Hi all,
Sorry, long post incoming...
We're slowly getting on top of the damp issues in our 1920s bungalow. It is solid wall concrete block construction with roughcast render finish. It suffers from all the usual issues you might expect in a property of this type (and we live in Cornwall, so very high levels of humidity and rain!). .The walls are really cold to touch in winter months. Condensation is a major issue throughout the house, but we are working on this. Windows are double glazed, but old style with no trickle vents.
We believe that we may have an issue with interstitial condensation - all the external walls have been boarded out at some point in the past and as far as we can see there are loose sheets of polystyrene in the gap. There is no vapour barrier and large gaps under skirtings etc. Last winter we discovered that the inside of the external walls were dripping wet. This appears to be running down and pooling behind the skirtings and is causing the floorboards to rot.
Clearly this has been going on for years, but needs to be addressed. We replaced the roof and guttering last year and are in the process of repairing and painting the exterior, so this should rule out penetrating damp as a cause. Also confident that it is not an issue with rising damp.
We are thinking that we will need to rip out the existing plasterboard/insulation and then install new IWI, with a vapour barrier on the warm side of the insulation and sealing all gaps around skirtings, sockets etc. Is this the right approach? Or is there a better way that doesn't involve sealing everything off?
My main concern is the risk of trapping moisture between the walls again. The external walls have 100 yrs of paint on them - I assume this is NOT breathable. Is it risky to be effectively sealing both sides of the wall? Stripping the paint off the external walls is definitely not an option! I should add that EWI is also not an option, for various reasons - conservation area, cost, roof overhang is too small etc..
Added complication - we have a PIV system which does wonders for reducing condensation in winter months. I have read that these should not be used with a sealed IWI system due to the risk of damp air being forced out between the walls.. is this true? Is there a way around it?
Sorry for all the questions. Just trying to ensure that whatever remedial works we undertake are actually going to improve things, not make them worse! We are also working with a very tight budget so need to be mindful of the costs involved.
Any advice/thoughts greatly appreciated
Sorry, long post incoming...
We're slowly getting on top of the damp issues in our 1920s bungalow. It is solid wall concrete block construction with roughcast render finish. It suffers from all the usual issues you might expect in a property of this type (and we live in Cornwall, so very high levels of humidity and rain!). .The walls are really cold to touch in winter months. Condensation is a major issue throughout the house, but we are working on this. Windows are double glazed, but old style with no trickle vents.
We believe that we may have an issue with interstitial condensation - all the external walls have been boarded out at some point in the past and as far as we can see there are loose sheets of polystyrene in the gap. There is no vapour barrier and large gaps under skirtings etc. Last winter we discovered that the inside of the external walls were dripping wet. This appears to be running down and pooling behind the skirtings and is causing the floorboards to rot.
Clearly this has been going on for years, but needs to be addressed. We replaced the roof and guttering last year and are in the process of repairing and painting the exterior, so this should rule out penetrating damp as a cause. Also confident that it is not an issue with rising damp.
We are thinking that we will need to rip out the existing plasterboard/insulation and then install new IWI, with a vapour barrier on the warm side of the insulation and sealing all gaps around skirtings, sockets etc. Is this the right approach? Or is there a better way that doesn't involve sealing everything off?
My main concern is the risk of trapping moisture between the walls again. The external walls have 100 yrs of paint on them - I assume this is NOT breathable. Is it risky to be effectively sealing both sides of the wall? Stripping the paint off the external walls is definitely not an option! I should add that EWI is also not an option, for various reasons - conservation area, cost, roof overhang is too small etc..
Added complication - we have a PIV system which does wonders for reducing condensation in winter months. I have read that these should not be used with a sealed IWI system due to the risk of damp air being forced out between the walls.. is this true? Is there a way around it?
Sorry for all the questions. Just trying to ensure that whatever remedial works we undertake are actually going to improve things, not make them worse! We are also working with a very tight budget so need to be mindful of the costs involved.
Any advice/thoughts greatly appreciated