eco friendly vapor barrier/retarder

Daox · 09-23-08, 10:06 AM

What have you guys heard is a good eco friendly vapor barrier?

My situation isn't new construction, but I'm looking at reinsulating my attic and the upstairs bath doesn't really seem to have a vapor barrier above it! I was thinking of laying in plastic in the attic and stapling it against the joists. Other ideas?

truckncycle · 09-23-08, 03:36 PM

I believe that most vapor barriers are some sort of plastic or poly. I would look for a high reuse content.

You may not want to add a vapor barrier over the bathroom though since it is a damp environment and you may actually want the vapor to move. Our attic has no vapor barrier over or under the insulation but I also live in a fairly dry climate.

Daox · 09-23-08, 05:56 PM

Yeah, the problem is my humid and cold environment. The humid warm air seeps up into the insulation where it slowly cools and condense depositing the water. The bathroom does have a vent fan and its always used. I guess I'm just being cautious.

Otto · 12-21-08, 06:24 PM

Keep in mind that the vapor barrier is a barrier to movement of moisture. Duh.

So, if you encapsulate a source of moisture, such as the lumber framing of your moist bathroom or laundry room, that moisture will stay right there making the wood moist and delicious to termites, unless properly vented. Otherwise, the moisture will migrate until it condenses on cooler surfaces, such as on water pipes or the inside surfaces of outside walls. Best to put the vapor barrier as close to the source of moisture as possible, so the moisture cannot get to the wood, etc..

mrbreadpuddin · 09-19-09, 09:52 PM

It is more important to make your bathroom cieling airtight than to have a vapor barrier, use spray foam around the fan. If you object to using poly, painted drywall is vapor resistant.

09-23-08, 10:06 AM	#1
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	eco friendly vapor barrier/retarder What have you guys heard is a good eco friendly vapor barrier? My situation isn't new construction, but I'm looking at reinsulating my attic and the upstairs bath doesn't really seem to have a vapor barrier above it! I was thinking of laying in plastic in the attic and stapling it against the joists. Other ideas? __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

09-23-08, 05:56 PM	#3
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	Yeah, the problem is my humid and cold environment. The humid warm air seeps up into the insulation where it slowly cools and condense depositing the water. The bathroom does have a vent fan and its always used. I guess I'm just being cautious. __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

09-23-08, 03:36 PM	#2
truckncycle Helper EcoRenovator Join Date: Sep 2008 Location: Roseville, CA Posts: 81 Thanks: 0 Thanked 1 Time in 1 Post	I believe that most vapor barriers are some sort of plastic or poly. I would look for a high reuse content. You may not want to add a vapor barrier over the bathroom though since it is a damp environment and you may actually want the vapor to move. Our attic has no vapor barrier over or under the insulation but I also live in a fairly dry climate.

12-21-08, 06:24 PM	#4
Otto Lurking Renovator Join Date: Dec 2008 Posts: 12 Thanks: 0 Thanked 1 Time in 1 Post	Keep in mind that the vapor barrier is a barrier to movement of moisture. Duh. So, if you encapsulate a source of moisture, such as the lumber framing of your moist bathroom or laundry room, that moisture will stay right there making the wood moist and delicious to termites, unless properly vented. Otherwise, the moisture will migrate until it condenses on cooler surfaces, such as on water pipes or the inside surfaces of outside walls. Best to put the vapor barrier as close to the source of moisture as possible, so the moisture cannot get to the wood, etc..

09-19-09, 09:52 PM	#5
mrbreadpuddin Lurking Renovator Join Date: Sep 2009 Posts: 1 Thanks: 0 Thanked 0 Times in 0 Posts	It is more important to make your bathroom cieling airtight than to have a vapor barrier, use spray foam around the fan. If you object to using poly, painted drywall is vapor resistant.