Cavity wall insulation - worth it or not.

[piper64]

About 6 years ago, I had wall insulation put in by Millfold as part of a Warm Front scheme, which meant it was a reduced cost.

I have never felt ANY benefit of this work since and seem to suffer patches of black mould where the ceiling meets the wall, possibly due to Millfold sealing all the external airbricks.

I don't believe that the insulation was correctly applied, which I took up with them at the time and received a further discount with their insistence that the job was done to specification. The job was supposed to take 10 bags, yet they left with 5 still on the wagon. They also left a hell of a mess which I had to clear up, rockwool everywhere.

Each time I can see into the cavity, such as sinking in new sockets, I can barely see any trace of the insulation, just a few wisps like a spiders web.

British Gas are offering an insulation check, whereby they use a resonance device that tells them the density of the insulation. I'm going to book up a check, but is there any benefit to having wall insulation done as many people on the web say 'don't bother'.

I'm wondering if they have all been the subject of the practice of 'pretending' to fill the walls or is there anyone that has noticed a benefit?

 

[AronSearle]

It does make a difference, not a huge one, but a noticeable one.

I have never felt ANY benefit of this work since and seem to suffer patches of black mould where the ceiling meets the wall, possibly due to Millfold sealing all the external airbricks.

Probably left some parts of the wall uninsulated, so still cold + they have reduced the ventilation = more moisture.

EDIT = Should also clarify, that you have your loft insulation, and wall insulation, if these do not lap at the ceiling to wall junction = cold bridging = condensation = mould.

 

[piper64]

Thanks.

I'm going to pick out the silicon that was pushed into the airbricks, that should help ventilation then.

Regarding lapping of wall insulation and loft insulation in the loft, as the wall insulation is virtually non existent it most likely doesn't lap anywhere.

The upstairs ceilings in our house are angled where they meet the outside walls, the ceiling height invades the roofspace in effect, which means that the roof tiles have a small gap of the width of a roof support between them and the ceiling. About 4 inches.

This small area may not be insulated at all, I have never checked.

For the time we lived in the house BEFORE wall insulation, mould was never a problem though, which is why I'm suspecting it as the culprit.

 

[Nige F]

Thanks.

I'm going to pick out the silicon that was pushed into the airbricks, that should help ventilation then.

For the time we lived in the house BEFORE wall insulation, mould was never a problem though, which is why I'm suspecting it as the culprit.

Clearing the airbricks will be the answer

 

[theoldun]

Clearing the airbricks will be the answer

What do you reckon Nige. A job for Lady Penelope, Virgil in Thunderbird 2 or Dopey Dog.
Regards oldun

 

[piper64]

A joke I'm missing

 

[Karis]

Aftermarket cavity wall insulation is vastly overrated IMO & can cause more problems than it’s worth on older properties. The surveyors (& use the term loosely) don’t understand the potential problems which, for various reasons, can occur & the installation companies are not in the slightest bit interested as their only aim is to secure the government grant they get for dong the “insulation” work

My 1968 property has no cavity insulation & will remain so as long as I own it. The increase in thermal efficiency you will get will have a minimal effect on your annual energy bill &, when you consider the potential problems it may cause, your better off making thermal improvements elsewhere.