# do I need a vapor barrier and if so where?



## Just-Ice (Dec 3, 2009)

Im working in the basement of a split level home. I removed the old panaling from the walls to find some rotten 1by3's and dampness on the half of the one wall that is below grade. there was no existing insulation so the plan is to remove all lath strips and use 2" foam insulation board to insulate the walls then replace lath strips over that and sheetrock.
Do I need a vapor barrier and where would I install it?

There really wasnt much water and the owners are getting some gutter work done. 
What do ya got for me, Just-Ice.


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## TBFGhost (Oct 9, 2008)

Nice introduction....where is the water coming from...answer that question first.

And every basement that I have done I used faced ridgid insul, taped at the seams and then framed a wall 1 to 2" from that out of metal... But I always made sure any water issues where addressed first.


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## J F (Dec 3, 2005)

I'd put it in between where the vapor _is_ and where you _don't_ want it to be :whistling


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## john5mt (Jan 21, 2007)

you need one everywhere! you dont want water anywhere but in the pipes and plumbing fixtures:thumbsup:


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## The Coastal Craftsman (Jun 29, 2009)

Just paint every wall with 5 coats of epoxy :thumbsup:

I use these


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## Just-Ice (Dec 3, 2009)

hehe thanks for the tip.


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## WNYcarpenter (Mar 2, 2007)

does any one really know????

Everytime I've been on a basement finish project we do it differently.

1. 2x4 pt on walls with rigid foam, then 6mil, then DW
2. 4' blanket insulation, 2x4 spf(pt plate) walls with tyvek on the backside
3. 2x4 spf(pt plate) 2" airspace, batt insulation, 6 mil, then DW.
4. now ICF foundation with DW applied directly.

IMO, drainage is key...all the rest seems to hinge on how much square footage the HOer,designer, or architect is willing to give up.


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## katoman (Apr 26, 2009)

If you are using 2 " styro, no you don't need a VB. But the VB on the above grade wall above that needs to be sealed to the styro. 

Unless you are running the styro all the way up.


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## naptown CR (Feb 20, 2009)

Just-Ice said:


> Im working in the basement of a split level home. I removed the old panaling from the walls to find some rotten 1by3's and dampness on the half of the one wall that is below grade. there was no existing insulation so the plan is to remove all lath strips and use 2" foam insulation board to insulate the walls then replace lath strips over that and sheetrock.
> Do I need a vapor barrier and where would I install it?
> 
> There really wasnt much water and the owners are getting some gutter work done.
> What do ya got for me, Just-Ice.


Address the dampness issue first
When and only then can you continue the finishing process.
There are numerous ways to do this but without seeing what is causing the moisture we cannot tell you how to address it.


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## TBFGhost (Oct 9, 2008)

naptown CR said:


> Address the dampness issue first
> When and only then can you continue the finishing process.
> There are numerous ways to do this but without seeing what is causing the moisture we cannot tell you how to address it.


:thumbsup:


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## The Coastal Craftsman (Jun 29, 2009)

The way i see it done the most is paint the wall with the proper sealer paint(no idea what it's called), build wall frames from 2x4 and leave studs 1/2" from wall, Install insulation but leave an airgap for air circulation and disconnection from wall so that air can flow past all studs and insulation, 6 mil vapor barrior across the wall and all staples taped as well as corners then acoustic sealent to seal lower barrior to bottom plate. 

I dont know if this is a standard way but it's the way i seen it done the most. I have one to do in my own house soon so it would be interesting to know whats right and wrong.


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## katoman (Apr 26, 2009)

BCConstruction said:


> The way i see it done the most is paint the wall with the proper sealer paint(no idea what it's called), build wall frames from 2x4 and leave studs 1/2" from wall, Install insulation but leave an airgap for air circulation and disconnection from wall so that air can flow past all studs and insulation, 6 mil vapor barrior across the wall and all staples taped as well as corners then acoustic sealent to seal lower barrior to bottom plate.
> 
> I dont know if this is a standard way but it's the way i seen it done the most. I have one to do in my own house soon so it would be interesting to know whats right and wrong.


 
BC, check out " Building Science. Com "


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## TulsaRemodeler (Nov 24, 2009)

Holmes on homes :thumbsup:


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## Gus Dering (Oct 14, 2008)

I built a daylighted basement office building in the Seattle - Tacoma area. It had a retaining wall 12' tall X140' long and office space along the entire length. The front of the lower level was store front glass the entire length.

The walls were conventionally framed with a few inches of air space from the concrete wall. Fiberglass batts and drywall. T-bar grid ceiling.

Rained like hell all winter while we framed it. Nice and hot in June when we finishing it. Thats when I noticed water damage at the bottom of those furred out walls. Stress level at the max level possible. Thoughts of that wall leaking would mean disastrous consequences seeings how the side walk and parking on the upper level was in and.....

Turns out the moisture in the building was being vaporized by the solar gain of the store front, migrated to the back wall over the grid where there was no drywall, where it found that nice cool concrete and condenced. Literally running down the wall.

Ended up with a bunch of fans and dehumidifiers to dry the place out. Had to haul 5 gal buckets of water outside to dump them. In the neighborhood of 85 gals later we laid the carpet.

Make sure that does not happen to you. :whistling


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