Cavity Wall Insulation - Are the damp issues actually that common

wiftedife

I'm looking at having cavity wall insulation installed. Given that the internet seems to be awash with stories of this causing damp issues, and costing tens of thousands to have removed, I'm very nervous to go ahead with this.

Given the current price of energy, and my living room seems to be constantly cold and struggles to retain heat, I need to do something before next winter to address this.

On almost all threads there is always someone who says that they've had expensive headaches as a result of having this installed but I cannot work out if this is a few people who are quite (for obvious reasons) loud about it or if this really is something to be concerned with.

Are the damp issues actually a common problem? Should I be nervous about having CWI installed?

On another note, those who have had it installed. Does it actually do much to help retain heat?

stuart45

The problem is that you will get a lot of different opinions about CWI, so it's different to really know. 
I know a few people personally who are delighted with it. Others you read about have had problems. 
If you don't have any walls subject to heavy, driving rain, the cavities are clean, at least 50mm and walls in good condition it should be OK, provided it's installed properly.
It has been known to cause problems when voids have been left, or has slumped in places. 
I used full fill insulation in the cavity when I built my extension.

FreeBear

Another issue to watch out for, particularly with older properties - Often, there is no duct linking internal/external air bricks that ventilate the void under a suspended timber floor. Pump the cavity full of insulation, and the air bricks get blocked.

Had rockwool blown in to my cavity quite a few years back. Did little to improve the warmth of the house or cut down on fuel bills. I have since been going round plugging all the draughts as I locate the source. Along skirting boards, gaps in the floor boards, badly fitted windows, etc. This exercise has made a huge difference since I started.

wiftedife

stuart45 said:

If you don't have any walls subject to heavy, driving rain

What defines heavy driving rain? It's all relative so it's tough to know if this will actually be a problem for me. What I think is on my side, is that the outer brick wall of my house is clad in a screed/cement and then painted over. I can't really see rain getting through a layer of pain, screed, brickwork, insulation, and then block work.

It is a bit exposed at the bottom, but this is below floor level so I'm hoping that shouldn't be a problem.

wiftedife

stuart45 said:

The problem is that you will get a lot of different opinions about CWI, so it's different to really know.

This is what makes me nervous. When I do a bit of digging on CWI, there are just more and more things to watch out for. I cannot let this happen as my house already has an issue with Radon and this will make it worse. Is there a way to tell if it goes all the way through?

This is a picture of the base of my house, I'm hoping that's not going to be an issue come driving rain.

stuart45

wiftedife said:

stuart45 said:

If you don't have any walls subject to heavy, driving rain

What defines heavy driving rain? It's all relative so it's tough to know if this will actually be a problem for me. What I think is on my side, is that the outer brick wall of my house is clad in a screed/cement and then painted over. I can't really see rain getting through a layer of pain, screed, brickwork, insulation, and then block work.

It is a bit exposed at the bottom, but this is below floor level so I'm hoping that shouldn't be a problem.

BRE have done a map of the UK showing the areas most likely to be affected, such as Cornwall and West Wales. It also depends on whether the property is sheltered. 
Having rendered walls should help protect them from the rain. A decent CWI company should check the suitability of the property first. 

Chickereeeee

I guess you have seen this site?

https://www.housingtriage.com/cavity-wall-insulation-suitable-homes/

Grenage

The previous owners had it done on our house and it was a complete nightmare.  Then again we had 120yr lime mortar with lots of gaps.  I imagine it wasn't an issue until the added a giant sponge to the cavity.

Had it in our previous 70s home with walls in decent shape and no problems.

stuart45

There are some new bui!d's that get it done. The developers think it's a cheaper method.

fenwick458

if you are going to fill the cavity, just make sure the render is in good condition and water can't get in and it should be ok

Eldi_Dos

With the doubts you have about the product I do not think you would have peace of mind if you got it installed,better to go down the draft proofing thermal curtains route and see how bills go.
Is the loft insulation up to scratch?