WestCon Tribune

October 2006

SEPTEMBER REVIEW

Shower and Bathtub Walls:
Sources of Leaks
Presented By: Mark Hunter, Hunter Plumbing

Our thanks to Westcon member Mark Hunter for an informative and lively evening discussing how water creates various problems in shower and bathtub walls. Armed with numerous slides and mock-ups, he presented evidence from cases worked and asked the audience to challenge and question his discoveries and remedial methods.

Plumbing makes a lot of messes in bathrooms. One problem area is water getting behind trim, tub spouts and trim plates . When water penetrates these areas, it has no way to get out. Plumbing codes require you calk all fixtures to the wall. Mr. Hunter recommends you do not calk 360 degrees around fixtures but leave a small gap at the bottom, thus allowing water some egress keeping it out of the walls. Testing by ASTM and other groups usually test the valves for leaks, but Mr. Hunter is not aware of any testing performed on trim.

Mr. Hunter used photographs to show how shower pans with zero clearance (where the lip continues on and the tile flange has no change in elevation) can create a situation where the water will get back behind the tile wall. The Tile Council Of America recommends at the juncture that there be silicone or a flexible sealant between the tile and the pan. This leaves no way for water to get out. Vertical notching tends to carry the water straight down to this joint allowing water to get into the wall and eventually leak onto the floor. When water stays in the walls, problems manifest.

Mr. Hunter showed samples of products from some manufacturers who now make shower pans with lips that have a change in elevation when it gets to the threshold and a weep channel built into it to allow the water to get out. Problems seen with these are the weep holes are grouted, calked or sealed in some way. The end result is the water traveling inside the wall and creating all types of problems. Manufacturers who make shower pans with weeps are requiring or recommending that a calk dam be installed. This is filling behind the tile with silicone or a water resistant substance that if the water travels in the direction of the weep and makes it above the threshold, it is unable to exit onto the floor or penetrate into the wall.
Many materials and different types of problems were discussed creating great interaction and questions from the attendees. Our thanks to Mr. Hunter for a lively and informative evening.

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