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Vapour Barrier in Shower - is by code in Ontario required?

  • Last Updated:
  • Nov 1st, 2021 4:52 pm
Member
Sep 12, 2013
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Mississauga

Vapour Barrier in Shower - is by code in Ontario required?

I got rid of the main contractor doing my Renos, now I’m looking at all the work pending and likely getting my hands dirty on some of them.

1. Is Vapour barrier in shower by building code in Ontario.
2. Fair to say that any contractor should install the Vapour barrier, I.e it should not be optional?
3. Does it matter that the shower location is not connected to exterior wall?

Ty.
11 replies
Sr. Member
Dec 21, 2020
946 posts
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Vapour barrier is required only on exterior walls and ceilings. If all the walls of the shower are facing the interior of the house then it's not required.
Member
Sep 12, 2013
326 posts
192 upvotes
Mississauga
RCLapCar wrote: Vapour barrier is required only on exterior walls and ceilings. If all the walls of the shower are facing the interior of the house then it's not required.
Ty. i could not find specific info on it, so your reply would be sense.
But if someone were doing reno, would it not make common sense to have it?
With Roxul safe& sound and vapour barrier - would you have roxul batts insulation without the vapour barrier?

Trying to figure out what is common sense v/s overspend.
Last edited by winjones on Nov 1st, 2021 1:30 pm, edited 1 time in total.
Deal Addict
Jan 21, 2011
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Roxul safe and sound is for interior walls and ceilings. You need Roxul Comfort Batt which has a rated R-value. Exterior wall is supposed to have 6 mil poly vapour barrier with smoke seal top and bottom sill.

Waterproofing for shower is another story, I wouldn’t cheap out there, but it’s your house.
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Feb 3, 2005
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exterior wall is insulated, then vapor barrier. you can put Roxul safe& sound in interior walls as a sound-proofing mechanism, but I'd guess 99+% of bathrooms do not do that step.

You are just dealing with basic "code" for exterior walls and it really isn't bathroom/shower reno specific.

For your shower reno, I would HIGHLY recommend you have waterproof membrane of some sort. A properly installed Kerdi system for instance... or... put up cement board/green board (mold resistant drywall)... and then roll on a waterproof membrane (such as RedGuard or Mapei AquaDefence) and caulk seams (an added level of insurance beyond the waterproof membrane in case there is slight movement and the membrane cracks at the seam).

You then tile right over top of the waterproof membrane and you are all set.

Just my opinion of course...
Member
Sep 12, 2013
326 posts
192 upvotes
Mississauga
lamin wrote: Roxul safe and sound is for interior walls and ceilings. You need Roxul Comfort Batt which has a rated R-value. Exterior wall is supposed to have 6 mil poly vapour barrier with smoke seal top and bottom sill.

Waterproofing for shower is another story, I wouldn’t cheap out there, but it’s your house.
Tiberius wrote: exterior wall is insulated, then vapor barrier. you can put Roxul safe& sound in interior walls as a sound-proofing mechanism, but I'd guess 99+% of bathrooms do not do that step.

You are just dealing with basic "code" for exterior walls and it really isn't bathroom/shower reno specific.

For your shower reno, I would HIGHLY recommend you have waterproof membrane of some sort. A properly installed Kerdi system for instance... or... put up cement board/green board (mold resistant drywall)... and then roll on a waterproof membrane (such as RedGuard or Mapei AquaDefence) and caulk seams (an added level of insurance beyond the waterproof membrane in case there is slight movement and the membrane cracks at the seam).

You then tile right over top of the waterproof membrane and you are all set.

Just my opinion of course...

Ty folks. yea it does make sense. With shower, i guess typically there is only 1 side, maybe 2m that are connected to a exterior wall. There will already the vapour barrier on the exterior side.

I will be doing the work myself and yes the Roxul Safe and sound is for sound dampening against interior facing walls. Then install vapour barrier on top.
Sr. Member
Dec 21, 2020
946 posts
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winjones wrote: Ty folks. yea it does make sense. With shower, i guess typically there is only 1 side, maybe 2m that are connected to a exterior wall. There will already the vapour barrier on the exterior side.

I will be doing the work myself and yes the Roxul Safe and sound is for sound dampening against interior facing walls. Then install vapour barrier on top.
YOU DO NOT NEED VAPOUR BARRIER ON INTERIOR WALLS!!! It's only required on exterior walls over the insulation. Adding it over interior walls does nothing other than waste money and material.

Now of course you want a waterproof barrier like Kerdi to keep water out of the walls, etc.

Vapour barrier IS NOT waterproofing (in case you are confusing the terms).
Member
Sep 12, 2013
326 posts
192 upvotes
Mississauga
RCLapCar wrote: YOU DO NOT NEED VAPOUR BARRIER ON INTERIOR WALLS!!! It's only required on exterior walls over the insulation. Adding it over interior walls does nothing other than waste money and material.

Now of course you want a waterproof barrier like Kerdi to keep water out of the walls, etc.

Vapour barrier IS NOT waterproofing (in case you are confusing the terms).
Ty - heard you loud and clear on the vapour barrier. Kerdi system is probably outside my pay-grade, i will leave that for the pros to do.
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Jun 27, 2015
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East York, ON
winjones wrote: I got rid of the main contractor doing my Renos,
Ty.
What is a main contractor ?
Why did you get rid of him ?
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Member
Sep 12, 2013
326 posts
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Mississauga
CuriousC wrote: What is a main contractor ?
Why did you get rid of him ?
See my other post on 4" hole in LVL beam without remedial plan.

RCLapCar wrote: YOU DO NOT NEED VAPOUR BARRIER ON INTERIOR WALLS!!! It's only required on exterior walls over the insulation. Adding it over interior walls does nothing other than waste money and material.

Now of course you want a waterproof barrier like Kerdi to keep water out of the walls, etc.

Vapour barrier IS NOT waterproofing (in case you are confusing the terms).
Is waterproof membrane (like Kerdi) required by Ontario Building Code for bathrooms/shower? Surely it is.
Deal Addict
Jun 27, 2015
2281 posts
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East York, ON
winjones wrote: See my other post on 4" hole in LVL beam without remedial plan.




Is waterproof membrane (like Kerdi) required by Ontario Building Code for bathrooms/shower? Surely it is.
Yeah I remember that one
So general is a contractor that does it all ?
My understanding was that it is the guy who coordinates all the contractors required for a larger job
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Member
Sep 12, 2013
326 posts
192 upvotes
Mississauga
CuriousC wrote: Yeah I remember that one
So general is a contractor that does it all ?
My understanding was that it is the guy who coordinates all the contractors required for a larger job
Yes exactly, he subcontracts to others. Now I’m reviewing the pending tasks - checking on everything and understanding what is code and what is nice to have.

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