“Hi people!” from Down Under. I have had great enjoyment for sometime now in reading and learning from all of you. Having just bought a house recently of doubtful lineage,I would appreciate your collective views on this problem. Background: Timber sided,aluminium clad dwelling, 40 -50 yrs old, been cut in half and transported to current location.On rejoining,[ about 6 years ago ] a tile roof was put on,but no wrap,sisalation [we call it]..tar paper and foilfacing..or insulation of any sort.
Now,for the 64 dollar question!
Is it worth applying a plastic film,then the foilfaced paper to the underside of the rafters,holding them up with 0.5 x 1 inch battens,or is it…take the whole lot off,and redo it?
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What is the interior finish? None? You can put unfaced insulation in the rafters and a vapor retarder on the inside (underside of the rafter). You have to cover that w/ drywall ... at least in the states we do (for fire safety). You DO NOT put plastic up first ... always put it on the warm side of the insulation .... warm in winter. There may be an issue if you are in a REALLY humid climate (like the deep south up here). I envision everything fairly arrid down there.
"You DO NOT put plastic up first ... always put it on the warm side of the insulation .... warm in winter. There may be an issue if you are in a REALLY humid climate (like the deep south up here)."No it goes on the side against the most moisture drive. Which is not always warm in winter.But in most areas of the country there is signficant drive in both direction so that plastic is not recommended AT ALL..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
No argument here. In most areas of what country? US? I thought in the upper midwest that the vapor retarder was still required on the warm side in winter.
Go look at buildingscience.com they have the maps and recommendations as the exact locations..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Because of difference in terminology, materials, and climates I am not sure what you are asking about.
I don't know that much about tile roofs, but it is my understanding that they need a weather barrier (tar paper or equivalent) under it.
Putting plastic under them rafter would just catch water after it came through the roof.
In the US most roofs are what are called cold roofs (in the winter) because space is ventalated. Best by vents in the sofits and at the ridge, but sometimes by gabel end vents.
And the floor of the attic is insulated. Putting insulation over or under the joist would not do any good. But a radaint barrier (foil) on the bottom of the rafters will do some good in the hottes climate.
Other roofs are called Hot Roofs, where there is no ventalation on the bottom of the roof sheathign, and the underside of the roof is insulated and sealed so that moisture for the house can't get to the roof.
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.