Hot mop shower pan waterproofing in San Diego County
Hot tar and felt, mopped on in layers over a cement pre-slope, flood tested. About two hours per pan.
What a hot mop shower pan is
A shower pan is the waterproof floor under your shower tile. A hot mop pan is built with hot tar, mopped on with a fiberglass mop in layers, with felt between the layers. That is what the name means.
Most homeowners have never heard the term. Tile setters and general contractors know it well. There are several ways to waterproof a shower. In our experience, hot mop is the one that lasts the longest, and it is what we do.
How we build it
Pre-slope
We mix cement and lay a pre-slope so all of the water drains toward the drain.
Hot mop
With the pre-slope in, we mop hot asphalt across the pan: three layers of 15lb felt paper and four layers of asphalt, one between each layer of felt and one over the top.
Reinforced corners and seams
Yellow fiberglass mesh goes into the corners and seams so they hold up longer.
Flood test
Water goes in to prove the pan holds. Sometimes we run the test ourselves, and sometimes the contractor does it once the pan has dried.
A pan usually takes about two hours. We could go faster, but we take the time because we would rather do it right.
What has to be ready before we start
Pass this list to your contractor. If it is not in place, we cannot do the job properly.
- The drain is set and flushed.
- Blocking is installed around the walls, typically 2x10 or 2x12.
- The curb (also called the dam or threshold) is in place: a minimum of two 2x4s, and three is recommended.
- The shower floor is solid. If it moves or feels like it could give way underfoot, we cannot mop it. Hot mop is heavy.
- The correct shower drain is installed.
- Demolition is finished. We do not demo.
When you can walk on it, and when you can tile
A pan is normally dry enough to step on about two hours after we finish. That is also when the flood test can be done. Tile can usually follow within the next day.
Does hot mop smell?
Yes. Hot tar has a smell, and we tell you up front, before we start.
What we do not do
- Demolition. It is normally done before we are called.
- Tile work. We work with tile setters, and they set the tile over our pan.
- Showers that are not prepped to standard. If the shower is not built the way a hot mop pan needs, we cannot promise it will be fully waterproof. If you still want it done, we will do it, without a guarantee.
Our guarantee
We guarantee our own workmanship. The pan is water tested before it is covered — by us, or by the contractor once it has dried — and a pan that holds water is a pan that was built right. If it fails because of how we built it, we come back and fix it.
The guarantee covers our work, not what happens to it afterwards. Until the tile is on, the pan is open to everyone else on the job, and a nail through it or a ladder set down inside it is damage we did not do. That ends the guarantee on that pan. Repairs to somebody else’s pan, and showers that are not prepped to standard, are done without one.
Get a quote
Call or text. Send pictures, measurements and the address so we know the job is prepped the right way. Every job is different, so we quote each one.
The pan, in cross-section
What is under your tile
Every hot mop pan is built in the same order. This is what goes in, and what has to be ready before we start.
- 1
Blocking
Around the walls, typically 2x10 or 2x12. It has to be in before we start.
- 2
Curb
Also called the dam or threshold. A minimum of two 2x4s; three is recommended.
- 3
Drain
Set and flushed before we start. It has to be the correct shower drain.
- 4
Cement pre-slope
Laid so all of the water drains toward the drain.
- 5
Hot tar and felt
Hot tar mopped on in layers with a fiberglass mop, with perforated felt between the layers.
- 6
Fiberglass mesh
Yellow mesh in the corners and seams so they hold up longer.
- 7
Flood test
Water goes in to prove the pan holds. Then your tile setter sets the tile over it.
The proof
Fill the pan with water. If it has not leaked within 24 hours, it was done well.
We run the flood test ourselves, or your contractor does once the pan has dried.
Questions
How long until I can tile?
Usually within the next day. A pan is normally dry enough to step on about two hours after we finish, and that is when the flood test can be done.
How do I get a quote?
Call or text. Send pictures, measurements and the address so we know the job is prepped the right way. There is no charge for a quote.
Are you licensed?
Yes. CSLB License #1092967 · C-61/D-12. We carry general liability insurance and workers’ comp.
Will it pass inspection?
Yes. Our pans pass any city inspection in San Diego County. The things an inspector cares about are the ones we do on every job: a proper pre-slope, the membrane turned up the walls and over the curb, reinforced corners, and a flood test that holds water.
How many layers are in a hot mop shower pan?
Three layers of 15lb felt paper and four layers of hot asphalt, with yellow fiberglass mesh reinforcing every corner and seam. It all goes down over a cement pre-slope, and it turns up the walls and over the curb.
Do you do a pre-slope?
Yes. We lay a pre-slope with cement so all of the water drains toward the drain, before we start the hot mop.
Do you do round corners?
No. We do tight, straight corners, reinforced with yellow fiberglass mesh. A rounded corner is quicker to form and leaves the membrane stretched thin exactly where it works hardest, which is where pans fail first.
Does hot mop smell?
Yes. Hot tar has a smell, and we tell you up front, before we start.
Do you do demolition or tile?
No. Demolition is normally done before we are called, and we do no tile work. We work with tile setters, and they set the tile over our pan.
Do you guarantee your work?
Yes, on our own work. Every pan we build gets a water test — sometimes we run it, sometimes the contractor runs it once the pan has dried. If it holds water, the pan was built right. If something goes wrong because of how we built it, we come back and fix it.
What we cannot cover is damage done to the pan after we leave. Our work sits open until the tile goes on, and other trades work over it. A nail driven where one does not belong, or a ladder set down inside the waterproofing, damages the pan, and the guarantee on it ends there.
Two kinds of job carry no guarantee at all: repairs to a pan somebody else built, because we cannot see what is behind another contractor’s work, and a shower that is not prepped to the standard the pan needs. If you want that work done anyway, we will do it, without a guarantee.
Read more
What is a hot mop shower pan?
A hot mop shower pan is the waterproof floor under your shower tile, built from hot asphalt and felt in layers. Here is exactly how one is built, and why it lasts.
How long before you can tile over a shower pan?
Usually the next day. A pan is walkable about two hours after it is finished, which is when the flood test starts. Here is the real timeline, start to tile.
What does a shower pan cost?
Every shower is priced individually. Here is exactly what changes the number, what we need to quote you on the phone today, and why nobody should quote blind.
Why a shower pan needs a pre-slope
A pre-slope is the sloped cement bed under the waterproofing that makes water reach the drain. Skip it and water sits still under your tile. Here is why it matters.
Getting a shower pan past inspection
What an inspector looks at on a shower pan, what has to be ready before the mop goes down, and why our pans pass any city inspection in San Diego County.
Hot mop compared with sheet and liquid membranes
Kerdi, RedGard, Hydro Ban and plastic liners all waterproof a shower. Here is an honest comparison from a specialist who only builds one of them, and why.
All guides
Everything we get asked on the phone, written down.
Other services
Steam showers
We waterproof steam showers. Call or text with pictures, measurements and the address.
ADA and walk-in showers
We waterproof ADA, handicap-accessible and walk-in showers.
Leak repair
Send pictures and we will tell you honestly whether a patch is possible or the pan has to be redone.
Where we work
Call or text for a quote.
Send pictures, measurements and the address so we know the job is prepped the right way.