What do you put under a Shower base?

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A bathroom’s aesthetics is not complete without the addition of a shower pan. Either it is a renovation or a completely new installation, shower pans are one of the things you can fix yourself around the house.

There are a few simple steps to fix a new shower pan yourself.

But you may be wondering, what should I put under the shower base?

To safely install a new shower pan, put mortar under the shower base. First, fit in a waterproof liner on the floor. Then cover it with mortar before fitting in the shower base. Allow it to dry for a day, and behold the new shower pan.

Yes, it is quite simple, but you need to learn the intricacies. It is important to have the right things in the right place. The mortar must be the appropriate mix for perfect water retention and durability.

There are different types of shower pans. Some can be tiled, while some cannot be tiled. Read on to know more about getting the shower pan rightly fixed.

Is the shower base different from the shower pan?


Oftentimes, shower base and shower pan are taken to mean the same thing.

But they are not the same. The shower pan is the material that forms the shower floor.

It is made of fiberglass, aluminum, or it is acrylic.

The shower base, on the other hand, is the underside of the shower pan. It is the patterned side that allows the pan to sit well into the mortar layer.

It is important to have a waterproof liner on the subfloor before fixing it in the shower base.

There are two types of shower pans. One type can be tiled while the other cannot. The acrylic shower pan cannot be tiled, while there are options to tile the aluminum and the fiberglass materials.

Ensure to have a shower pan that can be tiled before going on with it.

Can thin-set Mortar be used under a shower base?

A thin-set mortar is not appropriate to be used under the shower pan. This type of mortar is ideal for setting tiles on walls and floors.

It can rather be used for tiling your shower pan after fixing the base with the right mortar.

The thin-set mortar has latex and polymer adhesives added to it. These adhesives aid the attachment to the surface but not with a shower base.

The shower base needs a stronger mix of mortar.

What kind of Mortar do you use under a shower base?

Sometimes, purchasing a shower pan kit comes with a mortar mix. This removes the worry of what mortar is best to use. In a case when there is no mix available. You have four different options of mortar mixes.

The types of mortar mixes are based on the different proportions of sand, cement, and lime each contains. This proportion is responsible for each type’s durability, water resistance, flexibility, and strength.

There are three types that are good to be under a shower base.

Type N

SAKRETE |Mortar Mix Type N | 40 lb

Type N mortar is available here on Amazon!

This mix of mortar contains one part of both cement and lime with six parts of sand. It is best suited for general use. It has a good level of water resistance, strength, flexibility, and durability.

It can be used for both interior and exterior fittings. It is then a good choice to go under the shower base.

Type M

The type M mortar mix is made with three parts of cement with one part of lime and twelve parts of sand. It has the highest holding strength of all the mortar mixes.

It is a suitable choice for foundations and holding walls, seeming too sturdy for a shower base job.

Type S

The type S mix is similar in strength to the type N mortar. It is made from two portions of cement, a portion of lime, and nine portions of sand.

It is good for outdoor works and areas that are liable to get wet. It can be used for shower base fixing.

The fourth type of mortar is type O. It is best suited for indoor fixes. It is used for fixing cracks and holes. It has the least strength of the four mortar types.

It is made with one part cement, two parts lime, and nine parts sand.

How thick should the mortar be under a shower base?

The consistency of the mortar that is used under the shower base is important. The right thickness and mortar type will help keep the shower pan in the best condition.

Out of the four mortar types, types O and M are too weak and too strong, respectively.

The mortar must not be too strong to allow the shower pan to set properly. It must not be too soft at the same time to hold the shower pan in place.

Type N and S are good for the job, but how much water needs to be added?

Read this to get the consistency right for the mortar to be used under the shower base. You need to add enough water to the mortar mix to activate the cement in the mix. But it must not get too wet.

Add enough water to make the mix feel like the sand used to build castles by children. Wet enough to be molded into a ball that falls apart after few seconds.

A consistency similar to a shea butter mix is perfect. It is possible to get the exact mix of mortar and water recommendations in a shower pan kit.

What goes under the fiberglass shower base?

It doesn’t matter what material the shower pan is made of. Mortar is to be put under the shower base. The mortar is to help the shower pan set in place.

And also to create a waterproof layer between the subfloor and the showering unit. It must be strong enough to bear the weight.

Shower pans made with fiberglass are strong and long-lasting. Fiberglass is a material that is able to withstand stress. It is a reinforced polymer composed of glass fibers that are embedded in a resin mesh.

It is strong but must still have mortar added to its base.

Mortar under the fiberglass shower base will help its longevity of use. The surface on which a shower pan sits must be level.

An uneven surface under the shower pan can lead to it cracking under the weight and frequency of use.

So it is not just about the quality of material the shower base is made of. The surface sits on must be even and strong.

Do you need waterproof under the shower pan?


Shower base liner is available here on Amazon!

It is important to have a waterproof pan liner. To avoid having a leaking bathroom, waterproof liners must be used under the shower base.

The liner is to be placed on the bathroom floor even before adding the mortar.

Waterproof liners are made of polyvinyl chloride, a plastic polymer. It comes in different thicknesses and sizes. The appropriate size will depend on the dimension of the shower cubicle or shower pan to be installed.

It is layed below the drainpipe, and on it goes the mortar mix. The waterproof liner prevents water leakage into the floor of the bathroom.

It ensures the only place the water goes through is the drainage pipe.

How do you fix the shower pan?

Let me give a short guide on the steps to take in fixing the shower pan in place. The first thing is to prepare the bed in which the shower base will sleep. Without this, there is no fixing.

If it is a renovation, the old shower pan must have been removed. Then do the following:

  1. Clear the debris off the floor to have a clean surface spacious enough to contain the shower base.
  2. Fit in on the floor a waterproof shower pan liner leaving the drain pipe open.
  3. Fix into the shower base the drain using the plumber’s putty. Ensure it is well fitted.
  4. Pour the mortar mix on the liner to about an inch thickness, ensure not to cover the drain hole
  5. Fix the shower base on the even mortar layer.
  6. Leave to dry for a day. The shower pan can be supported until it dries.

Can you have tiles under the shower base?

There are shower pans that come with tiles, and there are others that can be tiled. But for tiles to go under the shower base? I don’t think so. Having tiles under the shower base will leave spaces under it.

The shower base is not a smooth surface. It has grooves to allow it to set well in the mortar, not on tiles. To avoid mold growth and water leakage, the shower base should sit on mortar and not tiles.

The tiles will also not allow the base to fit in, and it can make the pan not last.

Instead of having tiles under the shower base, the inside can be tiled. Only the acrylic shower pans cannot be tiled.

If your shower pan can be tiled, so go ahead and add the extra touch.

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