# help asap! Best insulation for a bath/exterior wall?



## 95025 (Nov 14, 2010)

Hey Bud - here's a link to a discussion that was had about this, some time ago.

http://www.diychatroom.com/f15/bathroom-vapor-barrier-19464/


If it were my project, I'd use un-faced insulation in the exterior walls, then install a good vapor barrier.


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## Just Bill (Dec 21, 2008)

Take a look at 'Roxul' insulation, a fairly new product. Insulates for heat/cold and noise. Insulate all 4 walls to keep it warm and quiet.


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## NJoytheRide (Nov 10, 2010)

Thanks for the quick replies guys. As I'm reading responses, I'm finding that my concerns are not just about the insulation,but also the vapor barrier.

I've read on some of the threads here that some people argue that a plastic vapor barrier over insulation will trap moisture between the exterior tar paper on the house, and this new layer, so that should not be done. That's why people say to use the Redgard.

Last night I found the NJ Residential construction code here:http://ecodes.biz/ecodes_support/free_resources/NewJersey/2009/09NJ_Residential/PDFs/Chapter%206_Wall%20Construction.pdf

and I'm interpreting it as I have options.

Here's what I was planning on doing, please tell me if I'm missing something:
1. (still need to pick an insulation)
2. apply Durock fiberboardon all walls, and also installing a "Ready Niche" above the bathtub.
3. cover all seams with fibritape and then mortar
4. apply Redgard to all durock surfaces
5. caulk the seams between durock and bathtub.
6. thinset, tile, and grout (all rolled into one)
7. Finally coat all tile with a Sealer

Also, please check out this video of the wall (you won't be rick-rolled, I promise):
http://youtu.be/VMWZl7L-B28


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## jklingel (Dec 21, 2008)

Be careful w/ a true vapor barrier; all walls should be able to breathe in at least one direction, preferably two. I do not see a VB in any of the drawings in Joe Lsitburek's book "Builder's Guide to Cold Climates" and I know they are being frowned upon on exterior walls, even in the coldest climates. Use cement board, w/ a liquid applied water proofing.


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## awdblazer (Dec 30, 2010)

i would be spray foaming with a closed cell foam


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