My house was built in 1910.It is brick construction with a cavity and I am considering having cavity wall insulation.
The top half of the house has a coat of render on the bricks and due to the age of the render I am a bit concerned about what might happen when the holes are drilled for the cavity wall insulation.
I have visions of it all dropping off !!!!!!
I have seen several companies doing cavity wall insulation round and about, and they all seem to have a wham bang and off we go attitude.
Am I right to be concerned ???

Tucker

Yes and no.

They will drill through the render to fill the cavity and plug the holes with mortar after. However, if the render is in poor condition to the extent that it will fall off from a few drill holes, it's probably best to consider having it re-done (after the insultion of course).

If the render is sound, you will just need to either tuch up the drill holes with exterior masonry paint or if it's not been done for a while, re-paint the whole render.

fluffymuffy

Another consideration with render is that if there's any water behind it then frost damage is more likely once you no longer have the heat escaping through the walls. A lot of rendered properties were damaged in the recent hard frosts.

I wouldn't let that put me off though.

iamcornholio

If the holes drilled by the installation company casuse the render to loosen/fall off, then the render was already in need of replacement and would be falling off on its own in the near future

The main probelm with filling these holes, is that the mortar used will naturally shrink slightly on drying, and this will leave a slight gap for water to get in and behind the render.

So, make sure to check and deal with this a week or so after the work is done

27col

My house had the insulation installed from the inside. But I was building it at the time. Just a thought for you to consider.