Adding Vapour Barrier to Existing

Old 08-14-03, 05:47 AM
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Adding Vapour Barrier to Existing

We are currently renovating our home.

It was built in 1959. It has a brick exterior, black drywall like ˝” exterior sheathing, 2x4 walls, fiberglass insulation, drywall like plaster board and plaster.

We have “gutted” most of the interior walls down to studs, removed the exterior brick, removed all the original ceiling insulation (that was fun!). However, we want to save the plaster ceiling and plaster cove that are in the living room.

My first question is how do I add a vapor barrier to the ceiling without taking down the plaster? Should I tape the vapor barrier between the ceiling joists or should I “loop” the vapor barrier over the attic side of the ceiling joist down to the top of the plaster ceiling then back up over the next ceiling joist?

My second question is how do I tie the vapor barrier from my first question to vapor barrier attached conventionally.

Old 08-14-03, 07:02 AM
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hi vr6rules, you have a unique oppertunity here. first of, there is a differance between moisture & vapor barrier, thou you didn't refere to moisture. vapor barrier would be installed over the wall sheeting(plywood, black saturated black board) that is attached to the studs. tyvec is the product of choice. a vapor barrier allows any moisture(humidy, small water penetration to evaporate. whereas a moisture barrier, like number 30 felt paper stops moisture, but will hold moisture behind the siding whichn is no good. i have never heard of putting a vapior in the attic, sorry cant help there.
Old 08-14-03, 11:16 AM
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You can go at it 2 ways. The insulation that you buy for this will have a paper on one side . Put the paper side down up in the attic on the ceiling. You could like just get this in say 6 " R 19 and when all done come back and blow more on top of it so you could get about a R 30. There also is a paint that you can put on that works like a V/B on the ceiling . In all of the outside walls in the 2"X4" be sure and put a R 13 with the Kraft faced paper to the room side. We put a 2 mil poly over this before we dry wall. ED

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