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Vapor Barrier in Bathroom

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[#1] Posted: 02/27/2005 - 3:47:46 PM
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Brief bio. I'm a licensed PE and I'm going to start inspecting homes starting this summer. I still want to educate myself just a little further until I start (which is why I've been lurking here for a while and there's nothing worse than in incompetent PE).

I'm currently building a new house. See the attached picture. In the bathroom, all walls shown are exterior, and the wall on the left of the pic is north facing. The insulators installed faced insulation facing the exterior of the home. I told the builder what happened and to turn the insulation around so the facing will face the warm-in-winter side of the wall, as the IRC requires. Since then, he has done nothing and the drywall has been hung. I've told him several times he needs to take the sheetrock down, re-insulate the wall so the vapor barrier is on the interior, then re-hang the sheetrock. Still nothing. So, I called the city engineer, and he too thinks that it's strange that the insulation is backwards and that he would check with the builder to ask him. The city engineer got back to me the next day and he said the builder said his insulator said (follow that?) that was the trade standard to turn the insulation backwards in bathrooms. This makes absolutely no sense to me.

Here's what I know. IRC says the vapor barrier needs to be on the warm in winter side of the wall, and the insulation manufacturer (Owens Corning) says the same thing.

Has anyone heard of reversing the insulation facing in bathrooms? Am I missing something?



Download Attachment: No Vapor Barrier - Master Bath North Wall.jpg
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Vapor Barrier in Bathroom
[#2] Posted: 02/27/2005 - 4:21:10 PM
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Rusty,

I believe your'e in a heating climate. If so,

The insulation as installed is completely incorrect. ESPECIALLY IN A BATHROOM.
The gable insulation orientation is inconsistent with the walls.

The vapour barrier should run behind the tub down to the floor and sealed with acoustical sealant ON THE WARM WINTER SIDE.


Furthermore, the vanity drain needs a line CO and the 90's replaced with two 45's (one street, one hub). They got the hot on the correct side, assuming red is HOT.
The window is incorrectly installed.
Go to the window and remove the insulation around the jamb.
Have they?
Insulated the window the full 2X.
Shimmed the window adequately (glass blocks are heavy)
AND where is the weather barrier?

It's time to put on the steel toed boots, this will come back to haunt you later on.

ONE MORE THING, Where is the protective cover for the tub?
I better stop.



RC
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Vapor Barrier in Bathroom
[#3] Posted: 02/27/2005 - 6:26:30 PM
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Quote:Originally posted by Corners

. . . The city engineer got back to me the next day and he said the builder said his insulator said (follow that?) that was the trade standard to turn the insulation backwards in bathrooms. This makes absolutely no sense to me. . .


Rusty,

Interesting. A high school dropout insulation subcontractor is bullying two engineers with, probably, a dozen years of higher education between them. I guess that street smarts count for something.

From where I sit, you don't need any educating about insulation or vapor barriers (maybe some education in the ways of dealing with the trades wouldn't hurt though). Your take is right. Listen to RobC he's nailed it.

Go fetch the documents that say it should be done your way (building code, insulation manufacturer's specs, Sunset's How to Insulate Mine House, etc.) and present them to the builder. Tell him that if the doofus insulation sub has any printed reference material that says it should be done his way that he'd better cough it up pdq. If not, tell the builder that he's got till the count of ten to start ripping out drywall or you'll call your lawyer, Rex, who'll tear the flesh from his bones.

After you've been inspecting for a few years, you'll develop a feel for the delicate ebb & flow of bullshit that comes out of the mouths of builders and, especially, subcontractors. With time, I'm certain that you'll cultivate your own stock of clever and witty rejoinders. In the meantime, I'll lend you a few.

Shouldn't you have a license for being that stupid?

Yeah, yeah. Keep on talking, someday you might say something intelligent.

I'd like to leave you with one thought. Unfortunately, I'm not sure you have anywhere to put it.

Just out of curiosity, are your parents siblings?

You! Off my planet!

- Jim Katen, Oregon

Jim Katen, Oregon
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Lenexa, Kansas
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[#4] Posted: 02/27/2005 - 6:46:08 PM
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Thanks for the reply.

Yeah, I agree with the insulation. It's not right. Good call on the insulation behind tub. I'll get that fixed when they fix the other walls. I keep telling the builder, but he's not doing much. I'm supposed to get back with the city engineer tomorrow, so hopefully he'll force him to make the fix ASAP (they've already hung the sheetrock and finished mudding, but I told him BEFORE any sheetrock is up. I guess he wanted to turn a 20 min job into a 3 day job.)

