Hello all,
My name is Mark Campbell, and am in the process of having a house built in Nova Scotia Canada.
On the main floors, I have had the builder upgrade and add xps foam. Starting from the outside in, it will be vinyl siding, housewrap, xps, OSB, fibreglass. Now herein lies my dilema. Normally here, without the foam, a vapor barrier is added to the inside, before the drywall, however now with the xps, I imagine the wall can’t dry to the outside, right?
So my question is this: Should the inside vapor barrier be used in conjunction with the foam on the outside?
Any information would be greatly appreciated.
Best Regards,
Mark Campbell
Replies
Who designed the house, specified material selection and placement?
I'll eat your peaches, mam. I LOVE peaches!
For a heating climate, the foam should normally be on the interior of the assembly because of the problem you foresee.
If your heat cycle is less than six thousand degree days, you may do fine with the exterior foam and no inside VB. If may also depend on the type of heat source and whether you intend to use a humidifier in winter.
My guess is that you are borderline.
What I would probably do is use one of the vapour retarder products on the inside instead of a VB. That will slow progress of moisture from the interior into the wall assembly, but still allow it to escape so it does not build up and support mold growth.
Welcome to the
Taunton University of Knowledge FHB Campus at Breaktime.
where ...
Excellence is its own reward!
with 6,000 degrees of heat....
wouldn't ya need to worry more about than just insulation....
fire proofing comes to mind...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->
WOW!!! What a Ride!Forget the primal scream, just ROAR!!!
degree DAYS of heatingUp your way, it is probably closer to 12,000DD
Maybe you were just yoking, but somebody else probably wants to know...I forget what the baseline is, but suppose the comfort level base is established at 70°F. So if the ave. temp for the day is 60°, the DD reading is ten for that day. Then you add up all the readings for the year. One day averaging twnethy below zero means a ninety DD There are maps and sources to google to find out what your area is
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
I have a handle on it...
the OP might not....
right here the DD is 21,000... ceptic froze this year (still is) and it's 9' in the ground...
and it's 18,000 for a drop of 2,500'
base line avg is about 15/16,000.............
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->
WOW!!! What a Ride!Forget the primal scream, just ROAR!!!
Hello again,
Looked up my heating DD and it is about 3500.
Using ground source heat pump/forced air heat.
So if I use 1inch of outside XPS, then no interior Vapor Barrier?
Or one that can breathe. What are some products?
And the other question is if xps foam is used on the outside of the sheathing, is it nescesary to use tyvek on the outside of that?
Thanks for the help.
Edited 4/28/2008 4:03 pm ET by markus34
http://forums.taunton.com/n/mb/message.asp?webtag=tp-breaktime&msg=103001.1Here is another recent thread on the subject with other varied opinions, explanations, and links.I would have to ask my insulation guy the name of the vapor retarder he uses inside when he blows cells or BIBBs insulation.Not really necessary to use Tyvek with XPS if you tape the seams, but I probably would if as I suspect, you are near the coast with a lot of wind driven rain and moisture.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
thanks for getting all over this...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->
WOW!!! What a Ride!Forget the primal scream, just ROAR!!!
Could be membrain
frozen turds down 9' ????
haven't you guys heard of global warming ?
carpenter in transition
hadn't heard about that global warming thing much out here....
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->
WOW!!! What a Ride!Forget the primal scream, just ROAR!!!