Still More About Drains and Hot Mopping

What is hot mopping? Hot Mopping basically is the procedure of waterproofing the tiles, shower panels, and floors with multiple layers of hot asphalt and felt paper.

With all the blogs on drains you can tell that it presents more than a few issues and is one of the reasons that jobs need to be rescheduled…Here again are the basics that have to be followed with any standard drain application that is going to be Hot Mopped.

A two-piece bolted clamping ring type drain.

Note: The size and number of bolts is not a factor…remember an adjustable screw in screen top is not part of the clamping ring system

Drain Set

The drain must be lower than your curb height!

Note: This distance needs to be a minimum of 1-1/2″ to 2″ depending on shower pan size

drains hot nop

2″ pipe and drain must be used for a shower

Note: A tub to shower only is one of the most common re-modeling undertakings…tubs are almost always 1-1/2″…and this needs to be bumped up to 2″

Notice the in the picture that on a 3 bolt drain has 3 weeps, these are slot and holes that are at the bottom of the drain collar. You can see on the right side weep the installation bolts for this no-caulk Drain by Plumbing Product Inc. This is the drain that we supply and install when requested. This drain also fits the Ebbe Hot Mop Adaptor, which turns this regualar stack drain into an adjustable height stack. Ebbe offers a a stylist square top drain in a number of finishes to go with its adaptor or in can be used with a standard screen round type.

More questions answered next blog and some good news on a liner drain product!!!

All drains need to set flush and level with your sub-floor!

Note: If the drain can’t be lowered the floor must come up! An over pour of concrete, mortor, or plywood is often used!


Now that we have covered the basic hot mopped shower pan drain situations,we need to discuss the ADA and walk-in shower!!!

These shower pans have a no curb or a small 1/2″ high threshold at the transition between main floor and shower pan area, very popular, but takes far more planning from the start of your project…

The most important fact to remember is that you still need to follow all the rules for a regular drain application…except when you are using a custom built or prefabricated linear drain system, also called a trough drain, then the clamping ring style does not have to be used!!!

How can this be you say! Well the shower drain area becomes a deck area and a deck drain system can be used, and that means copper! Please check your local codes to see if your building department will approve this kind of connection for your shower pan. It varies for city to city but we have found that if brought to the attention of the building department and your inspector prior to install, you can get approval to maintain the effect you want in your shower.

Other linear drain system are available, especially those manufactured by Proline, which we also install, more on this system and its application’s later, for Hot Mopped Linear Drains and those special drain situations we will talk copper!

Flanges on copper need to a minimum of 8″ from inset or trough and any degree corner that continues up the walls…all seams need to soldered…

A sung fit is important at all corners…fur out as needed as not to damage soldered corner or cause cracking in your copper…caulks and fasten drain to floor and walls remember not to use galvanized or steel nails or screws to attach copper!!! a mix of metals causes pre-mature corrosion…the copper industry allows the use of stainless steel screws, very helpful when needed to secure to anchors onto a concrete slab.

copper trough drains 02

The use of copper decks drains is also being done, as designs for suspended teak floor patterns, four corner drain areas, Japanese cold water dip tubs are a few of the looks that designers are coming up with, that need special attention payed to there drain systems.

Copper deck drains we recommend are manufactured by Thunderbird drain. They also make an adjustable low profile deck drain with a clamping ring! Really the best of both worlds when it comes to that kind of need!!!!

copper trough 02

Now comes the the rule that seems always to cause the most problems…curb and drain height! That the drain needs to be lower than the curb,as to keep the water in the shower, make common sense, easy to do when you can stack material at the transition, achieving this for your walk in is accomplished by recessing the floor.

recessed ready on ply 02

As you can see in the photos above the recess creates the needed height difference from drain tor to floor transistion…this is where the adjustable drain or adapter comes in handy, when using a standard drain to achieve your walk in effect, and makes the linear drain lower,as it must be, when set on the recessed floor!

More on this and other special drain situations in next weeks blog!

recessed eady 02

Call us @ 866.305.4980 for any question you may have. Or better yet call me direct @ 949.485.1613 if you have a unique drain situation. Thanks for reading Jonny