Kitchen backsplash on exterior wall
erikdavitt
| Posted in Interior Design on
On walls that are made to dry to the interior (flash/batt walls and external rigid foam) I am curious if tile kitchen backsplashes on these walls create problems and don’t allow the wall to dry to the interior? If there is anyone who can point me in the right direction that would be great.
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Replies
Hi Erik.
This is not a question I have specifically asked, but I have seen many, many high-performance homes designed and built by very experienced folks with walls designed to dry inward and tile backsplashes on exterior wall, so I can't imagine this is a concern.
Conditions which result in failure when applied to an entire assembly often aren't an issue when isolated to a limited area. The area where the backsplash is installed might be relatively more impermeable compared to the stock wall assembly, but since it is limited to a small area of the wall the wall can still dry properly.
If you were applying redgard waterproofing (just to pick a product) floor to ceiling, corner to corner to establish a <0.5 perm layer behind a full wall of tile, perhaps that's a risk... but I'm guessing you're just talking about 2-3 feet of tile installed across the wall - there's still a lot of permeable wall left in that circumstance.
Even if you're installing over cement board instead of drywall, the rating of the cement board is well over 1 perm. I think the perm rating of the tile is the 'missing' data here, and I'm not sure I've ever seen perm ratings for tile. Hopefully someone will chime in if it's floating around.
It depends upon your local conditions.
In this video -- https://www.youtube.com/watch?v=rkfAcWpOYAA , starting about 27:30 -- Joe Lstiburek says that in a hot, humid climate you can't even mount a mirror on the wall, you have to put it on furring strips to allow air circulation behind it so that moisture can dissipate. He's talking about a place like Miami.
The scenario he's talking about is one where the inside temperature is lower than the outside dew point and it's hotter outside than in. The temperature gradient is driving moisture from outside to inside, and it's cool enough inside for vapor to condense. If you don't have an unobstructed drying path the wall will become saturated. In a more temperate climate it's not so much of a problem and you have seasonal variation in the moisture path that will tend to drive the moisture out.
Hi DC.
Thanks for sharing that. It's a good reminder that in deep cooling climates anything impermeable near the interior side of the wall can be problematic.