Wall Vapor Barrier Question

jumbocactar

i've never made a wall w/4 or 6 mil vapor barrier on the inside(between stud and drywall) and living in the pacific northwest it was my understanding that it made the drywall mold... but i was watching this Canadian show holms on homes and he keeps saying that its crazy no one does this?? anyone got comments?

jumbocactar

ttt

Kgmz

It is one way to meet the code in the NW.

From the code:
The building design shall not create conditions of accelerated deterioration from moisture condensation. Above-grade frame walls, floors and ceilings not ventilated to allow moisture to escape shall be provided with an approved vapor retarder. The vapor retarder shall be installed on the warm-in-winter side of the thermal insulation.

These are 3 of the most common ways to meet the code:

1. unfaced batt insulation with 4 mil poly

2. faced batts

3. unfaced batts with a PVA primer on the drywall


Which one do you think works the best?

jumbocactar

well i guess ive always used faced bats, never had any call backs or mildew. the 4 mil seems more effective, but like i said when ive demo walls w/ it there was always mildew on the rock? maybe the moisture was from somewhere else. still ill have to think on it!

beachremodlr

Just replaced a shower valve in a bathroom where the plumbing was leaking. When I removed the granite wall sections. There was 4 mil plastic as a barrier. Luckily for the homeowner, the plastic also acted as a water barrier and were did not have to replace the studs nor the bottom plate, which was listed in my estimate. The plastic did not keep out every bit of water, but it did help prolong the life of the walls interior components.
Couln't hurt.

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kevjob

from the manufacturer of durock, vapor barrier must be installed agianst studs

green drywall no vapor barrier against studs

we use drywall and kerdi so no need for vb.

redgard on face of durock, no vb.

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Kevin
Basement Finishing Highlands Ranch Colorado
Littleton Colorado, Basement Remodeling
Kitchen Remodeling Denver