Internal Insulation Costs

[Robertspaw]

Hi

I'm currently having my kitchen re-done in my Victorian terrace house. This has involved taking off the plasterboard from one of the walls (which has been studded-out) and has uncovered the fact that we don't have any wall insulation behind it. So we've now been given the option of putting insulation in the frame that already exists. Great I thought - but the cost the builders have come back with is £722 for 14sqm. That's just supply and fit of 75mm celotex to 14m2 of wall - re-boarding etc is additional.

Is it me or is this crazy expensive?

We're in Bristol.

Thanks

Pete

 

[pilsbury]

About £27/board, which works out at about £11 per sq m. If there was zero wastage that would be £154 material. Zero wastage isn't really possible, but draw your own conclusions for their labour and a bit of wastage.

 

[Robertspaw]

I would have thought it's a days labour tops?

 

[John D v2.0]

You could always have a go yourself! Dust mask is essential though.
Are they quoting for a vapour barrier too?

 

[Robertspaw]

Not sure about the vapour barrier- they haven't mentioned it. Is that necessary? Would love to do it myself but they need to board it before the weekend and I don't have any time before then.

 

[John D v2.0]

Well, when adding internal insulation you have to do a condensation risk analysis, especial in a humid room and especially with relatively thick insulation.
The inside of the original wall will be close to external temperatures, so it needs to be more vapour resistant towards the room side.

 

[Doggit]

At that price, they should be doing the whole job start to finish. I think they know they've got you by the short and curlies I'm afraid.

Ebay, about £35 per sheet for the Celotex. Assuming a 2.4m room height, then you'd need 5 boards, and about 30m of 3x2 timber set at 600mm centres, plus a vapour barrier. So, assuming £200 for materials, it's £533 for labour, and having to drill and fit the battens, then fit the celotex in between, and then staple the vapour barrier on, two men should be able to do it in half a day, and then fit the plasterboard in about half an hour. Really, it's days job for 2 men, including plastering, but that'll add about £70 for the plasterboard and a couple of bags of plaster.

So either tell them you expect the complete job done for that price, or get someone else to quote, and handle the delay.

 

[pilsbury]

Doggit, OP said they are using existing baton..... so even easier

 

[Doggit]

Sorry Pilsbury, my mind retains nothing nowadays. Roll on Dignitas.

But that makes it truly horrendous. I wonder if they managed to keep a straight face when they gave him the price.

 

[John D v2.0]

Perhaps they misquoted the job and are trying to claw back some money, this happened with us so we couldn't get any extras done in the end.