I tried searching this site but could not find the answer, in my loft the rafters are fitted with space blankets and has been for a number of years but getting the decorations down I noticed the space blanket was cold to touch and in a ripped part I put my hand in and its wet but only inside the blanket not outside , I also done random checks in other parts and its the same. The space blanket is tightly fitted in between the raftes and does go right down to the eaves where I can get at it as alot of it is plastered over so I cant check. Is the condensation due to eaves being poorly ventilated or because this stuff is well compacted in, also no roof issues as a couple of years ago had a new roof fitted with breathable membrane ,
Loft condensation in space blankets
- Thread starter JOHNBOY42
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Have you got any ceiling holes, like down lighters puncturing the bathroom ceiling that would allow damp air from the bathroom in to the loft area?
Might you have fan vent ducting in the loft that isn't very well?
Do you have an unlagged tank water storage or boiler hw tank in loft?
Is there good air flow in loft? I assume vents were added in by the roofers..
Have you checked the hints bit at the top of the main section pages regarding condensation
Might you have fan vent ducting in the loft that isn't very well?
Do you have an unlagged tank water storage or boiler hw tank in loft?
Is there good air flow in loft? I assume vents were added in by the roofers..
Have you checked the hints bit at the top of the main section pages regarding condensation
//www.diynot.com/forums/viewtopic.php?t=160032
I think you have an extra problem because the plastic wrapper on space blanket will prevent water vapour from escaping.
I think you have an extra problem because the plastic wrapper on space blanket will prevent water vapour from escaping.
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OK, so it's wet on the inside face of the space blanket.
From what you describe it's not wet anywhere else, though this is not clear.
I wonder if condensation is just forming on the inside face of the foil, as it's colder than the rising warm air, and although perforated, not as breathable as it needs to be to stop this.
On the plasterboard under the space blanket, is it foil backed or does it have an intact vapour control layer, if not this may be compounding the issue.
From what you describe it's not wet anywhere else, though this is not clear.
I wonder if condensation is just forming on the inside face of the foil, as it's colder than the rising warm air, and although perforated, not as breathable as it needs to be to stop this.
On the plasterboard under the space blanket, is it foil backed or does it have an intact vapour control layer, if not this may be compounding the issue.
Guys, thanks for help/hints but just to be clear,there is no water tank in the loft..although there is no extractor in the bathroom the ceiling light where it may be possible to enter the loft is well sealed...just for clarification the loft was boarded out several years ago and already had the space blanket fitted into the rafters then about 3 years ago my son wanted to escape somewhere on his xbox so I put plasterboard up against the rafters and I can remember the space blanket was quite compressed against the roof membrane..now most evening he will be up there with his friends ...also the space blanket was right down into the eaves and well bedded....my own thoughts are there is no ventilation between the roof membrane and the plaster board but would this sweat on the outside of the space blanket also?.I am at a loss so any info would be grateful.
Oh.
Yes, you just don't have enough ventilation. The condensation is forming on the inside of the sheet as that is the coldest point, it may not present a major risk to the surrounding timbers but it will reduce the effectiveness of the insulation.
If any water penetrates the tiles, that's when you will have an issue as the lack of any ventilation will trap moisture in the rafters.
Yes, you just don't have enough ventilation. The condensation is forming on the inside of the sheet as that is the coldest point, it may not present a major risk to the surrounding timbers but it will reduce the effectiveness of the insulation.
If any water penetrates the tiles, that's when you will have an issue as the lack of any ventilation will trap moisture in the rafters.
Your new membrane will not work under those conditions effectively, take it down and put insulated plaster board over the rafters.
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