Cavity wall insulation

c class 226

Hi folks
My first ever post so apolgies if this question has been asked before.
I recently got a quote to have foam insulation pumped under pressure into a standard concrete block cavity which already has aeroboard insulation in it. Does this work ie. does it fill all the small spaces as promised; can it cause damage to the walls ( its to be pumped in at 120 lbs/in2); I read somewhere recently that this type of product has not been certified by the Irish Agrement Board. Does this mean I should run a mile from it?

sinnerboy

better to use polystyrene beads
expanding foam if it goes wrong ( fails to set ) cant be undone

Ashfield

Im going to be pumping the beads into our walls, was thinking of filling the cavity with kingspan boards but they wont cover all the cavity space,
from what ive heard the beads are well worth it.

Villain

They both give the same U values from what I have read.

c class 226

Hi folks
One of the selling points for the pumped foam is that it will fill all the gaps, spaces etc in the cavity as it is being pumped in under pressure. Are the beads as effective? I suspect there are cold bridges and gaps in the existing insulation.

sydthebeat

if the foam system isnt certed for walls then i wouldnt use it. You would get a very similar result using a certed system like rockwool 'energy saver'.

ardara1

If the gap is less than 50mm they're not allowed to pump it.

c class 226

Hi
Is there in fact anything I can do to improve the insulation? The two bedrooms that I am mainly concerned about are cold and one of them has an amount of mould growing on the walls which I presume is condensation from cold spots on the external wall. There is a standard 100mm cavity with 40 - 50 mm aeroboard in it which would appear to have cold bridges in it.

sinnerboy

beads . they will fill in large gaps in aerobaord , as well as air cavity

muffler

To the best of my knowledge there is no cavity insulation that has been approved yet that will compliment an existing cavity containing rigid board insulation. Probably better insulating internally.

c class 226

Hi folks
Thanks for replies