With all the options available for waterproofing your shower pan we are going to look at and compare the differences between them. Cost, preparation, installation time will be a few of the highlights we will explore. In this series of blogs, we will do a side-by-side with the most used methods in Southern California and Nevada. Starting with Hot mopping vs. Vinyl sheet goods!
Commonalities of all systems
When comparing the different types of systems to waterproof your shower pan we need to take a look at what they all have in common before we can hash out the advantages and disadvantages of each.
Proper Preparations
Framing
The carpenters will be in charge of making sure that the shower pan has all the proper backing and blocking (link to blog) needed for the correct installation. Any benches, seats, soap niches, and curbs usually fall in their scope of work. All waterproofing techniques require a solid surface to which the material to be used can adhere too. Gaps and voids create a weakness to the overall performance of the product that is being used. Those gaps and voids that are just bridged in the installation process stand a good chance of being penetrated by others working in the shower pan area.
Plumbing
The plumbers will be in charge of setting the drain and water supply lines. This can be done before or after the framers do their job. The importance of using the proper drain and placement is a critical part of the scope of work when it comes to the finished product. Drain styles and options have evolved and have given the client and/or builder a new dimension in what the finished product can look like.
(see drain blog)
The Pre-Slope
Whoever is doing the waterproofing usually does the pre-slope but not always. The importance of establishing the proper slopes (both pre slope and set slope, see blog for more info) cannot be over emphasized! Improper slope has caused many a headache for contractors and DIYers alike. The building code for pre-slope has set parameters, ¼”to ½” per foot no less and no more, beware though some cities and counties and individual inspectors prefer the use of the maximum amount per foot, as is the case for LA county and many of the surrounding cities in the Los Angeles basin. Inspectors have failed pans for not having enough pre slope, even when within the building code parameters! The pre slope is to be made of a material that forms a smooth, solidly formed subbase to accept the lining material. This gives a wide range of materials that can be used. I will go into more detail on pre slope differences and how they are made in a future blog. For now we have what most showers (there is some exceptions and it is the load bearing sheet good applications for waterproofing your shower pan that combine the pre slope and set slope in one…more on that in the future as we compare the other types of products that can be used to waterproof your shower pan)
Now that we have all the commonalities of what these systems need it’s time for the comparisons in their applications…
Sheet Goods Application
Sheet goods come in rolls that are usually 6’ wide and can be any length. With larger shower pans that will mean a seam that will need to made with adhesive that was made for the product that is being used. It can involve cleaning the mating areas of the surfaces being seamed, an large enough area to lay out and apply the solvent to be used and dry for a specific amount of time, rollers, brushes and/or dobs to for the application. Vinyl and other products of the same sort are loose laid on the pre slope. The back wall is tacked first, and the inside corners are folded in such a way as to make the turn toward curb, a bit tricky as all fasteners needed to be as high as possible on the blocking and no lower than 3” above the curb finished height. Working your way toward the curb portion of your shower pan. Some installers at this point will mark and cut out the drain opening, fold back the liner material, apply the product approved caulking to the drain, fold back and attach the clamping ring. Others will cut the drain hole out after the shower pan is fully attached and caulk and set the flange. Coming to your inside corners at the curb you will need to make your folds and secure as needed before going over the curb and down its face. This is where folds and getting the liner to lay flat and tight is difficult. Some systems have prefabricated inside and outside corners that can be seamed as joining two sheets together, so the material can be cut to have a smooth and tight transition at these difficult areas. Here are some pros and cons of this system:
PROS
- Readily available at many retail and online venues
- Comparatively Inexpensive
- Can be done by a capable DYIer
- Sometimes included in the project bid
- Fairly quick installation time
CONS
- Getting material to lay flat on walls and floor, especially corners
- Use of solvents and dry time if seaming is needed
- Transitioning from inside corners to outside corners
- Folds can be an issue due to the thickness created when folded
- Hard to use on custom shaped shower pans
- Cumbersome to fit and place
- Cure time for caulking or corner seams (if used) delays water test
Hot Mopping Application
Hot mopping is a monolithic system that uses asphalt impregnated perforated felt paper and hot asphalt (tar) to form a built-up system of 4 layers of tar and 3 layers of paper. It is bonded to the pre slope and to itself to form what is essentially a one-piece waterproof layer that can conform to almost any size and shape including odd angles, rounded and cut corners are not an issue. All seams, laps, and corners are bonded to each other by a generous layer of hot tar. Wall to floor folds are crisp and clean and stay in place. Benches, pony walls, and tub ledges blend cleanly into your shower pan creating an integrated coating of all the areas being waterproofed. All corners, wall and curb seams receive a fiberglass mesh for added strength before final topcoat of tar.
PROS
- Fast installation time when performed by a qualified technician standard 3×5 shower can be completed in 90 minutes or less.
- No waiting for mortar bed pre slope to set for installation
- Square and clean corners as material is adhered to pre slope and backing
- Multi layered system adds superior protection
- Able to do large areas and custom shapes
- Water test in as little as 3 hours after completion
- Cost is very competitive with all other methods of waterproofing
- Can be used for decks
CONS
- Specialty contractor needed to perform job
- Fumes, smoke, steam during installation
- Tar smell when applied dissipates within 45 minutes depending on ventilation
All waterproofing systems work when applied in the proper manner. Some are easier than others. Hot mopping has been used in Southern California for going on 60+ years or more. It has proved its dependability and remains the 1st choice for builders and contractors. When you or your builder hires a licensed contractor to hot mop your shower pan that is usually all that company does. Day in and day out experienced technicians that are focused on their trade and making your shower pan waterproof for years to come.
Summary
Article Name
Hot Mopping vs. Vinyl Sheet Goods For Waterproofing Showers
Description
With all the options available for waterproofing your shower pan we are going to compare hot mopping to vinyl sheet applications.
Author
Jonny Gautney
Publisher Name
DK Shower Pans
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