Cavity Insulation - Truth of moisture bridging the cavity?

suisidevw

Had a builder come around last week to quote for replacing the wall ties of our property. We had discussed various other bits and pieces and I mentioned CWI and he had nothing positive to say about it, mentioning the bridging of the cavity and damp travelling to the inside wall through the insulation etc.

A CWI salesman mentioned 'Mark' who they use, use a product which doesn't allow this to happen however I'm still sceptical.

Can someone tell me the truth? Will this happen? If so, I'll swerve!

BurningMad

I am also interested in knowing the effectiveness of this form of insulation along with potential risks of damp.

E-on are offering the service at a cost of £150. The company uses something called Instafibre White Wool and is apparently a new generation in cavity all insulation.

Any information on whether cavity wall insulation is worth it would be great.

suisidevw

Indeed. Marks is £99 for our semi detached 3 bedroom house..........

suisidevw

Thanks David, we plan to have our wall ties removed and replaced in the next month. IF we do decide to go ahead with CWI that will be after the wall ties are replaced. The right order it seems........ Thanks.

andrew-b

The thousands and thousands of us with CWI without problems can't be all wrong...

Ebe_Scrooge

If it's any help, my brother works for a CWI installation firm. They do private houses, but the bulk of their work comes from the local council - insulating schools, hospitals, council offices, etc. I would have thought that installing CWI must save money and not cause problems, otherwise the council wouldn't be able to justify spending the money on it - and I assume they have their own structural engineers who say it's OK. I don't know for certain, but that's my view for what it's worth :-)

Lube

It can happen. A friend of ours is a decorator and he said he often comes across properties that have damp due to cavity wall insulation

The reason there is a cavity is that damp cant not pass through air gap so if insulation is put in this fills the void

latecomer

As your friend is a decorator I'm sure he's fully qualified to say that its CWI thats causing damp. I'm sure he's seen loads of damp in houses which have CWI thats got nothing to do with the CWI itself.

moonrakerz

David_Aldred wrote: »

Hi,
I act as an expert witness for court work in matters of dampness and timber problems and can tell you for a fact that I have proved cavity wall insulation to be the cause of dampness within a considerable number of houses I have been asked to inspect.

I do not wish to sound harsh, but I could pronounce myself to be an expert witness "in matters of dampness and timber problems", and state that I have "proved cavity wall insulation to be the cause" of NO cases of dampness.

I am afraid you have picked a poor phrase; "expert" witnesses have in many recent Court cases have proved themselves to be far from expert.

The Sally Clark case; jailed for murdering her two sons on the "evidence" of an expert witness, who couldn't even master basic maths. Released after 3 years when the expert was totally discredited. She died 4 years later, in her 40s, her mental and physical health destroyed.

They are not experts in far too many cases - just self important people who can force their personal opinions onto others.

Your photos prove nothing whatsoever - the first one looks like a photograph of the planet Jupiter !
"A wet joist" - a duff DPC ? Leaking window frame ? a house in Workington ? oh no ! definitely CWI :rotfl:

Replace wall ties - that's a corker ! Good one for ex double glazing salesmen to have a go at !

phead

Interesting photos, but I guess the better question is how many houses do you inspect that don't have any damp problems?

I suspect on the balance of studies already carried out , and as we haven't really seen any significant problems from the millions of insulations already done that in general cwi is safe. The industry has grown a little too fast though, and there are more than a few cowboys around.

baldelectrician

I must concur with David (NOT as an expert witness).

From experience of older builders and tradesmen who are retired / semi retired the consensus is ' Wouldn't touch it with a bargepole - the cavity is installed for a reason.

There are better ways to insulate- insulate under (between) joists, internally (such as kingspan plasterboard on external walls when refurbishing)

I have it in my house- it was there before I moved in. If I had a choice I would not have it.