We have internally insulated our house with the existing windows in place. Currently we have no insulation around the windows on the inside and as the wall is concrete the wall around the window sweats producing condensation and mould. Can anyone one suggest a solution to our problem please. Is there thinner insulation available that we can use around the windows on the inside.
Internal insulation
- Thread starter marymu
- Start date
Hi, unfortunately it isn't really possible to give a proper solution at this remove due to lack of information because there are many interacting factors at play here.
Walls don't sweat as such. When you internally insulated your external walls and left your window reveals untouched, you likely created a localised relative cooler surface (your reveals). The temperature of this cooler surface is likely low enough then that internal air borne water vapour is condensing regularly enough to allow condensation to form and mould to thrive.
Yes, you can likely get thinner insulation. However, covering the exposed reveal surface will likely just mask the problem and may well still allow mould to form behind the insulation - this is a real risk and my concern would be that there may also be a risk of this happening now behind the wall insulation already in place!
Every dwelling has the potential to have condensation and mould issues if the right conditions are allowed to exist & persist internally.
You may need to consider all of the following:
- Reduce the moisture load such as avoiding drying laundry indoors, repair any leaking pipes, gutters etc
- Keep the house warmer
- Provide adequate ventilation such that the internally generated moisture from normal domestic activities is exhausted efficiently before it gets a chance to cause issues
Walls don't sweat as such. When you internally insulated your external walls and left your window reveals untouched, you likely created a localised relative cooler surface (your reveals). The temperature of this cooler surface is likely low enough then that internal air borne water vapour is condensing regularly enough to allow condensation to form and mould to thrive.
Yes, you can likely get thinner insulation. However, covering the exposed reveal surface will likely just mask the problem and may well still allow mould to form behind the insulation - this is a real risk and my concern would be that there may also be a risk of this happening now behind the wall insulation already in place!
Every dwelling has the potential to have condensation and mould issues if the right conditions are allowed to exist & persist internally.
You may need to consider all of the following:
- Reduce the moisture load such as avoiding drying laundry indoors, repair any leaking pipes, gutters etc
- Keep the house warmer
- Provide adequate ventilation such that the internally generated moisture from normal domestic activities is exhausted efficiently before it gets a chance to cause issues
We used 25mm foil faced PIR for the window reveals. You can get it here.
mybuildingsupplies.ie
It is an easy job to put this in place around the window reveals. We then plastered directly onto the foil faced insulation (just be sure to score it 1st with a knife to give the plaster somewhere to stick and also use corner beading and scrim tape). Perfect results no condensation or mold.
However, as you already have mold in place, be sure to thoroughly clean the reveals 1st with parazone. You don't want any mold behind the wall.
If you only have mold on the reveals and nowhere else, then it is almost certainly just that, the reveals are significantly cooler than the rest of the house, so your getting condensation on the reveals, followed by mold. Insulating (after cleaning) will sort this problem. (i.e. no hot air touching cold surface, so no condensation, so no mold, not even behind the insulation).
If there is mold in other places too, then this is likely to be an overall humidity problem and will need a more holistic approach.
Unilin Floor Insulation Boards / Pitched Roof Insulation boards 2.88m2
Thin-R PIR Insulation Boards for Floors and Pitched Roofs (XT/UF) Key features: High performance floor insulation Can be used with new and existing floors Suitable for use with underfloor heating Also suitable for use in pitched roofs High moisture resistance 2.4 metres x 1.2 metres (8...
mybuildingsupplies.ie
It is an easy job to put this in place around the window reveals. We then plastered directly onto the foil faced insulation (just be sure to score it 1st with a knife to give the plaster somewhere to stick and also use corner beading and scrim tape). Perfect results no condensation or mold.
However, as you already have mold in place, be sure to thoroughly clean the reveals 1st with parazone. You don't want any mold behind the wall.
If you only have mold on the reveals and nowhere else, then it is almost certainly just that, the reveals are significantly cooler than the rest of the house, so your getting condensation on the reveals, followed by mold. Insulating (after cleaning) will sort this problem. (i.e. no hot air touching cold surface, so no condensation, so no mold, not even behind the insulation).
If there is mold in other places too, then this is likely to be an overall humidity problem and will need a more holistic approach.
Alternatively you can get 38mm insulated plasterboard, but it it thicker (due to the plasterboard) and you will still have to plaster it anyway.
store.sig.ie
Xtratherm PIR+PB 38mm (25+12.5mm)x2438x1200mm : SIG Ireland
SIG Ireland is a subsidiary of SIG plc, a leading European distributor of insulation & energy management, interiors, exteriors and specialist construction products.
store.sig.ie