I have a cinderblock basement in Texas built on a slab foundation. How do I insulate and waterproof a bathroom in this area as two of the walls of the bathroom will be on the cinderblock walls. This is new construction.
Cc russell

You need to first ad a vapor barrier like Visqueen 6 mils. Build a wall with 2x4 construction and a pressure threated floor plate and then raise the wall in place. The wall attaches to the floor and the joists above, not the cinder block. Insulate with R13 batts or whatever is common in your area.

sometimes it can be difficult to tip in place a nice close fitting petition or frame a basement exterior wall of 2 X 4's for an insulating and attachment wall in a basement. The problem occurs if it is lifted in place and becomes stuck because the length can increase slightly while the wall is out of plumb and the diagonal (longer measure) takes over.

you may want to consider laying out and attaching a horizontal bottom wall plate out of wolmanized wood as ballenger1 provides and then attach top 2 x 4" plate so wall will be plumb. Now that bottom and top plates are in place, measure carefully each stud carefully and separately so they fit tightly and then toe nail them in place. This way you are not forced to tip a wall in place that will not get caught out of plumb,


Good luck with the task at hand.

bs5

I did not include every detail, the wall is built laying on the floor should be about 1/4 to 1/2" short. When the wall is raise you shim between the top plate and the flor joists. They are likley all a bit different so shimming allow a tight fit at each attachmentment. You do not need to nail at every joist, the nails can be every other or every third joist. What are you planning for the floor of this new bath and how level is the concrete?

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Originally Posted by ballengerb1

I did not include every detail, the wall is built laying on the floor should be about 1/4 to 1/2" short. When the wall is raise you shim between the top plate and the flor joists. They are likley all a bit different so shimming allow a tight fit at each attachmentment. You do not need to nail at every joist, the nails can be every other or every third joist. What are you planning for the floor of this new bath and how level is the concrete?

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I plan on tileing the walls and floor of the bath. The floor is level.

It is drier in TX than IL so moisture may not be an issue. We usually test for moisture by taping down a 1' square of visqueen plastic for a day and then open to see if there is condensation. If you are putting in a shower you should use greenboard on the walls and Durock or Hardibacker board for the shower unless you go with the fiberglass enclosure deal. Speedball1 is our plumber and can help you with the rough in or finish of the plumbing if you want help.

You can use something like Dryloc paint, but don't forget to etch first to act as a moisture barrier. Vapor barriers are also good.

We have used Styrofoam inslation with very good results.

Make sure you use the green board drywall in the bathroom.

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Originally Posted by peachtree

I have a cinderblock basement in Texas built on a slab foundation. How do I insulate and waterproof a bathroom in this area as two of the walls of the bathroom will be on the cinderblock walls. This is new construction.
cc russell

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I would recommend using metal studs. They are cheaper than wood and are galvanized. You have to anchor them to the floor. As for the two walls that are going to be against the block walls I would drylock the two blockwalls before you build and put up a thick vapor barrier such as thick plastic toprevent any possible water or moisture getting to your insulation or drywall and it would be wise to use mildew resistant sheetrock it's a little more exspensive but worth it.