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I am thinking of finishing my basement and am wondering what is the proper order of things for framing the walls.

  • Do I put up perimeter walls first with electrical, insulation and vapor barrier, and then do the partition walls or
  • do I do all the framing (both perimeter and partition wall) and then insulate the perimeter?

I favour the second option as that will allow me to close off the utility room before moving on to do the rest of the basement, but not quite sure if that is the way it is done commonly.

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The only reason not to frame everything up would be logistics. If it would be hard to get the bathtub or drywall into the basement because of a framed wall in the way. Cost could be another factor. You would be staggering your project in a possibly inconvenient manner. It may also require extra sets of permits and inspections from the local gov't due to the fact that you'll be framing essentially twice.

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Typically everything is framed at once on a single floor. At the very least, anything load bearing is framed at one time before the next level is raised, but it's much easier to frame everything on the level and then run the joists for the floor above. There are parts that may be added during framing that would normally be done at other times, like insulation in corners (were the corner is covered by the framing, fire blocking between walls, essentially anything that you'll be unable to easily reach once the framing is complete. The biggest advantage of framing all the walls together is being able to overlap the second top plate for stronger joints, and less cross bracing needed throughout the structure.

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Don't put a wood frame directly against a basement wall that isn't insulated on the outside (i.e. with the insulation between the wall and the soil). A basement wall is a moisture sponge, and it will wick its moisture into the wood frame no matter how well sealed it may be on the interior, eventually rotting the frame and transforming it into a mold factory. And do not add a dedicated moisture barrier between the basement wall and the finished interior; especially not between the drywall and the frame. Moisture would condense there and start rotting the frame from the sill plates.

If you want to insulate your basement and finish the exterior walls, you have two options:

  1. Insulate with a vapor-impermeable material to keep the moisture in the wall itself. In this case, the fact that the material is a moisture barrier is okay because it clings to the surface so well, effectively sealing it up and not letting moisture collect between the wall and the insulation. For this, you would optimally want to use closed-cell spray foam to completely encapsulate the wall. You could also use cheaper XPS foam if your basement walls are flat. With a vapor-impermeable insulation like this, you could then frame and drywall over it. Make sure any framed walls you add are touching the insulation, not the basement walls themselves.

  2. Insulate with a material that is vapor-permeable but not moisture-sensitive, to allow moisture in the wall to migrate inwards and dry there. For this, you would probably want to use EPS foam. You would not want to add any moisture-sensitive materials to your finished wall, since the wall is expected to be moist. No wood frame and no paper-covered drywall. You could conceivably use cementboard right over the foam or mineral wool.

The following links might be very helpful:

http://www.greenbuildingadvisor.com/blogs/dept/musings/how-insulate-basement-wall http://www.buildingscience.com/documents/information-sheets/basement-insulation http://www.buildingscience.com/documents/bareports/ba-0309-renovating-your-basment http://www.buildingscience.com/documents/digests/bsd-103-understanding-basements/

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