Vapour barrier for built-in closet?

October 6, 2009 9:00 AM

I have and Ikea Pax wardrobe along the wall of our bedroom and I'm going to frame in around it from the walls and ceiling to give it a "built in" look. The exterior wall behind it is poorly insulated (90 year-old house). It's got about 10" space all the way around and 4" behind. Should I be thinking about vapour barriers and such?

Sorry if this is kind of convoluted. I would like to leave the wardrobe freestanding with a 1/2" gap around it that would let me pull the unit out in case I need to access the electrical outlets behind it (plus I'm planning on eventually running a stainless steel chimney up through one of the wardrobe sections. So, I'm worried that leaving a gap will allow the air to get behind the wardrobe and cool off and condense. If I seal it off with plastic and some kind of weather stripping, do I need to pack the empty space with insulation? Something in the back of my mind is saying that I should just put some louvered vents to allow the air to circulate behind it.

Am I way over-thinking this?

posted by bonobothegreat to home & garden (7 comments total)

...just so you can picture it better, it's 3 Pax units ganged together to form a 10' wide closet along the wall.
posted by bonobothegreat at 9:02 AM on October 6

Good question, but I don't think that the temperature behind your PAX units would be different enough from the room itself to cause condensation on the inside face of the exterior wall. I mean, if you don't have water condensing inside your walls now, I don't think that it would happen because you've framed a niche. For piece of mind, I would leave the same 1/2" or more back there, and not press the the PAX against the wall.
posted by spoons at 9:13 AM on October 6

That 1/2" of air space around the unit and 4" behind it will allow plenty of ventilation to prevent condensation. Sure, it allows warm air to get behind the unit, but it also allows cold air to get out from behind it.
posted by ssg at 9:33 AM on October 6

If it were me I'd frame in the space for the wardrobe and properly insulate it, however local code would have you do so.

And speaking of you definitely need to check the codes on how the chimney should be run. Up through what amounts to a piece of furniture sounds like a bad idea, a waste of space in the wardrobe, a potential fire hazard, depending on the design, and a huge code violation.

Since there's 10" of space on either side, although less once you've insulated it, maybe you can plan now for the chimney, shifting the wardrobe over one way or another, and build the chimney space to code. I know I keep bringing up codes but, even if a hassle, they exist for a reason and can cause major expense down the line if you've failed to meet them, like when selling your house. Additionally, doing the work now for the chimney run is going to be much easier and at least a little cheaper when you're doing the construction than coming back at a later time.
posted by 6550 at 10:05 AM on October 6

Yeah, I know it sounds scary about the chimney.

I plan to use a double-walled chimney pipe that requires 2" clearance to combustibles and figure I'll have lots of room to spare. The plan is to frame the chimney in drywall and re-jig the one of the Pax units to fit around it so the whole wall still looks like an unbroken line of doors. I don't have space between the houses to run the chimney outside (and it seems from my research that it'll function better if it's run inside anyway).
posted by bonobothegreat at 10:42 AM on October 6

I don't know what state you live in but I'd check the building code on your flue pipe/chimney install. From my experience, most states will tell you that a sectional flue pipe should never pass through a closet or concealed space and should never be behind a drywall enclosure. I'd be willing to bet that what you're thinking of doing is a code violation where you live.
posted by birdwatcher at 4:48 AM on October 7

I thought about it and decided that an enclosed space with a 1/2" ventilation gap pretty much describes all the existing closets in our house, so I'm not going to use the vapour barrier for now. I'll double check the chimney code before going further. Thanks everyone.
posted by bonobothegreat at 11:48 AM on October 12