Right, what’s the best option for this?

Along the side of our house is a single skin section comprising 3 v small rooms. Flakey paint on outer walls and something like latex screed (done roughlay) makes it pretty much a storage space at present. Want to make it more usable and presentable. Plus warm to use 10 months of the year.

Two plasterers have come round and said they would quickly rub down the walls then dot and dab 27mm standard board (with 12mm foam back) all round.

My concern is the boards won’t take unless walls are perfectly prepped, thus in 3 yrs we’ll start seeing issues.

Don’t want the cost of celotex nor the additional space it requires. Am happy to run thermal lining paper over the plastered outer walls and then add a single rad. Will also add another layer of latex and then some kind of flooring.

What would you recommend?

Cheers all

I’d go for proper insulation backed plasterboard. Maybe 50mm celotex, shouldn’t be that expensive or lose much space as you only need it on the external wall. Sounds like the wall won’t take adhesive that well so you could screw it directly to the wall. These’ll do it with a pilot hole screw tite pozi You’ll get a bit of thermal bridging at the screws but it’ll be way better than the nothing that you have currently. Pretty easy diy job to get it up then get the whole roomed skimmed or just easifil the corners and joins

for single skin, i always batten- 50mm kingspan in between, then 25mm poly backed boards over top (horizontally)remember vapour barrier.

You can probably find Celotex used/seconds on eBay.

APF

Cheers chaps. Only had 5 mins on here since yest hence delayed response.

I now have a couple more questions but will save those for tomo when I’m properly back online.

Hmm, didn’t think about screwing Celotex straight to the walls. Nickjb, are you saying the boards can be positioned next to each other all the way round. I thought they needed to be placed between battens/noggins?

leebaxter, the vapour barrier, eg Tyvek, goes between the Celotex and boards (not against the wall)?

So many versions of Celotex available, need to figure which is right. Ebay fine.

Cheers