Condensation on roof membrane
Discussion
I’m having the upstairs plastered atm on the renovation i’m doing, and the plasterers are near to doing the extension dorma I have built, however I after cleaning up I noticed what looked like a leak between two plaster boards.
I removed the plasterboard and the kingspan above it and found the membrane was full of condensation, this was dripping onto the kingspan and through a joint and out onto the plasterboard.
This has only just happened and I’ve had the plasterboard up for a good year. Could it be all the water from the plaster and roughing out coming out and going into the roof space from the holes where the down lights are going?
We have had three upstairs rooms plastered and this is the last one, left.
I removed the plasterboard and the kingspan above it and found the membrane was full of condensation, this was dripping onto the kingspan and through a joint and out onto the plasterboard.
This has only just happened and I’ve had the plasterboard up for a good year. Could it be all the water from the plaster and roughing out coming out and going into the roof space from the holes where the down lights are going?
We have had three upstairs rooms plastered and this is the last one, left.
V8RX7 said:
Did they install a vapour barrier ?
Did they tape the celotex boards ?
Presumably you have an unvented warm roof - do you have a breathable membrane ?
Not quite sure what a vapour barrier is on roof?Did they tape the celotex boards ?
Presumably you have an unvented warm roof - do you have a breathable membrane ?
The kingspan is taped up but there was a bit missing at this section, there is a breathable membrane below the slates.
I assumed it was vented Through the eaves from one side of the house to the other
The plasterer even commented that all the boards were bone dry before he started, and he had to unibond the whole lot
I’m trying to pin point why it’s just occurred, I’ve done s few things that could trap the moisture in the house, like block up around the old front and back doors due to it being unheated atm, I also took a ton of soaking wet sand into the house for the plasterers to rough out with, could this cause a bit of it
I’m trying to pin point why it’s just occurred, I’ve done s few things that could trap the moisture in the house, like block up around the old front and back doors due to it being unheated atm, I also took a ton of soaking wet sand into the house for the plasterers to rough out with, could this cause a bit of it
All the water used in the plastering has got to go somewhere. This time of year is generally humid also.
If you get a dry windy day get the windows open. If not a de humidifier is the way to go.
If the insulation wasn't up there then there would be beads of water on the under felt/membrane after the plastering.
If you get a dry windy day get the windows open. If not a de humidifier is the way to go.
If the insulation wasn't up there then there would be beads of water on the under felt/membrane after the plastering.
You have to stop the water getting up to the felt - either by taping all the joints - or better by also installing polythene over the lot.
As you've seen breathable felt isn't that breathable - particularly in the winter
The downlights, the missing tape and / or poor fitting of boards is probably responsible for letting the water vapour through.
Highlighted by the excessive water in the house due to building works.
As you've seen breathable felt isn't that breathable - particularly in the winter
The downlights, the missing tape and / or poor fitting of boards is probably responsible for letting the water vapour through.
Highlighted by the excessive water in the house due to building works.
V8RX7 said:
Alucidnation said:
Uni-bond the bare plasterboard?
Wow.
I'd had a plasterer insist on this - if it's been dabbed on and up for a while he said it gets too dry and sucks to fast.Wow.
As he does a good job and it costs nothing to roller a bit of PVA on - why not ?
V8RX7 said:
Alucidnation said:
Uni-bond the bare plasterboard?
Wow.
I'd had a plasterer insist on this - if it's been dabbed on and up for a while he said it gets too dry and sucks to fast.Wow.
As he does a good job and it costs nothing to roller a bit of PVA on - why not ?
Mind you, most of the spreads i have had the pleasure of, normally have it like water anyway.
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