Vapor Barrier under footing?

[kyles974]

I've searched but can't find.

If the slab is being poured the same time the footing is being poured, then wouldn't or shouldn't you put a vapor barrier under the footing as well?

I will be epoxy coating the slab, and my concerns are won't moisture get "pulled" in to the slab area if there is no vapor barrier under the footings and only under where the slab is?

 

[rockchucker]

Yes. Vapor Barrier under Footing also. At least I do.

 

[kyles974]

Yes. Vapor Barrier under Footing also. At least I do.

Thank you for you reply.

Don't want to be an ***, but;

I'm hoping someone can give me their experience if they have NOT or a reason WHY, instead of yes, I did.

 

[mypov]

Concrete is a porous substance and can wick water up from the ground. If you do not have the vapour barrier then chances are your floor will be moist, mould can grow - I have seen people not put the vapour barrier down as well as leave out the sill gaskets and in 2-10 years are required to replace their bottom sills and in some instances their walls because of mould, wrought, and moisture. my 2 cents.

 

[kyles974]

Concrete is a porous substance and can wick water up from the ground. If you do not have the vapour barrier then chances are your floor will be moist, mould can grow - I have seen people not put the vapour barrier down as well as leave out the sill gaskets and in 2-10 years are required to replace their bottom sills and in some instances their walls because of mould, wrought, and moisture. my 2 cents.

I'm not trying to beat a dead horse of vapor barrier or not



....just a vapor barrier about the footing area, please.

 

[pd59]

I've searched but can't find.

If the slab is being poured the same time the footing is being poured, then wouldn't or shouldn't you put a vapor barrier under the footing as well?

I will be epoxy coating the slab, and my concerns are won't moisture get "pulled" in to the slab area if there is no vapor barrier under the footings and only under where the slab is?

Thank you for you reply.

Don't want to be an ***, but;

I'm hoping someone can give me their experience if they have NOT or a reason WHY, instead of yes, I did.

You answered your own question in the OP. The part I bolded is why you would put a vapor barrier under the footing. Might as well do it seeing as vapor barrier is cheap anyway, especially if you plan on coating the slab.

 

[kyles974]

You answered your own question in the OP. The part I bolded is why you would put a vapor barrier under the footing. Might as well do it seeing as vapor barrier is cheap anyway, especially if you plan on coating the slab.

well, the "key" word I used was won't. This is because I do not know for sure.

So, if I'm posting this as a question, then maybe common sence "would say, um, must be he really does not know."


Regaurdless, I'm going to have the vapor barrier redone. Since, as we speak, it has been cut short of the footing, so I'm not going to chance it.

I would like to know for my "FYI".

 

[pd59]

well, the "key" word I used was won't. This is because I do not know for sure.

So, if I'm posting this as a question, then maybe common sence "would say, um, must be he really does not know."


Regaurdless, I'm going to have the vapor barrier redone. Since, as we speak, it has been cut short of the footing, so I'm not going to chance it.

I would like to know for my "FYI".

I wasn't trying to talk down to you, and i'm sorry if it came off that way. I was just trying to say the guess you made in your OP was a good one. I wish you good luck on your pour and your floor, and if you have any more questions, i'd be happy to answer them!

 

[ConCretin]

I've read the thread a couple times and gotta admit I'm not sure what exactly the kind of response you are looking for but I'll take a shot.

If you intend to apply an epoxy floor covering, you absolutely need a vapor barrier under the entire floor including perimeter footings. The thickness of the concrete is not relevant.

To take it a step further, I'd consider upgrading to a 35 mil product. Make sure all seams and penetrations are taped and protect it from damage during placement (put your reinforcing on supports).

Hopefully an answer is in there somewhere.

 

[K'ledgeBldr]

I've searched but can't find.

...wouldn't or shouldn't you put a vapor barrier under the footing as well?

The answer to your question is ...
Yes, and No.
According to the "wording" (and interpretation is a gray area) of the IRC (International Residential Code) vapor barrier is not required in the footing of a monolithic slab-
R506.2.3 Vapor retarder.
A 6-mil (0.006 inch; 152 µm) polyethylene or approved vapor retarder with joints lapped not less than 6 inches (152 mm) shall be placed between the concrete floor slab and the base course or the prepared sub-grade where no base course exists.

Exception: The vapor retarder may be omitted:
1. From garages, utility buildings and other unheated accessory structures.
2. For unheated storage rooms having an area of less than 70 square feet (6.5 m2) and carports.
3. From driveways, walks, patios and other flatwork not likely to be enclosed and heated at a later date.
4. Where approved by the building official, based on local site conditions.
The exception to the rule would be #4. As it would be an amendment to the IRC by the convening authority (local building dept). And then there are "best building practices".
I have a pdf diagram of mono-slab best practices- unfortunately it's too big to attach. Basically, the vapor barrier lays through the footing part of the mono-slab and is either laid over the form rail (and trimmed later) or cut and secured to the inside of the form rail. Once the formed are removed and the slab has had a 28 day cure- seal the vapor barrier to the mono-slab with a bituminous sealer just below finished grade so it can not be damaged by mechanical means.
As far as moisture being absorbed from the footing to the slab has more to do with soil type and weather conditions more than vapor barrier or no vapor barrier within the footing excavation.

 

[ConCretin]

According to the "wording" (and interpretation is a gray area) of the IRC (International Residential Code) vapor barrier is not required in the footing of a monolithic slab-

OP wasn't asking about minimum code requirements. He asked if his vapor barrier should extend under the perimeter footing. He is planning on applying an epoxy floor system amd needs vapor barrier under the entire slab.

 

[K'ledgeBldr]

He asked if his vapor barrier should extend under the perimeter footing.

Yes. And I answered the questions.

 

[BenWillems]

K'ledgeBldr, do you still have that PDF and is that something that you can post or e-mail it to me? I have an inspector with 30 years experience of building stick-framed homes and he is a little shaken up by my ICF house. I am using XPS and a vapor barrier under the footing and all of the slab.