Insulating boards on walls

[pineapple]

Currently renovating an unlisted 18th century cottage with solid stone walls. No major damp issues apart from one 1st floor gable wall due to previous chimney ingress (we are taking off the plaster and letting the wall dry out).
Ultimately the builder has suggested lining all the external walls with insulating board to make the house warmer. He says there will be a gap and the walls will be able to breathe. He has an excellent reputation locally but I'm not sure. Are there any pitfalls?

 

[kazuya]

yea the rooms will be smaller

 

[noseall]

Apart from the obvious (above post) you will also have a fixing headache, in that you will need long screws in order to fix anything to the walls etc.

This could be particularly relevant in a kitchen area for example. I would be thinking about setting a ply covered stud frame in order to deal with the kitchen fixing thing as well as cradling the insulation.

 

[pineapple]

Thanks. It's an end terrace which also has a property butting on to the rear. So we are just talking gable end wall and front walls (kitchen and lounge). Plus the external walls of a built on shower room. How much space would I lose on the affected walls? He was saying it would make the property a lot warmer and I would see this reflected in the heating bills so worth the fitting cost.

 

[Jackrae]

Re the kitchen wall hanging problem

Rather than sheeting such walls in ply, I'd suggest 18mm moisture resistant MDF.
I've used it for years in such applications with great success
It's almost impossible to pull screws out of this stuff and the nice smooth finish it has is ideal for application of decorative finishes.

 

[SmileyDan]

You need a vapour barrier, especially if fibrous batts are used for the insulation. By insulating internally you are making the external wall colder, so if water vapour gets through the wall covering (it will) and then past the insulation (it will) it will condense on the external wall.

Do not use roll. Use rigid insulation and ensure all gaps are filled. It is essential all gaps are filled. I repeat: fill all gaps.

Easily digested overview: http://www.superhomes.org.uk/resources/insulation-vapour-barrier/

 

[jeds]

Currently renovating an unlisted 18th century cottage with solid stone walls. No major damp issues apart from one 1st floor gable wall due to previous chimney ingress (we are taking off the plaster and letting the wall dry out).
Ultimately the builder has suggested lining all the external walls with insulating board to make the house warmer. He says there will be a gap and the walls will be able to breathe. He has an excellent reputation locally but I'm not sure. Are there any pitfalls?

No problem if you use a phenolic thermal laminate board. Don't have a gap though - fix directly to the wall. Unventilated gaps behind rigid insulation are bad news.

 

[theprinceofdarkness]

Walk around your house and list every thing attached to the wall, window reveals , skirting boards, power points wall lights. . .
Its a shame that DPC/VCL sheeting will not cure the ends of the joists rotting.
Frank