Doing a bathroom remodel and need to replace shower pan, tile, etc. What is the greenest choice?

Asked by josh ziskind
Van Nuys, CA

What's the best method of water-sealing a shower area: shower pan, hot mopping, etc.?


Rick Goyette

Answered by Rick Goyette

Pawtucket, RI

Emerald Dream Builders

June 21, 2010

For each part of a renovation or new construction project, there exists a list of green priorities springing from the context of each part of the project.

The major categories (in my green mind) in no particular order are:

  • Energy Efficiency
  • Indoor Air Quality
  • Durability
  • Renewable Resources
  • Recycling/Recycled Content
  • Environmental Impact
  • Water (minimizing usage, managing runoff, storing and reusing rain)

For a painting project, Indoor Air Quality moves to the top of the priority list. Similarly, when constructing a building envelope for an addition or new home, Energy Efficiency and Durability top the list.

For a shower gut renovation, the one category that dominates all others is Durability. Without proper installation, there will be problems with moisture control and subsequent issues with water damage and mold. Even using the largest recycled-content tile, and the lowest-flowing shower head … if the shower does not hold up to the test of time and win the war of durability (moisture mitigation), the renovation is a failure and all-new resources will be needed to reconstruct the shower. Therefore, the greenest approach to this renovation would be to consider Durability paramount to the shade of green.

Choosing the correct materials and understanding the installation process for each is essential for this project. Let’s assume the demolition is complete and we are down to stud walls with the plumbing roughed in the walls.

Wallboard and Subfloor
One specification that I adhere to when building a wet shower area is to ensure that no paper-faced gypsum products or wood is used in the shower area. Paper-faced gypsum products include drywall, greenboard, blueboard, etc. The only acceptable wall covering for a shower area is cement board. Popular name-brand cement board products are Hardibacker, Durock, and Wonderboard. Many building supply stores carry generic versions that contain composite materials. Just be sure that those composite materials do not include wood fiber.

Install the cement board to the walls and floor of the shower area per manufacturer's instructions. For additional insurance, replace the ceiling area with cement board if your ceiling is exposed. Do not use joint compound and drywall tape to cover the seams. To maintain the integrity of the area, utilize fiberglass tape and fill the seams with thinset mortar.

Waterproof Membrane
I employ two “go-to” solutions for water-sealing the shower area. The first is a bit more expensive but extremely effective and easy to apply. Laticrete Hydroban is a rubber polymer membrane that is applied with a paintbrush. In two hours or less, you are ready for tile. Note that while this product can be installed over a wood subfloor, I do not recommend it.

This product is also GreenGuard certified, so you are not forced to compromise Indoor Air Quality to achieve superior Durability. While the waterproofing membrane installation seems easy, this is an advanced-level project. Despite the ease of installation of the waterproof membrane, you will be required to install a shower floor that pitches to the drain, which is not a weekend project for a typical DIYer. For more information and installation instructions, check this PDF from Laticrete

The second approach to waterproofing your shower area is a bit more DIY-friendly. The Schluter system is available at many home improvement stores and provides all the complex pieces to a shower renovation. The core of the Schluter system is a fabric membrane that can be installed over your cement board using thinset mortar. They also produce shower-floor templates that are pitched to the drain for easy installation. Just cut the template to size and install the fabric on the walls and floor and you are ready for tile. For a detailed installation guide and project checklist read this PDF from Schluter.

Tile and Beyond
Purchase tile and shower fixtures according to your own shade of green. However, remember it’s hard to brag about the durability of your shower system. A fancy green tile and low-flow showerhead will be the talking points when you are showing off your handiwork.

Lastly, don’t forget to ventilate your bath and shower area. Moisture is the enemy, and after you’ve completed this installation the best way to combat it is to ventilate the space.

Consistently, bathroom fans do not meet their own criteria for air flow. Do not skimp on your fan. I have seen fans that do not provide the cubic feet per minute (cfm) of flow as stated in their spec sheets. One fan that never lets me down when tested is the Broan QTRE 100S. This fan will sense that there is water vapor in the room and ventilate the room until it is gone. For the specifications on this fan read Broan's PDF here

Good luck on your project!


For more information:

Read architect Brad Hubbell's answer to "Are there nontoxic alternatives to vinyl and lead sheeting for shower pans?"

Also, check out GreenHomeGuide's green bathroom Know-How section for buyers guides and other advice.

Tagged In: durability

Do you have a question about greening your home? GreenHomeGuide invites you to Ask A Pro. Let our network of experienced green building professionals – architects, designers, contractors, electricians, energy experts, landscapers, tile & stone specialists, and more – help you find the right solution.