Question about Vapor Barriers

[tioga0630]

On one of the HGTV shows--House Detective, probably--an inspector talked about the importance of a vapor barrier to keep an attic from becoming moldy.

The two roofing contractors I've had over to my mom's rancher have given estimates but haven't mentioned anything about installing a vapor barrier. Could this be because mom has loose globs of insulation all scattershot in the attic?

I asked one if, as long as he's going to basically tear the whole roof down to the rafters, he could vacuum up the loose insulation so that he (or I) could replace the globs with new rolled insulation. He didn't seem to want to do this, even though this home is in the Pocono Mountains and mom is constantly complaining about how cold the house is. (For a brick rancher only thirty years old, it IS darn cold.)

Do roofing contractors who are doing major roof improvements generally balk at getting involved in anything that doesn't concern the shingles, plywood, soffits, etc.? I'm posting because even though both guys who have come here are local and well-respected, this work is going to be the major home improvement of my widowed mom's life. She's a retiree on a fixed income, and I don't want some prima donna taking her money and then refusing to do necessary affiliated work she's willing to pay for!

[Michael Baugh]

I think you're looking in the wrong directions. If the rooms have at least 3 coats of latex semigloss or two coats of oil-based paint, the perm rating is better than .99, meaning that those rooms have a good vapor barrier already. If they're paneled, it's obviously a different story.

30 years ago, a lot of houses were being built with minimal insulation. Sounds like attic insulation is poor in hers. 30 year old windows may be leaking air. Considered good storm windows to supplement? And for the roof, it needs at least a foot of vent space for every 300 square ft of vented space, or the shingle warrany is void. Should be twice as much for comfort. For roofing questions, I suggest Owens-Corning at 1-800-ROOFING

[m Ransley]

Talk to an insulation contractor

[tbasc]

I would check recent work by the roofers. I am used to seeing a carpenter do the deck and trim with an insulator doing his part. At that point, I would think of a general contractor to coordinate the work. I know that sounds like a lot of folk, but one needs to consider cost v.value. TB

[Joseph Meehan]

More likely because there is a vapor barrier under that insulation.

It is not affiliated work. They do roofs, not insulation. It would be like asking your plumber to add a new light over the sink.

Don't remove the insulation that is there. If you want to improve the insulation, add more on top. This is something you may be able to do yourself. Or hire someone to do just that. Their time is likely to cost you less than the roofer, who is doing a dangerous job.

[bill a]

vapor barrier goes on the warm side of the structure, generally on the studs/joists before the drywall is installed. Putting it over the ceiling joists would trap moisture under the barrier and make the joists wet in the winter (bad idea). About the only way to add barrier on existing (interior) structure is to use paint made for that purpose. How much better barrier paint is over normal latex is the big question.

[tioga0630]

Thank you, I didn't know that. But I suppose no such procedure existed circa 1973?

[tioga0630]

Thank you, I didn't know that. But I suppose no such procedure existed circa 1973?

[m Ransley]

Oil paint is a good vapor barrier , in 73 it was likely latex, so repaint in flat oil. and add more insulation.

[bill a]

if your question is about using vapor barrier in general, circa '73, the practice was known and in use, but much building is done even now without proper vapor barrier to save a couple bucks.

bill