Not quite sure about the window comments. I guess I must tell you that it's not a glass block window. It's a vinyl pre-framed acrylic block window, which is much lighter than glass. It appears to be installed in the same manner as other vinyl windows. It meets IRC Section R613, IMO. But if you have other reasons for concern, please let me know.

I personally don’t have a problem with the two 90’s in this location. There is a cleanout located within 40 ft, meeting IRC P3005.2.4. Then, the only flow these two 90’s will see will come from the sink (this is the second floor nothing else is above it.). Are there any specific scenarios you’re worried about? Even if it were a code violation I’m overlooking, I’m not worried about this particular branch due to its location.

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[#5] Posted: 02/27/2005 - 8:39:20 PM
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Rusty,
As a general rule, 90's are not allowed in drain applications. They are ok in vent but not drain.
You could suggest two 45's and that would be much better (less chance of blockage) than 90's.
I would suggest any good plumber should know that.
As to the line clean out, it would be beneficial as a matter of convenience and good practice regardless of code.

Furthermore the vapour barrier should be CONTINIOUS, that means the stub wall has to be removed and a proper 6 mill vapour barrier rated material installed at that location.
I don't mean regular poly, it has to be rated as vapour barrier (without the U of course if your'e south of the border )

OOPS, my mistake, I thought the window was block. Regardless, you should check for shims and insulation the full thickness of the 2X.

How have they done the weather barrier around the window?

Rusty, I don't see a continuous barrier at the right partition. Have they not provided for that and at the ceilings too?


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[#6] Posted: 02/27/2005 - 9:02:48 PM
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How'd you get the pic in the post instead of a link?

Kurt in Chicago

"If I smell it, it goes in the report".............Phillip Smith...2012


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[#7] Posted: 02/28/2005 - 05:29:11 AM
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Quote:Originally posted by kurt


How'd you get the pic in the post instead of a link?


No problem. Just attach a picture in the regular fashion and submit the message. Then, go back and view your message. Click on the picture. You’ll get the URL for the picture. Copy the URL (right click or ctrl+c). Then, go back to the message and go into the edit mode. Use the insert image icon where you want the image to go. You should get the [ img] [ /img] in your message. Paste the URL between the [ img] and the [ /img]. It should look like [ img]http://www.XXXXXXXXXXXXXXX.jpg[ /img] Resubmit the message. Done

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[#8] Posted: 02/28/2005 - 05:39:32 AM
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One more thing, or is that possible?

I see the stub wall is resting on the floor instead of going through the floor and being supported underneath with blocking etc. The way the wall is framed doesn't look too stable from where I am.
Check out the wall for stiffness this aft.
I wouldn't buy the idea that the vanity will tie things together as there is no blocking in the wall to accommodate for that, unless it was added after the pic was taken...doubt that!

Let us know how you make out and send more photos.

AND while we are on the topic of blocking, how about towel bars, curtain rods.....

Now U know why it takes me forever to do an inspection.
Good luck this aft.

RC
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[#9] Posted: 02/28/2005 - 05:41:05 AM
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Quote:Originally posted by RobC


As a general rule, 90's are not allowed in drain applications. They are ok in vent but not drain.
You could suggest two 45's and that would be much better (less chance of blockage) than 90's.
I would suggest any good plumber should know that.
As to the line clean out, it would be beneficial as a matter of convenience and good practice regardless of code.



That's probably good practice in general, but I'm really not worried about this location. Just thinking generally, since this will be my personal home, I'll have an easy way to clean out these 90's if they ever were to get clogged by pulling the trap off at the bottom of the sink and putting a snake down there. That'd be easy. Also, just thinking about clogs, if anything going down the drain can pass the 90's in the trap, it's not going to get stuck in the other 90's. It's not like I'm going to have turds going past those 90's. It's only going to see water from the sink drain.

Thanks for the replys. I love discussing this stuff.

What exactly do you mean by a weather barrier?

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[#10] Posted: 02/28/2005 - 05:47:48 AM
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Also, before I forget

See if you can get some heat added behind the tub. As this installation is on an outside corner wall, north wall at that, you'll find your water will cool rapidly without some heat source under the tub.

And don't forget the insulation.....

RC
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[#11] Posted: 02/28/2005 - 05:59:44 AM
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I have a question: How do they plan to finish the front tub lip? From the pic, it looks as though there about 1" of 2x in front of the lip that is sitting right on the 2x. Seems to me that what ever is going to finish that tub lip, should go under it instead of butting into it.
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[#12] Posted: 02/28/2005 - 06:32:37 AM
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For some reason, the text doesn't "wrap" anymore. When I look @ a page, every sentence is in one line & I have to scroll to the right to read it. I know there's something to fix it, but I forget. Wha' happened?

