Buying house with cavity wall insulation

[Chickenandegg8]

The house we’re currently buying has cavity wall insulation installed, done in 1996.
We have no idea what type of insulation was used or the current condition of it.

Do you think it would be unreasonable to ask the sellers if we could get a company in to use a borescope to view the condition of the insulation?
Conscious that it’s no longer under guarantee and could be costly to remove if it’s failing.

I cannot imagine a seller agreeing to this. Does the property have damp?

What does the examination entail? We're in an older property 1950s, and the neighbours had some retro-fitted...and then removed as it was causing damp. Is the property designed to have cavity wall insulation or was it fitted afterwards? There's lots of negative stuff out there so I'd be worried too if it was installed as an after thought.

We’re still waiting for the survey to see if they noticed any damp. House has been completely re plastered and painted in the last 3 years so nothing was noticeable.
I’m very wary of going ahead if there is damp recorded as it may be due to the insulation which will be costly to remove. I guess we’ll have to see.

They drill 2 tiny holes on each side of the walls and put a tiny little camera through. It was fitted retrospectively so will be beads/blown mineral wool or foam…

Didn't all houses built then have cavity wall insulation? My last house (built 1985) and this one (built 1990) had/have cavity wall insulation as did/do most of my local friends' houses. I've never heard of anyone having the slightest problem with it. I've also never heard of anyone wanting to check its condition.

What is it that makes you think it's a potential problem?

Edited to say that I'd missed that on your case it was retrofitted. Sorry

Can't see why they'd object then. How old is the house? Next doors insulation was polystyrene beads and it was removed by what seemed to be a big vacuum, from the loft, didn't take long. Not all property is suited for cavity wall insulation even if they have a cavity.

The problem is often not with the cavity wall insulation, but with insufficient ventilation. I’d be more concerned to see that there are trickle vents on all the windows for example. Show your survey will show up any damp issues, eg if the insulation is ‘bridging’ anywhere?

Early 70’s house.
No, this is what concerns us, especially if we have no idea on the condition, if it’s damp, degrading etc… I’ll see what the surveyor reports and take it from there I think.

Why would trickle vents be a problem? There a building regulationa requirement in most properties

I wouldnt buy a house with that. I would never have it done in our walls.

I didnt have trickle vents put in when we had our windows done a few years ago, I dont like the look of them. It was allowed for some reason that was explained to me, cant remember now why. We keep our windows open all year round.

I had it added in the 1980s extension to our old house and it caused absolutely zero problems. Damp would have shown within 3 years if it was going to be a major issue. I wouldn’t think twice about this insulation.

my mum has it. was pumped in through holes they drilled in the walls in the 80s. Forty years later no issues at all.

We live in a late 60s detached house with cavity walls. About 10-15 years ago every single one of the houses near where we live, all the same age and style, had cavity wall insulation done, and we did too. No issues with damp. Has reduced energy bills considerably. I would not allow you to drill holes in my walls.

Are you sure you are not getting confused with blown foam insulation which was all the rage for a while on the inside of loft/attic roofs and has caused serious issues? According to AI, there are 21.6 million UK homes with cavity walls, 71% of which have been insulated.

Exactly - that’s what I said. I’d want to check that there ARE trickle vents, to reduce the risk of condensation. Having lived in a house without them, they make a big difference to ventilation.

i think you're right that the op is gettimg confused with that inside the roof space foam stuff. which is totally different to the wall stuff, which is fine.

I'm not sure what looking in the cavity will tell you apart from what sort of insulation was used, you would be lucky to put a hole near a specific problem. I think the major problem is the insulation causing a water path along the wall ties or damp proof course so moisture can get to the inner walls. Is your mortgage provider happy? And can you get insurance to cover if it ever does cause problems? A little suspicious that they have replastered so that any obvious signs of damp have been removed, that would be a bit of a red flag for me.

No I’m not getting confused, retrofitted cavity wall insulation can cause damp and degrade the wall ties. Especially insulation that was installed 30 year ago. It can degrade, cause moisture bridging etc… that’s our concern

And as the OP said earlier in answer to this "House has been completely re plastered and painted in the last 3 years so nothing was noticeable."

So I don't blame them for wanting to know more about the cavity insulation as well as confirming that the property is suitable for such insulation. It might not be the horror story that has been reported but I'd want to know for sure.

https://www.bbc.co.uk/news/articles/c8606gp4711o

"30,000 homes fitted with botched insulation under government schemes, ministers admit."

Yes exactly, in the last 3 years. Any issues would have shown by then. If the house had been freshly plastered and painted immediately before going on the market I could maybe understand but nothing is going to pop up after multiple years. There is no need to worry about cavity insulation any more than any other update to the property having been botched.

The article is about external wall insulation which is not the same thing as cavity insulation - it’s for properties that don’t have a cavity.

How many homes are completely replastered and repainted, what might be a reason? There are 'red flags' here.
And as I said, our neighbours had their retro-fitted cavity wall insulation removed because it was making areas of their home damp and mouldy.
By all means say cavity wall insulation can be retro fitted and work well, but do not poo-poo any worries a house buyer might have about the problems it can cause.

Settlement, subsidence, thermal expansion, extensive electrical/plumbing/other work behind walls, damage from prior owners/their decorating choices, pressure from badly supported chimneys/roofs/windows etc, flooding, house fire, damp from other causes… there are loads of reasons for plastering that aren’t related to cavity walls. I’m currently having my new-to-me 1970s house fully plastered because of decades of (normal) settlement cracks combined with loads of chasing for new electrics and to get rid of dated artex ceilings, no sinister reason.

Lots of potential problems to look out for when buying property. Good to be clued up on what might cause a problem. In the case of cavity wall insulation it's good to know that not all properties are suited to it, and that types of cavity insulation can cause problems and also, like areas of your property, are even liable to failure over time.

I think you're right to be cautious. We have just moved out of a rental that had installed some time between 2010 and 2012, and I swear there was mould inside those walls - I'm allergic to black mould (exposure to which caused me to get M.E. many years ago) - I ended regularly spitting blood (could also have been poorly maintained drains - that came up black too) and on antihistamines to prevent it (there was 0 bedroom switch choices left). I also found a bunch of places in the walls with no insulation whatsoever with my temperature gun.

Anyway, I got the name of the company who installed it off the county's building control or building regs (you might not have any luck with this, given it was in '96), googled them. This company are so crap that they are mentioned in House of Commons White Papers, twice.

So, yeah. Persevere. At least insist on getting the name of the installation company as a starter for 10 if the owners refuse and see what you can find out about them.

Or, talk to neighbours. Others probably will have been sold it at the same time.

M.E. is really no fun and there is no cure. You're smart not risking damp/mould exposure and taking CWI seriously.