Basement – Partially finished space, Framing/Vapor Barrier questions
Background: Newer construction, poured foundation with rubberized membrane and Dow blue foam on the exterior of foundation, perforated tile at footings on interior and exterior emptying into sump well. Experienced two years of seasonal changes – never any leaks, seepage, or signs of water (besides the tile network doing it’s job and emptying into the sump). The basement remains cool in summer, warm in winter – ductwork is installed above, but we keep the grates closed.
I’m planning on finishing our basement in stages.
Right now, I’d like to put up some walls to divide the mechanical area from the future finished space (mainly so my three sons don’t explore where they shouldn’t be exploring….). I also want to frame out space around our sump pump (make it look like a corner closet/pantry area.
The mechanical area – about 1/3 of the square footage – would remain unfinished storage. The future finished area would become one large rec room/home theater/bar area.
I have enough floor space that I can build most of the walls – excluding the egress window area where I’ll build window seats – far enough away from the foundation to access the space later (I’ve mapped out a 24” perimeter around all the exterior walls that’ll be finished with chalk to sketch the space). My thought is this – with enough space to maneuver between the foundation and backside of the finished studwall, I can install whatever types of wiring we need in the future, allow for air to circulate around and over the walls (suspended/drop ceiling), and monitor for any leaks down the road.
In the unfinished storage area, I’ll be running a dehumidifier to balance humidity regardless of my method of finishing.
Is it still necessary to use a vapor barrier between the foundation and the finished, drywall covered studs?
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This is how I finish now.
Foamboard against the foundation, glued and taped, floor to joist above.
A bit of space between wall.
Cover with drywall, might add fibreglass to stud cavities, might not.
This should keep warm air from condensing on cool foundation. Be wary of firestop at top of this wall.
Since there's a dropped ceiling, would worry about wiring later, all can be fished from above (with access made possible by the ceiling panels.
To lose 4' of space is usually not requested by a homeowner-space is a premium.
If you proceed with your idea, I'd lid the area behind the wall at the underside of your joists to create a firestop.
I like how Calvin described the wall construction. I can't see the 2' space being much of an advantage, nor the drop ceiling unless you like the look and feel of commercial space. If something needs to be upgraded down the road simply strip some sheetrock to get at what you need - it's cheap.
You will want a vapor barrier to keep moisture in the walls from entering the house, but the rigid foam will take care of that.
Good call....
I completely overlooked the fact that I can drop things in from above - sometimes the obvious is just that - and we overlook it.....
Thanks, Calvin.