Insulating solid walls and creating a stud wall, cost per m2

[adamb4321]

I've got a small commercial unit that is around 10 yrs old that adjoins two older properties, my building shares two solid walls with these older properties.

These old solid walls are damp in various degrees.
I've been advised to cover with a waterproof membrane (Newton or similar) and then create a stud wall that is insulated with 75mm Kingspan, as i'm going to be hanging wall units on these wall its also been suggested that 25mm ply is used to overboard the whole lot before plasterboarding so I'll have something to screw into. The plasterboard will be to a tape finish.

Does all this sound reasonable and what would I expect to pay?

 

[noseall]

£80p/m.....?

 

[adamb4321]

I'm being quoted £140 p/m2, which seemed a bit pricey! I'd have a go myself but there's quite a lot if it 25m x3m and it would take me too long on my own.

 

[ban-all-sheds]

Get a few more quotes.

ATEOTD, if you don't want to DIY it then you will have to pay whatever people charge, no matter how expensive it seems here - the first company you asked are not going to come down from £140/m² to £80 just because you tell them that you got that price off an Internet forum....

 

[adamb4321]

Yes, good advice I'll get some more quotes.