Poly being applied to Basement walls

[Brian A. MacNeish]

Originally Posted by dvalley

This is a huge difference between vapor retarder and vapor barrier.

I'm going to continue red flagging vapor retarders installed onto the interior studs of a basement.

Not a bad Idea but the rest of the world except you, myself and Joe Lstiburek's staff believe (like a religious belief) that you have to have a vapour barrier on the inside.

So you will be swmming upstream for years!! People will call the AHJ and they will tell them that, by code, a VB has to be installed on the warm side. Everyone from the barber to the minister will tell them (and you) that you have to have a VB on the inside. People will screw up their faces at you, look at you in total disbelief. In some people's minds, your reputation as a HI will drop for not knowing "How to do it right". That's the life of being a heretic!!

Been there, been doing that since 1977 (when I read the Canadian Building Digests). But stick to your guns, you'll be right!

[David P. Valley]

Originally Posted by Brian A. MacNeish

Not a bad Idea but the rest of the world except you, myself and Joe Lstiburek's staff believe (like a religious belief) that you have to have a vapour barrier on the inside.

So you will be swmming upstream for years!! People will call the AHJ and they will tell them that, by code, a VB has to be installed on the warm side. Everyone from the barber to the minister will tell them (and you) that you have to have a VB on the inside. People will screw up their faces at you, look at you in total disbelief. In some people's minds, your reputation as a HI will drop for not knowing "How to do it right". That's the life of being a heretic!!

Been there, been doing that since 1977 (when I read the Canadian Building Digests). But stick to your guns, you'll be right!

No one has ever challenged my recommendation, yet.

I've seen many vapor barriers installed on the warm side of a building (installed over the interior studs and insulation), so I always lift the plastic off of the studs to see what's going on underneath and guess what I find in several of these type of installations?

Mold.

Building materials must be able to breathe, and if contractors encapsulate the inside of a building with a vapor barrier, any humidity or condensation that does build up in the stud cavity doesn't have a chance of drying up and turns to Mold.

No part of any home should have a vapor barrier attached to it. The only area I do like to see a vapor barrier is on the dirt floor of a crawlspace.

[Carl A. Brown]

Here you go David.

http://www.youtube.com/watch?v=rhsHLvnQg60&NR=1

One day things will change in your favor!

[Carl A. Brown]

And then there is this one!

http://www.youtube.com/watch?v=D_Irt...eature=related

[Scott Widick]

Great Info - Thanx

[David P. Valley]

Originally Posted by cbrown1

Here you go David.

http://www.youtube.com/watch?v=rhsHLvnQg60&NR=1

One day things will change in your favor!

Yep. I'm simply going to red flag all those vapor barrier installs one home at a time.

I don't care what the other now-it-alls say about this foolish barrier, vapor barriers cause Mold build-up. I've seen it with my own eyes...

[Michael Larson]

bump

[Carl A. Brown]

David,

I just hate the fact that they blame alot of failures on stucco. House's are rotting from the inside out.

Let alone the failure of code enforcement by the citys and the rap the trades people are going to get. Then after coming to this BB the understanding the HI's EO insurance is going to be the scapegoat for the builders and city codes officials.

[Carl A. Brown]

I have been watching this thread
and this one!

http://www.iccsafe.org/cgi-bin/ultim...;f=26;t=000626

[john bubber]

I agree with David, see many bsmt walls w/poly against `em and often see
mold (not all). Have seen numerous HO`s who also 'thought' they had leaky basement but all they had was shttload of condensation dripping down wall(s) onto bsmt floor BEHIND paneling etc.

Originally Posted by dvalley

No one has ever challenged my recommendation, yet.

I've seen many vapor barriers installed on the warm side of a building (installed over the interior studs and insulation), so I always lift the plastic off of the studs to see what's going on underneath and guess what I find in several of these type of installations?

Mold.

Building materials must be able to breathe, and if contractors encapsulate the inside of a building with a vapor barrier, any humidity or condensation that does build up in the stud cavity doesn't have a chance of drying up and turns to Mold.

No part of any home should have a vapor barrier attached to it. The only area I do like to see a vapor barrier is on the dirt floor of a crawlspace.

[Brian A. MacNeish]

Originally Posted by john bubber

I agree with David, see many bsmt walls w/poly against `em and often see
mold (not all). Have seen numerous HO`s who also 'thought' they had leaky basement but all they had was shttload of condensation dripping down wall(s) onto bsmt floor BEHIND paneling etc.

The method with the poly against the wall can be used but it requires knowledge of the conditions that cause failure so that you can avoid them. Thousands and thousands of Canadian homes have used this technique without serious problems.

The BSC technique with the rigid foam insulation against the wall first is a bit more expensive but has an added safety factor if the needed air barrier function using the "airtight drywall approach" is not well executed.

[David P. Valley]

Ok...I would like to give you a sample of why not to utilize poly on interior studded walls.

I arrived at this particular inspection (4 year old home) and I see this bowing (pregnant) exterior wall....


I go into the basement and I see poly attached to the studded wall in question...


I pull the poly off the area in question and guess what I find?

Moist OSB with mold started to accumulate....


Above this area, the OSB was buckling excessively, but found that it was not a structural issue. It was the moisture build-up on the OSB that caused the buckling of the sheathing itself.

[David P. Valley]

I could not see where moisture was entering this area as the exterior vinyl siding was fine.

So I broke out my handy dandy IR camera, and there it was...right in front of my eyes.

You can see the moisture build-up on the sheathing and the insulation blanket itself....


Then I pull the insulation back a little further and viola....I detect excessive heat build-up from the water meter readers....



There were 3 water meter readers attached to the sheathing (on the exterior)wall, but the wiring was causing an excessive heat build-up in the cavities in this area, which in turn caused trhe OSB to get soaken wet.

So the moral of my beliefs are.... if the poly were not installed on these stud cavities, the heat build-up would have ventilated properly and this damage would have been avoided.

[Mark Allen]

On a side not, the IRC says you can not have exposed foam products in the home. Some of the basement systems that have insulation foam boards, then studs MUST be covered with drywall to be legal.

The homebuilder should do this and the Inspector SHOULD ensure this is to code. Alot of people build a home and are going to finish the basement later, no can do if you use foam boards on the inside. Too many builders are unaware of this. If you look at the "listing" of the particulare basement wall design, it will show 1/2" of drywall needed to be complete. Just a FYI!

Oh, I am an ICC guy, not a HI....just so you know.

[David P. Valley]

Originally Posted by Mark Allen

On a side not, the IRC says you can not have exposed foam products in the home. Some of the basement systems that have insulation foam boards, then studs MUST be covered with drywall to be legal.

The homebuilder should do this and the Inspector SHOULD ensure this is to code. Alot of people build a home and are going to finish the basement later, no can do if you use foam boards on the inside. Too many builders are unaware of this. If you look at the "listing" of the particulare basement wall design, it will show 1/2" of drywall needed to be complete. Just a FYI!

Oh, I am an ICC guy, not a HI....just so you know.

Foam boards are the best method in insulating the inside of a basement studded wall.

I recommend this to all of my clients who are interested in finishing their basement. You are correct...they must be conceled under drywall. Exposed foam insulation is a no-no.