Hot mopping is using hot asphalt to bed three layers of felt together to make a waterproof pan for your shower. The corners are reinforced with fiberglass bedded into the asphalt.

It's a west coast thang.

Hi
why wouldn't he just use a shower pan ?? Special size needed?? gary

thanks, mongo and gary. I talked to him today, he said that it is a west coast thing indeed and that he has done showers like this for the past 15 years. I am worried about applying asphalt in my home since I have a toddler. So, I asked about Kerdi and he does not know what it means :( I assumed that Kerdi would be commonly adopted these days. Guess I am wrong. I found one contractor who is 40 miles from me who says he has used Kerdi. My quest for Kerdi continues.

I'm on the west coast and got 6 contractor quotes for my bathroom remodel. All called for "hot mopping". I had no idea this was a "west coast thing" how interesting. How do they make showers on the east coast?

I've now done three (California) bathrooms. All have been hot-mopped (never thought to ask for anything else). The asphalt or whatever it is is completely covered up in the following steps, so I'm not sure why it would be a danger to children.

boymom, I was concerned about the fumes when the asphalt is being laid. And I am wondering if it would linger for a day or two? Also it seems strange that with Kerdi and other waterproofing techniques out there, the West Coast has still not changed.

Take a deep breath, relax, and let all your worries slide away.

Hot mopping is perfectly acceptable, and it'll pose zero risk to your family. You might have a bit of odor during and for a day or two after the installation. But the asphalt will be fully encapsulated when the shower is done. You'll never know it's there.

Away from the west coast the most common installation is to use a CPE or CPVC membrane.

I'm in CT, I've used CPE, Wedi, Kerdi, and topical trowel/roll on membranes. With the exception of trying Wedi a few years ago at their request, I've pretty much done nothing but Kerdi since around '95 or '96.

I offered a 10-year warranty on my houses and have never ever had a water-related callback.

Regardless of what you use for your membrane, you want the membrane to be on TOP of your preslope. You want the membrane to be sloped, not flat.

like mongo said, just make sure the slope is under the membrane.

Do not let them tell you it's ok for the membrane to be flat.