What Is a Shower Pan

If you have recently purchased a house and your inspector has told you that your shower pan needs replacement because it is leaking; the first question you will have on your mind is what is a shower pan? And why does it leak? After all, aren’t shower tiles meant to be waterproof? This is a common question that most homeowners need to face at least once in their lifetime.

What is a shower pan? In this guide, we will talk about shower pans, the uses of shower pans, their different types, and also cover the steps for installation of shower pans. Without further delay, let’s dive deep into the topic!

What Is a Shower Pan?

A shower pan is placed beneath the ceramic tiles of a shower enclosure. It is made of different materials like composite, acrylic, lead, metal, etc., and placed in the shower enclosure’s framing. A shower pan also moves up and under the shower walls and receives the shower tiles. That brings us to your next question: why do we need shower pans if we already have waterproof ceramic tiles?

The answer: although your ceramic tiles are waterproof, without a shower pan beneath it, the water could still seep in through the grout, cement, and joints between the tiles. A shower pan is especially necessary near the drains to prevent seepage of water through the drain joints.

Over time, shower pans start to leak due to the chemicals in hard water. High-quality shower pans can last several decades provided you have installed them right in the first place. Building codes also require you to install shower pans based on the local construction zone rules.

What Are the Uses of Shower Pans?

Shower pans are a compulsory part of shower installation in most cities and as per building codes and permits. Here are their uses and benefits:

They Make Your Shower Safer

Without shower pans, the water will not drain off completely after you use the shower. This can lead to puddles of water on the shower floor. Water puddles can make your tiles very slippery which can lead to dangerous, even fatal, slips and falls. If you have elderly people living in your house, then it is extremely important to ensure that your shower pans are not leaking.

They Prevent Mold

If shower pans have failed or developed leaks, you are highly likely to have a mold problem. Mold in bathrooms can be very dangerous as it can cause a variety of health issues. Some of the dangers of mold are allergic reactions like itchy, watery eyes, runny or blocked nose, difficulty breathing, headaches, asthma, etc.

In severe cases, mold can also lead to poor concentration, severe skin rashes, ringworm infection, and digestive problems as well. Mold can negatively impact the health of kids and elderly and could even harm your pets. With high quality shower pans in place, you can prevent mold formation and make your bathroom safer and healthier.

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They Are a Necessity as Per Building Codes

Shower pans are legally needed in many cities and as per local building codes since they prevent structural damage caused by leaks and water seepage. Most building codes even have specific dimensions for the pans.

So, if you are planning a shower remodel, it is a good idea to contact your local building office regarding the dimensions. Most shower pans are 1024 sq. inches or 32 x 32 inches. If you are replacing a pan smaller than that, depending on your local building inspector, you will be able to use one that is the same size as the original.

It Is an Essential Part of a Steam Room/Sauna

A shower pan is an extremely important component of any steam room, steam shower or regular shower and may be required per building code. Without a shower pan, you could face water seepage which, in turn, can cause health issues/mold/structural damage.

This is because; steam will eventually condense into water, and thanks to gravity, will eventually seep through. If the shower pan is not present, or its vapor/moisture barrier has failed, then the water will eventually end up on the outside -on the shower floor and walls. This can lead to a plethora of issues – health, structural damage, and very expensive medical bills and repair costs.

Types of Shower Pans

There are three types of shower pans:

Conventional Type

This type of shower pan liner covers the shower floors and wraps up the walls about 7-inches high, leaving about 2-inches over the threshold which is about 5-inches in height. The shower pan wraps up and over the threshold and up the side walls above the threshold.

These types of pans are typically made of PVC. Another material used in conventional pans is Chloraloy which is a rubber like material designed specially for showers. Once the conventional shower pan is installed, 2-3 inches of mortar is poured into the pan.

Topical Membrane Type Pan

A second type of shower pan uses a reinforced fabric liner or a rubberized membrane that goes over the mortar bed or a type of preformed Styrofoam made to slope the drain. These types of pans come in full ready-to-install kits.

Liquid-Membrane Type Pan

A third type of shower pan uses a liquid membrane that is painted or troweled on the mortar base. The membrane becomes a type of rubber coat that forms a layer over the mortar and continues up the cement backer boards like a topical membrane. Generally you need two coats of liquid rubber.

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Shower Pan – Details of Installation

We have covered the installation of conventional shower pans below. Note that the steps of installation will vary based on the material of shower pan used. In fact; there are three methods for installing each of the types of shower pans mentioned above. Each method will work well if the steps are carried out properly.

Add the Mortar Bed

Under the shower pan is a mortar bed installed to pre-pitch the floor. This ensures proper drainage of the water through the drains’ weep holes. Without this step, water can sit in the low corner of the tile base for years.

Prepare the Shower Pan Base

Staple or nail down a layer of tar paper and galvanized wire lath to lock down the cement mortar in place over the plywood floor. Then add the dry pack (cement mortar) and level and pitch it to the floor.

Use a steel floating trowel and a wood float to pack in the cement mortar tightly. Once you have packed and leveled the mortar base around the perimeter of the pan area, you can use a smaller level to pitch the mortar to the drain base. As a rule of thumb, allow ¼ inch to each lineal foot.

Install the Pan Liner

Lay the liner out and center it in the shower area. Measure and cut it keeping in mind that it needs to come up about 7-inches along all of the walls. Where the floor meets the walls, leave the liner not taut but slightly folded squarely. (There should be no pressure from the liner pulling outward from the floor/wall junction).

Lay the Custom Shower Pan

Tack in the custom shower pan using galvanized nails. Keep the membrane flat and even by moving from one stud to another ensuring that the membrane does not bunch up. The nails should always be at the top of the pan and never below the top of the threshold. (One of the most common shower pan failure reasons is the nails put in below the water line).

Attach the Prefab Corners

Prefab corners are available readily but if you can’t find them, ensure that the membrane still wraps up on the walls. Failure to do so can cause the wood to shift. This tiny shift can cause leaks in the future.

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Pack in the Dry Mortar

Set the drain and test the custom shower pan with water. Now add the dry mortar and level it around the perimeter. This process is very similar to the pre-pitch dry mortar except that the mortar on the pan is 2-to-3 inches thick. On custom shower pans larger than 3 ft x 4 ft, add thin rebar to add strength to the thick mortar slab.

Install the Cement Backer Board

Have a sample of tiles you are planning to install. This will give you an idea about the exact mortar base you need. Some tiles are less than ¼ inch thick; others may be up to ½ inch thick. If you pour and level the mortar base before knowing your tile thickness, it could make the tile stand above the drain cover.

Conclusion

In the past, bathroom shower pans were made of lead or copper. These would deteriorate in 15 to 20 years but their repairs would be as expensive and difficult as their reinstallation. It was also difficult to match them to the original tiles and so homeowners would have to even change the tiles. This would end up being a very costly project.

Today, manufacturers have come with different types of shower pans and each one has different steps of installation. Each method, as mentioned above, will work correctly if all of the steps are carried out properly. We hope the above guide helps you successfully install your custom shower pan. If in doubt, do not hesitate to seek professional help.