Welcome to the DoItYourself Forums!

To post questions, help other DIYers and reduce advertising (like the one on your left), join our DIY community. It's free!

Adding vapor barrier


chaeberle's Avatar
Member

Join Date: Mar 2007
Posts: 100
MD

03-30-07, 06:39 AM   #1  
Adding vapor barrier

Trying to ask this again here, more clearly this time.

Attic currently has 3-6" depth of loose fill insulation with no vapor barrier beneath it. My understanding is that this is a bad thing - that in addition to more insulation, we really should put in a vapor barrier.

Our plan is to shift the insulation out of each cavity, one cavity at a time, and install plastic in each cavity, then put the insulation back in. When that's all done, we'll blow in more insulation to get to R-38 minimum.

So the questions are:
1) Am I right that the vapor barrier is a good idea?

2) How should I secure the plastic? I'm thinking push it tight up against the joists and staple.

Please advise! Thanks!

 
Sponsored Links
resercon's Avatar
Member

Join Date: Nov 2001
Posts: 1,873
NJ

03-30-07, 06:48 AM   #2  
http://www.eere.energy.gov/consumer/your_home/insulation_airsealing/index.cfm/mytopic=11810

This site discusses Vapor Barriers and how they should be applied and what qualifies as a vapor barrier. If you read through it, you will find out that several layers of paint on your ceiling below your attic floor does qualify as a vapor barrier. So your intent to move the loose fill insulation and install a vapor barrier is not necessary. Even if you feel you do not have enough layers of paint on your ceiling to qualify as a vapor barrier, it is still a lot easier to paint your ceiling than to move the insulation and attempt to install a vapor barrier. Furthermore you would not get the amount of coverage as you would by painting your ceiling.

 
chaeberle's Avatar
Member

Join Date: Mar 2007
Posts: 100
MD

03-30-07, 06:50 AM   #3  
Posted By: resercon If you read through it, you will find out that several layers of paint on your ceiling below your attic floor does qualify as a vapor barrier. So your intent to move the loose fill insulation and install a vapor barrier is not necessary.
resercon you just saved us a LOT LOT LOT of work!!!

The house is 65 years old - there's probably 8 coats of paint on the ceiling.

 
formula's Avatar
Member

Join Date: Jan 2007
Posts: 389

03-30-07, 09:43 AM   #4  
When you do blow in the insulation, go with blown cellulose. It holds its R-value as temps go down (fiberglass doesn't) and it's better at settling and sealing leaks as well.

 
chaeberle's Avatar
Member

Join Date: Mar 2007
Posts: 100
MD

04-01-07, 05:04 AM   #5  
Posted By: formula When you do blow in the insulation, go with blown cellulose. It holds its R-value as temps go down (fiberglass doesn't) and it's better at settling and sealing leaks as well.
Thats the plan, thanks.

We spent just about all day yesterday preparing for adding the additional insulation. You wouldn't think there would be much to do, but we wanted to add some storage space in the attic for "occasional" items (decorations, seasonal stuff, etc.) so we sistered in 2x12 joists to the existing ceiling joists to make an approximately 200sq ft area. After we blow in the insulation, we'll put plywood on top of those joists for the extra storage.

Oh and I installed some new lights and a switch up there. 2 flourescent flood lights make a huge difference compared to the old single pull switch bulb that was only on one end of the attic.

Now...whats good for muscle aches and pains?

 
Search this Thread