We have an Edwardian end of terrace (circa 1910) with cavity walls.

I have insulated the crap out of the loft. Next on the radar are the walls.

I’ve read some fairly mixed opinions about retro-fitted cavity wall insulation. Some internet ‘experts’ do a lot of nay-saying about it causing potential damp issues, or shifting/settling and only insulating downstairs etc.

One piece that really got my attention was likening the insulation salesmen to the ‘damp experts’ who come around with a moisture meter and only have one speech (you have damp, pay me money) – having experienced them in my old house I know that I don’t trust them one single bit.

On the other hand, my parents have had it done on every house they’ve owned and had no problems.

So, opinions/advice/experiences please… should I get it done?

Dave

Depends entirely on the property and, to a large extent, it’s position (ie if it is in an exposed position where wind and rain penetrates through the walls).

I decided against it even though every insulation ‘expert’ telling me it would be fine – just not prepared to take the risk.

That was the position I had reached m_f.

I suppose I need to find an actual expert to advise me. From what I hear, I’m unlikely to get anything other than a ‘yes’ from the ones who’ll survey for free. I’ll have pay for someone truly independant.

Dave

try and find other people locally with similar houses and see if they have had it done and what their experiences were?

you can often spot houses that have had it as there’s new pits of mortar between bricks in a regular pattern where they drilled.

fwiw – we have it on our 30’s semi and have never had any issues – actually to the point I got British Gas round to do a survey for their free installation thing – he was here about ten minutes – drilled a hole in the wall, put a camera in ‘you’ve already got it mate’. 😳

http://singletrackworld.com/forum/topic/cavity-wall-insulation-2

There you go.

oops, cheers Drac.

I didn’t bother searching as I didn’t think it would be a common question. Clearly I have underestimated the far reaching remit of STW.

Dave

silver bonded bead is the stuff to go for, costs more but less downsides

We used to have damp that cause mould to grow on the walls, after having cavity wall insulation fitted there has been no more mould, as well as the rooms being much warmer than they used to be. So a yay from me.

Bricks are porous, and teh cavity is there to drain water down the inside face of the brickwork. Thats why its important to make sure your weep vents above the dpc and above lintels are clear and let it out, or you can get damp problems. Many older houses won’t have these, which is why you sometimes get damp issues around the dpc or above windows.

Filling the cavity with insulation could theoretically form a pathway for moisture to the inner skin of brick/blockwork causing internal damp, however manufacturers say this doesn’t occur and in practice I believe is very rare – probably only if you have very porous bricks and are in a very exposed location.

I’ve got cavity fill, installed by a previous owner. I’ve also got concrete bricks which are denser than clay (so less porous). No problems here, but obviously can’t comment on how effective it is as no ‘before’ to compare to.

before going down the cavity wall insulation route its worth laying insulation between the floors.
I have done this in my house had in the 3 rooms thats it’s been done its made a huge difference in the groundfloor room and the bedroom above it. I’ve got one more room to do and part of the landing.
I bought the £3 insulation from b&q and its cheap and very effective.