Cavity Wall Insulation

[jinnantonnixx]

We're booked to have this done in a couple of weeks, but I'm a little worried about possible complications, namely damp.

 

I've done my best to research this, and can find sites suggesting it's the best thing in the world, and of course the opposite.

 

My question is - have you had it done and have you had any problems?

 

As a bit of background, my house in a 1930s semi, with rendered brick and black mortar. We had some damp areas when we moved in, but these were remedied by a builder (who did some brickwork) and we haven't had any noticeable damp in the last few years.

 

TIA

[laserblazer]

We've had it done on every house we have lived in, including a 30s semi. Never had a damp problem and it significantly improves insulation and noise. I believe there were some issues in the early days that were linked to brick ties.

[chazzy2501]

if your house already has fitted insulation (after 1984) then they shouldn't touch the walls.

 

The air gap allows the wall breath allowing moisture to escape so stuffing it up isn't great. (why did the builder go to the effort of fitting air bricks if they were not needed) Also filling can be an issue, if it's not done perfectly the gaps in the wall will encourage condensation to form on the inside. (as it'll be colder than the rest of the wall)

[Pyroman]

We looked at having it done but after a company came round and didn't do a proper survey and then another company coming round claiming to be OFGEM and then turning out to actually be another company poaching the first company's business i thought better of having it done.

[Andrew_C]

Depends what filling you are having. The "blown wool" type isn't a problem with damp bridging, but the foam filling could be if cavities form.

[jinnantonnixx]

I think they stopped using foam a while ago (problems with it breaking down and the fumes, I think).

 

The house is 1930s.

 

I think the company will use a polystyrene bead of some sort.

 

The trouble with wall insulation is that it's a bu99er to get out if there's a problem

[pcstru]

I had it done on my previous house - a 1970's brick built thing. Didn't suffer any problems and it did improve the heat retention.

 

Which, suggests problems can occur but are rare. Cavity wall insulation: damp problems - Cavity wall insulation - Creating an energy saving home - Which? Energy . Everything I've read says it can't of itself cause a problem, but if you have other issues (cracked bricks, blown pointing/mortar), the lack of a cavity might exacerbate water penetration because of those. The solution would seem to be simple in those cases - fix the fundamental issue!

[jinnantonnixx]

OK, that's reassured me a bit. I know the rendering is in good order.

[Oaktech]

The blown wool or foam beads option I think is all they use these days as the expanding foam stuff eats the PVC insulation on cables that have been cavity dropped (which was standard practice for years)

 

I've had the blown wool thing done and it's been amazing - saved us on average £7 a month on energy bills on it's own and cut down draughts loads.