Can You Put a Shower Niche on an Exterior Wall?

Can a Shower Niche Be Installed in an Exterior Wall?

As one of the leading bathroom designers here in St. Louis, I know how hard it can be to incorporate enough storage for a family’s needs into a shower stall. I also know how nerve-racking it can be to tamper with exterior walls and other structural components, such as when you need to install a shower niche.

Shower niches are a great solution both for storage and for design purposes. A shower niche, almost like a cooktop backsplash, creates a break in the wall tile that allows for unique tile patterns and mosaics. Can shower niches be built into an exterior wall, though?

Building Code Does Not Forbid Exterior Wall Shower Niches

International Residential Code (IRC) doesn’t explicitly address shower niches in exterior walls. This can be interpreted as a green light for exterior wall niches. However, there are important exterior wall building codes that must be adhered to that shower niches can impede upon, covered below.

• R-Value: Building codes mandate minimum R-values for exterior walls to ensure adequate thermal insulation. Installing a niche can reduce the wall’s R-value, potentially violating codes. The reduction in R-value comes from having to compress wall insulation (compressing insulation reduces its effectiveness, up to 25%), as well as potential removal of the insulation entirely.
  
  It is sometimes possible to fit the proper R-valued insulation behind the shower niche depending upon niche depth and stud thickness. This will depend upon your climate zone, as well as stud dimensions. Home construction featuring 2x6s, as opposed to 2x4s, typically allows ample room for shower niches.
  
• Structural Integrity: If your shower niche width requires the cutting of wall studs in order to be placed, you must do so carefully. Exterior walls are almost always load-bearing. This means that you must install a proper header in order to successfully transfer the load of the studs. You will have to consult with a structural engineer in such a case, who will provide you with the proper header specifications.
  
• Waterproof Construction: Shower niches are subject to the same scrutiny as the shower itself. The niche must be constructed using a waterproof membrane such as Schluter-KERDI-BOARD.

Do Exterior Wall Shower Niches Hurt Insulation?

An exterior wall shower niche will almost always not fit into the stud cavity without modification to the wall insulation. Typically, I am able to compress insulation batts (layered fiberglass insulation) enough to fit shower niches.

However, compressing insulation can hurt its R-value and thus cause you not to meet building code. For instance, compressing wall insulation that is of the R-20 quality causes an insulation loss of approximately 25%. You can view the study here.

So yes, if you have to compress or remove the insulation, your R-value will suffer as a consequence. However, in a home that features 2×6 construction and only requires R-15 wall insulation due to its climate zone, you will have plenty of room for a shower niche.

You can also opt to build out the exterior wall. By increasing the depth of the wall cavity, you are guaranteed space for a shower niche. The downside to this is that you lose valuable square footage.

Are Exterior Wall Shower Niches a Good Idea?

My professional opinion on exterior wall shower niches is that they are unwise and will likely result in the breaking of building code unless the exterior wall is furred out.

The alternative to a shower niche is corner shelving. Corner shelves are installed into the grout line, or behind the tile prior to tile installation using a L-shaped extension.

Corner shelves can be stacked, meaning you can place multiple shelves into one corner, separated by vertical spacing. A tiled corner shelf can be seen in the hallway bathroom done for a client of ours below.

It’s Getting Late, Let’s Conclude

Shower niches are a fantastic way to increase storage space and are also a great way to break up tile monotony. Unfortunately, exterior wall shower niches are likely to harm your home’s insulation. This problem can be overcome by building out the stud cavity depth.

Alternatively, you could opt for corner shelving over a shower niche. You could also have your plumber route your water supply lines in a way that allows for a shower niche on the same wall as the shower head.

I hope that this article has given you some insight, and I wish you the best of luck with your remodeling journey!