After that, I suspect that this (the tub thing) is going to get interesting. If they can't get the vapor barrier right, does anyone expect them to put heat under the tub, frame the stubwall properly, set the lip of the tub, or get a cleanout in the drain line? Ain't happening w/out a fight.

As far as the cleanout, why? We don't have to have CO's in a vanity drain in Chicago; is it required elsewhere? Even if it was, why not just pull the compression fitting for the trap & go in that way?

Kurt in Chicago

"If I smell it, it goes in the report".............Phillip Smith...2012


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[#13] Posted: 02/28/2005 - 10:49:51 AM
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Quote:Originally posted by kurt

We don't have to have CO's in a vanity drain in Chicago; is it required elsewhere? Even if it was, why not just pull the compression fitting for the trap & go in that way?


Exactly why I'm not worried about the 90's.

I'm not quite sure how the tub is finished. I'll have to go look again and get back to you.

What's wrong with the stub wall?

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[#14] Posted: 02/28/2005 - 3:50:15 PM
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Ok. Now I need help, as I am confused.

Everyone saw the insulation installed in the first pic, right? Well, here's what it looks like with the drywall up.



They've installed "green board" over most (not all) of the backwards insulation. Now what? I called UGS about the green board, and it is NOT to be installed over a vapor barrier. They said if the insulation is faced, that the faced insulation needs to be cut to allow moisture to pass. If this is done, there really is no vapor barrier, other than painting with a low permeability paint (green board has a permeability of 30.2).

Question, if the backwards installed insulation facing is not cut, is that a double vapor barrier on that wall? If so, what is the correct installation in this application?

Please help.


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[#15] Posted: 02/28/2005 - 5:00:02 PM
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When we write the specs for new bathrooms, we require green board throughout the bathroom except that we specify Wonder Board or approved equal in wet areas.

For you experts out there, do you think that greenboard is adequate in tub and shower areas?

Steven C. Hockstein, AIA
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[#16] Posted: 02/28/2005 - 5:19:00 PM
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How about the insulation/vapor retarder in conjunction with the green board?
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[#17] Posted: 02/28/2005 - 5:48:18 PM
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NO

"They > THEY- Who's THEY

said if the insulation is faced, that the faced insulation needs to be cut to allow moisture to pass."

Most accurate statement - the VAPOUR will migrate toward the cold side, cause that's the way it is, and condense at the dew point in the wall.
As it condenses it will freeze further down the exterior envelope and thereby reduce the insulative qualities of the insulation and thereby move the dew point closer to the warm side and thereby the process continues until the dew point is inside the wall and thereby causing ice on your wall and thereby .............

You get the point.

So why is allowing vapour to travel into a cold wall a good thing?
I would recommend the assistance of a home inspector or building science professional to evaluate this installation and explain in detail the repercussion of all this.

It warms my heart to know the drywallers have taken the care to protect the fibreglass tub. AND I'm sure the 'mudders' will equally excercise the same due care and deligence in protecting it.

Would somebody pick up that 2 by with the nails in it.

The reason I'm now inspecting.

RC
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[#18] Posted: 02/28/2005 - 6:18:56 PM
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Still doesn't help me. I already know everything you're saying. What I'm wanting to know now is how a VAPOR retarder (in the states, we spell it VAPOR; check the IRC ) is (or isn't) supposed to be installed with green board. Right now, the builder/insulator is telling me that the correct installation is to install the insulating with the facing towards the exterior. I'm not buying this. I think this creates a double vapor barrier. Any thoughts?
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[#19] Posted: 02/28/2005 - 7:19:24 PM
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Quote:Originally posted by Corners

Still doesn't help me. I already know everything you're saying. What I'm wanting to know now is how a VAPOR retarder (in the states, we spell it VAPOR; check the IRC ) is (or isn't) supposed to be installed with green board. Right now, the builder/insulator is telling me that the correct installation is to install the insulating with the facing towards the exterior. I'm not buying this. I think this creates a double vapor barrier. Any thoughts?


Rusty,

This is from USG's spec sheet on green board (you can find it here http://www.usg.com/products/sh...prod.asp ):

Limitations: Not recommended for ceilings where framing is greater than 12 inches on center, or in remodeling unless applied directly to studs. Panels should not be installed over a vapor retarder or on a wall acting as a vapor retarder unless it will not be tiled or finished with an impervious paint. Panels are not intended for use in areas subject to constant moisture such as tub and shower enclosures, gang showers and commercial food processing; DUROCK Cement Boards are recommended for these uses.

It sounds like the person you talked to took part of a sentence out of context.

Here's what I think about your bathroom:

If it's a wall that will be wet or will be tiled over, you need cement board. (I like Hardibacker these days.)

