Questions & Answers

I’m a DIY homeowner and built a shower pan about three years ago. Recently, the tiles on the inside face of the curb started pushing outward, so I removed the inside and top curb tiles to investigate.

I couldn’t identify the exact point of water intrusion, but nearly the full length of the DensShield on the inside and top of the curb was wet, likely from wicking, and the screws used to fasten it were rusting. I have not yet removed the outside curb tiles or the pan liner to inspect the wood underneath. The wood does not feel soft, so I’m wondering whether the curb might be repairable without full removal.

I’m hoping to understand:

1. Why the curb failed — was the problem mainly my design, my technique, or both?

2. What the best repair approach would be now.

Build method, inside to outside:

• Stacked 2x4 wood curb

• Oatey vinyl pan liner wrapped continuously over the curb from the shower pan

• DensShield on top and both sides, coated with Aqua Defense and fastened with 4 screws per side/top, including through the liner

• Thinset, tile, and grout on top and sides

I may have used grout sealer, but I’m not certain. At the joint between the inner Denshield piece and shower floor tile, there was only a gap — no silicone or sealant.

I’m not sure where the water got in. My best guess is through grout joints on top of the curb, but I’m not confident.

At this point I’m trying to decide whether I should:

1. Remove and rebuild the curb entirely, possibly with brick or a prefab curb

2. Keep the curb structure and replace the DensShield with a better installation method (of course, patching the pan liner first)

3. Use a single solid threshold to eliminate grout joints on top

4. Take a different approach altogether? Thanks in advance for any ideas/suggestions.