Hi
I am after some advice if that’s OK, as I am going round in circles here as I don’t have the knowledge - however I am really trying and it would be good for me to understand. I am the landlord of a property – small terrace built around 1900. The now ex-tenant never opened a window, dried washing inside the property and didn’t put the heating on, despite repeated requests from my letting agent. Consequently, my lovely house is now full of condensation. Had a RICS surveyor go out who confirmed this. The surveyor stated he saw no evidence of rising damp, but the floors would need to be taken up to confirm which I intend to do. In his report he states:
Internal repairs should include replacement of spoilt plaster coverings; consideration may be given to introducing insulated plasterboards to improve thermal performance of the walls and reduce the impact of low surface temperatures.
When re plastering, appropriate plaster coverings should be applied. If significant salt contamination remains in the masonry, typically trades prefer using a cavity membrane or salt inhibitor to protect new plaster finishes.
Recommended Actions:
• Remove spoilt and damaged dry-lined coverings – consider replacement with insulated plasterboard
• Replace salt contaminated plaster to lounge party wall
My letting agent had plasterer’s go in to quote for removing the wet plaster and/or heavily salted plaster and replace. That’s fine – were I am confused is regarding the internal insulation as I have read in houses of this age, that due to them being solid walls, internal wall insulation can cause more damp problems – and I could really do without introducing more damp! This is the email from my letting agent. Can anyone let me know if what is being suggested is adequate and would solve the problem?
Many thanks for any help!
I asked the plasterer about the effects of using insulated boards, or installing internal insulation and then plastering over, on the ability of the wall to breathe. The plaster did think this would be a problem, particularly as the gable wall is made of engineering brick – which has very small mortar gaps and is impermeable, so doesn’t breathe much anyway. He has suggested knocking off all the affected plaster and installing pressure treated timber battens directly to the brickwork, then screwing the new insulated boards to these before a plaster skim. This would give the benefit of some insulation and leave an air gap behind the boards to allow air to circulate.
On the party wall side, they are suggesting removal of all the affected plaster and then reboarding in the same way (with battens, but normal plasterboards) which should prevent them bridging the existing DPC. They did take out a piece of board from the wall where the kitchen door handle had already damaged it (the tenant had slammed it against the wall). The plaster board was very wet, but the brick wall behind was dry, suggesting its not rising damp but condensation). Upstairs, the only badly affected plasterwork appears to be in the alcoves either side of the chimney in the front bedroom. These areas would be treated in the same way as the gable wall in the kitchen.
The firm wouldn’t be offering any warranty on re-occurring damp issues (the only firms that would are the specialist damp companies) and they are a small two-man outfit (not VAT registered). However, we have used them before and had no complaints. They have quoted £1200 for the work downstairs and a further £600 for the bedroom upstairs, inclusive of all materials and waste disposal.
