Cold Outside Wall

sfrazi

I have had a few condensation issues in the past with my exterior bedroom wall which is cold all the time.

I have a cavity wall but no cavity wall insulation as the companies that do this stated my home was unsuitable as there are bits of rubble in the cavity.

I am in the process of redecorating and thought this would time to address this problem hence I have been thinking of dry lining it with some insulation.

Does anyone have any suggestions as to what would be most effective? Can I apply plasterboard straight onto the wall without hacking off the previous plaster as this doing that would be too messy? Would I use foil backed insulated plasterboard for this or is foil not acceptable as it would not allow the wall to breathe? Would it be better to apply battens onto the wall and plasterboard on top with insulation rolls in between?

Any suggestions are much appreciated.

Owain_Moneysaver

Battens and insulation then plasterboard. You would use foil plasterboard as you want to stop moisture from the room getting into the insulation and condensing, causing rot.

For 'seconds' of Kingspan look at https://www.secondsandco.co.uk

If you don't want to lose too much room size consider Marmox insulating board.

ic

You can also insulate on the outside of the house and then render - avoids reducing the size of rooms. Are you redecorating the whole house internally?

I'd like to insulate my bathroom when I renovate it, as its walls weren't suitable for cavity wall insulation. I found this page which links through to a PDF:
http://www.celotex.co.uk/applications/wall-insulation/solid-masonry-walls-internal

• Ensure that existing walls are permeable. Strip any gloss paint or vinyl wallpaper.
• Install a breather membrane where brickwork is only 103mm.
• Use the Celotex Insulation Saw to cut the 1200mm x 2400mm Celotex GA4000 boards to it the floor-to-ceiling height of the room.
• For optimum thermal performance, the unprinted foil surface should face the batten cavity.
• Fix horizontal battens over the insulation at the top and bottom of the wall to hold the boards in place.
• Seal all board joints to create a vapour control layer (VCL) using the Celotex Insulation Tape.
• Add further vertical battens over the insulation at appropriate spacing to provide adequate fixings for the selected lining system. Ensure that a batten coincides with each lining board joint.
• Apply an appropriate sealant around the perimeter of the insulation to provide a vapour seal.
• Additional battens are required around all openings to provide fixings for linings and grounds for skirtings etc. Battens should be minimum 50mm x 25mm treated softwood.
• The batten depth must be increased to take account of the conduit, if cabling is to be located within the cavity created by the battens.
• Use independent horizontal battens for heavy wallmounted components. Longer ixings may be necessary to it heavy items to the masonry, independently of the battens.
• Line window and door reveals with thinner Celotex TB4000 boards to reduce the risk of thermal bridging. Fix a batten around the edge of the opening and scribe the board to it the reveal. Cut the dry lining to suit and mechanically fix into the masonry reveal using proprietary fixings. Finish using an angle fillet at the frame and an angle bead or scrim tape at external corners.

It all makes sense to me, except the last part about scribing the board and using angle fillets and scrim tape. I just can't picture what they're describing. After some googling, I think they're saying line the window recess with a thinner insulation board, but then use triangular timber battens at the window edge to meet back to the actual window frame, as obviously the deeper wall would otherwise cover the frame and probably some of the glass.

Can anybody confirm I'm reading this right please?

Another question, what fixings would people suggest to use to fix the battens on top of the insulation? The depth is going to be say two inches of insulation + an inch of batten - but will also need to adequately secure through the plaster and into the wall behind.

sfrazi

I am thinking about using celotax ga4000 insulation boards basically...

50mm insulation boards(included is a vapour control barrier) on the wall held together by treated battens and then plasterboard on top.

Does anyone know if this is ok with my walls i.e. cavity walls and straight on to plaster?