Never actually watched a hot mop happen Contractors and bathroom specialists Why is hot mop not used across the US? It’s very prevalent in CA PSA - you should hot mop several feet outside your shower - seen enough water damage outside especially if you have a door and... you let it just drip and you have a baseboard and drywall that isn’t waterproofed right next to itshow more

There are a lot of liquid applied waterproofing alternatives that don’t involve hot tar

Lots of cold applied alternatives now like RedGuard, HydroBan, AquaDefense. This is an outdated approach, but still works fine.

Yeah this is useless. What are you thinking, tar paper and hot tar to studs? Showers are easy to build and it never involves waterproofing studs. Shower liner with mud pan or pre-fab pan with flange is the only question that should be discussed here.

Hey @grok explain hot mop to Stephen and how far back this waterproofing method has been used and how widespread it is

@stephentpaul @grok So it’s not widespread and only do it just because that’s how it’s been done. We used to use people as farm machinery too and moved on. Perhaps it’s time yall caught up with the times and quit this retarded practice.

@stephentpaul @grok Ok you can believe what you wanna believe. It’s still widely used today in CA

read your own post. hot mopping is still the default standard for "track home builders. This is not synonymous with quality, efficiency or innovation. I would also hope you would put the waterproofing on AFTER walls are installed so the barrier is complete. Shower water hits the walls as well as the floor.

Looks like a pain Why not just use Schluter or a comparable waterproofing system?

Because we have Schluter?

I have built hundreds of high end homes on the east coast. Never have I seen this, and to be honest I would never want to see it. It’s a terrible way to waterproof.

We use better stuff now, like redguard or equivalent. And I dont just do around the shower. I do the whole bathroom sub floor, up the drywall 6 inch all the way around and a good margin up the walls behind sinks, drains, toilets, and washing machines. Same in the kitchen under and behind the sink, dishwasher and refrigerator. I have made custom bathtubs with the stuff.

I just did a remodel that I had to remove the old hot mop. That crap was like 3” thick in all the corners. It took days to remove 😩

But were there stains or mold or water damage or was the waterproofing good it did its job

It definitely did it’s job

That’s pretty old school! This is the new best way

Properly installed kerdi system works as well or better and doesn't fill the house with VOC's that outgas for 30 years. Amazed that california of all places hasn't banned it. It's far worse than formaldehyde in insulation behind your drywall.

Because they have a failure rate. The union’s top using that. It cracks. Then leaks. The tar gets old and fails !

Weird because it’s still used in CA my 80 year old shower had zero stains on the original wood when it got demoed to be remodeled

Gonna hot mop my whole house ;-)

I've never, ever seen a house with a shower that's been hot mopped.

Old school but I think Schluter solved this challenge.

@CollinJHumphrey @TannerBuilds @GrulkeLamonte @follard @akolyadich do yall hot mop where you are and if you don’t why not? Which waterproofing is superior

No one does that anymore lol

You just watched it be done and it’s done all the time jn CA

Horseshit lol, been in construction 30 years and never have seen this lol.

@JulieChangRE I’m in the Los Angeles area and seeing hot mop trucks is not uncommon, and not just at home construction sites. My shower was hot mopped when the tile guy built it out.

@JulieChangRE They do use it for low income housing a lot .

It's a PITA and the equipment is pain for just a shower pan. Fire hazard mostly.

What Jeff said is what my experience with tile contractors is as well in San Diego. They still prefer hot mop Some reasons I’ve heard 1. It’s fast 2. It’s more idiot proof aka you don’t need someone super experienced with schluter or whatever other material is needed because the hot mop is done by hot mop subs which in CA are done by specific large subs that just hot mop 3. They don’t experience a high failure rate so it ain’t broke don’t change. Stick with tried and true

The rest of the nation

European shiting themselves laughing watching American builders. You guys are like 3rd world country. You dont even know what tilt windows are or how they work😂 you 2x4 cardbox house people. Every fart can bring it down

D.R. Horton never hot mop in California, reason multiple class action lawsuits, they moved to Texas.

Hey @grok tell us more about these lawsuits and what is the problem. Was it hot mop failure that resulted in leaks and mold or was it something else like environmental

No public records link D.R. Horton class actions to hot mop in California. Known suits (mainly Louisiana, South Carolina, Hawaii) allege water intrusion, mold, and defects from poor ventilation, roofing, or design unsuited to humidity—not hot mop failures. Hot mop is traditional CA shower waterproofing; improper install can leak, but modern membranes are alternatives. D.R. Horton has long been headquartered in Texas and still builds in CA.

This seems like an incredibly dumb way to build a waterproof seal considering other commercially available water proofing shower systems like red guard among many others

5” thick 5000 mix concrete was poured into the shower for the pan.

Omg my ocd in the beginning he missed around the drain and the corner…but luckily I continued watching 😅.. That’s so satisfying to watch.. Makes me want to do my own bathroom next .. 🤣

Dang you can make content out of everything these days. Never thought watching a hot mop would be satisfying.

Hahaha. I feel videos of how do things work - how is the sausage made is interesting to a lot of people. But look at some of these comments in denial this is a waterproofing method in CA.

Most of the houses built in the Sacramento area were hot mopped up until recently. I’ve demod dozens that were decades old. It works great and I prefer it over schluter and their competitors waterproof membranes. With that said it’s harder and harder to get a hot mop so I’m currently using schluter and their competitors like everyone else.

Because there are better systems!

why do you guys build bathrooms out of wood? Here every wood house has a brick and mortar bathroom so it doesn't get obliterated by the humidity.

Prevelant in CA? Sorry but never seen a guy ready to go in the Home Depot parking lot with a hot mop.

Sigh @grok explain bathroom hot mop subcontractors and how no this is not a Home Depot guy you pick up in the parking lot. It’s licensed. Hot mopping has been going on in CA for decades and the subs who do this are not one off guys

Hot mop is a decades-old California shower pan waterproofing method: layers of hot asphalt and felt paper applied with a special mop over a pre-sloped base. Specialized licensed subcontractors (CSLB-licensed, often under roofing or limited specialty classifications, bonded and insured) do this work. They bring kettles of 500°F asphalt and professional equipment—not random day laborers from a Home Depot parking lot. Established companies have performed it for generations, and many tile contractors still prefer it for durability.

@GuberMocker It’s older than that @grok. It’s been used for roofing and bathrooms before the 1950s

True, the core technique of layering hot asphalt with felt is far older. Built-up roofing systems using that method date to the late 1800s. California shower-pan applications adapted it and became widespread by the postwar building boom, though similar bituminous waterproofing appeared earlier in Europe and elsewhere.

Because there's better, more available, and easier to apply products...is why

@grok is "hot mop" shower base installation prevalent in CA because of unique building code history?

I used it for 49 years in the US, still superior to me!!

Oh we stopped building things to last a long time ago in the United States.

Just wait until you see how New York City does it!

This is just old school roofing without any concern for safety