Cavity Block Insulation

Renno123

Hi I have an old cavity block extension which is freezing!!
I would like to insulate it.
has anyone insulated their cavity block walls using spray foam insulation?
if so, have you noticed much of an improvement?
i am aware of the thermal bridge issue but wondering how much heat would escape?

this would be the easiest option for me, as dry-lining would involve re-tiling bathroom etc..

thanks

MicktheMan

Renno123 wrote: »

i am aware of the thermal bridge issue but wondering how much heat would escape?

Pretty much all of what is currently escaping

Not really diy but Ewi is your only option imo

BIGT4464

external insulation is what you are looking for. Pumping the cavity with beads made very little difference to my parents place. If you cant dryline inside its ok, but it would be good to do this too.

listermint

If it's cavity block rather than cavity wall pumping is a non runner.

You have to externally insulate or you have to internally insulate. They are your two options

Renno123

Thanks.
Ideally i would like to insulate externally. i imagine it is the most expensive option but will get a few quotes,
I saw one or 2 companies offering cavity block spray insulation and wondered how effective it would be or a waste of money.

whizbang

Apparently its now necessary to externally insulate also, with full water ingress protection, if you are filling the cavity.

Otherwise external insulation on a cavity block wall is useless, unless you follow the insulation right over the roof, connected on all sides, so the cavity remains inside the envelope.

In most cases, the cavity is probably full of holes (especially in a kitchen), which just sucks the heat straight up into the roofspace, which I presume is a cold roof.
So you should really consider the cavity as open to the elements.

listermint

Renno123 wrote: »

Thanks.
Ideally i would like to insulate externally. i imagine it is the most expensive option but will get a few quotes,
I saw one or 2 companies offering cavity block spray insulation and wondered how effective it would be or a waste of money.

It's a waste of money. And frankly a spoof.

I wouldn't get it done for a tenner

Sleeper12

Renno123 wrote:

Thanks. Ideally i would like to insulate externally. i imagine it is the most expensive option but will get a few quotes, I saw one or 2 companies offering cavity block spray insulation and wondered how effective it would be or a waste of money.

Waste of money

BryanF

Cavity block https://www.build4less.ie/cavity-block-9-440mm-x-215mm-x-215mm.html

Cavity wall : Block/ cavity/ block https://en.m.wikipedia.org/wiki/Cavity_wall