If it's an exterior wall that's *required* to have a vapor barrier on the inner side, then you can use plain sheet rock (or green board *if* you don't tile it [which you shouldn't do anyway] or finish it with an impervious paint.)

There is no circumstance where it's a good idea, in your climate, to put the insulation up backwards. That's just plain dumb. The code doesn't allow it and USG doesn't recommend it. It's just the product of an ignorant insulation subcontractor's brain.

As for green board in general, my personal opinion is that it has no place whatsoever in modern home construction.

- Jim Katen, Oregon

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[#20] Posted: 02/28/2005 - 7:32:52 PM
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hausdok,

Yes, and I appreciate the link. I sent that to the builder. That paper said everything I knew and thought about vapor retarders. However, it does not address green board (water resistant gypsum), and/or tile installation. This is where I am a little lost.

Maybe I'm not being clear. Here's the 3 pieces of the puzzle I know:

1) Currently, the insulation is installed with the facing towards the exterior.
2) The IRC R318.1 and other documentation state that the vapor barrier needs to be installed on the warm in winter side of the wall.
3) The green board manufacturer, USG, states that a vapor barrier is NOT to be installed behind it. This is confirmed in IRC R702.4.2 and R702.4.3, which states, "Water-resistant gypsum board shall not be installed over a vapor retarder in a shower or tub compartment....Water-resistant gypsum backing board shall not be used in the following locations: 1. Over a vapor retarder in a shower or bathtub compartment. 2. Where there will be direct exposure to water, or in areas subject to continuous high humidity.

So I now ask, what is the correct insulation installation of a wall partially covered in greenboard, and partially covered in regular gypsum board?

I’m now inclined to say, there should be no vapor barrier behind the greenboard, and the current installation of the facing on the exterior side of the wall should be removed. Basically, tear down the drywall, rip out the backwards faced insulation, replace it with unfaced insulation, and use greenboard over all unfaced insulation with a good water resistant paint. What do you think?

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[#21] Posted: 02/28/2005 - 8:15:09 PM
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Good info, Jim. Thanks.

In this light, greenboard should be installed over a vapor barrier, and should not be used in a shower or tub applications when tiled. Cement board should be used in tile applications.

Now, how about the use of a vapor retarder with cement board?

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[#22] Posted: 02/28/2005 - 9:52:30 PM
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Quote:Originally posted by Corners

Good info, Jim. Thanks.

In this light, greenboard should be installed over a vapor barrier, and should not be used in a shower or tub applications when tiled. Cement board should be used in tile applications.

Now, how about the use of a vapor retarder with cement board?


Putting a vapor retarder behind cement board is fine.

If you don't already know about it, Home Energy is a great source of information on this kind of stuff. You might like this article: http://homeenergy.org/archive/...310.html

Now, go put a whoopin' on that builder.

- Jim Katen, Oregon

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[#23] Posted: 03/09/2005 - 10:24:02 PM
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Well, after almost 3 weeks, the builder is finally admitting defeat, especially since I got the city engineer involved. I "told" on them. The city engineer asked for documentation and any technical reason for the backwards installations, and while they said they had it, they could not produce any. So, I talked to the builder today and he said, "well, I guess we're going to tear out the drywall and do the patch work...". Almost as if he's doing me a favor.

Oh well. I won. Thanks everyone for your input.

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[#24] Posted: 03/10/2005 - 05:04:43 AM
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Quote:Originally posted by Steven Hockstein


For you experts out there, do you think that greenboard is adequate in tub and shower areas?



There is no good argument for greenboard anymore. None. At least, not in my world. I only use 5/8" Type X for everything, and Durock the bathroom wet walls.


That said, I will grudgingly admit that I've seen greenboard work fine for 15-20 year life cycles if the tile overlaying it is installed meticulously. The tile mastic is actually the savior; if it's laid in right, it creates a water impermeable layer under the tile. It fails when the caulk joints fail.

Oh, and congrats on winning; the builder was a dickhead. There's nothing worse than folks in charge insisting on being stupid.

Kurt in Chicago

"If I smell it, it goes in the report".............Phillip Smith...2012


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[#25] Posted: 03/11/2005 - 9:10:18 PM
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Quote:Originally posted by kurt

[quote]Originally posted by Steven Hockstein


Oh, and congrats on winning; the builder was a dickhead. There's nothing worse than folks in charge insisting on being stupid.


One more chapter in the drama, the builder is billing the insulator for the fix. I bet this insulator loves me. Everyone loves being told they're wrong.

I seriously wonder how many homes this insulator has done incorrectly in this area? I'm betting hundreds, and every other home in my neighborhood thus far.

   
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