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tomaquar
Vapor barrier

Im replacing my vapor barrier. I went to buy some plastic and the sales person told me that the preferred method is now to staple the plastic to the floor joists overhead in the crawl space. I could describe it as a thin plastic ceiling forming a barrier between the air in the crawl space and the house. I like the sound of this (have allergies) but cant find any info supporting or contradicting. Any input? Thanks

dj1
Re: Vapor barrier

It may be extremely difficult to apply, secure and install if your crawl space is tight. Plus, it will restrict access to your plumbing, without cutting and tearing.

And if you suffer from allergies, don't even think of going in the crawl space.

Re: Vapor barrier

OMG! NO!
vapor barrier on floor! some parts of the country you also need to insulate at the floor.
placing the poly at the floor level will trap humidity in the joists, which will cool and condense right on the wood. You will most likely end up with major mold issues.
Worst advice I've heard all day!

HoustonRemodeler
Re: Vapor barrier

The vapor barrier in colder climates goes right under the drywall. In warmer climates the vapor barrier goes right under the exterior siding. In either case, the vapor barrier is part of the insulation envelope.

Where is your house?

JLMCDANIEL
Re: Vapor barrier
tomaquar wrote:

Im replacing my vapor barrier. I went to buy some plastic and the sales person told me that the preferred method is now to staple the plastic to the floor joists overhead in the crawl space. I could describe it as a thin plastic ceiling forming a barrier between the air in the crawl space and the house. I like the sound of this (have allergies) but cant find any info supporting or contradicting. Any input? Thanks

Was this advice obtained from Homedepot by any chance?
Jack

jkirk
Re: Vapor barrier

really though, eh jack ;) gotta love those "experts" in the orange smocks......

Timothy Miller
Re: Vapor barrier

Asume your currant plastic is on the dirt floor of the crawlspace. The best practices is to replace it with a 6 mill plastic and caulk to the foundation wall - but why remove the old lay new over it and avoid punctures from rocks in the soil below the old....
A great time to consider insulation of the floor 20% of heat loss is threw floors. A best practices is to install it and then house wrap- it allows moisture vapor transfer .

But never plastic to the floor joist as the joists need to be able to dry out as moisture levels change in the crawlspace. While your down there are the rim joists insulated great time to install 2" of foam caulked into place this is a huge improvement in keeping the home cozy

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