What to put under a shower base?

Author: Jennings Ullrich  |  Last update: Tuesday, October 21, 2025

Cut a sheet of building paper or roofing felt to fit the bottom of the shower base to act as a cleavage membrane. Install metal lath or reinforcement over the cleavage membrane, securing it to the subfloor with nails or staples.

What does a shower base sit on?

For a shower pan installation, your product might require the pan to sit directly on an adhesive or on small piles of thin-set mortar. If your shower pan installation requires an adhesive, spread it throughout the area where it will be placed.

What is best to lay a shower tray on?

For low-profile shower trays that sit directly on the floor, you typically do not use cement. Instead, you create a mortar bed using a mixture of sand and cement to support the tray. However, for adjustable-height shower trays with legs, cement is not required, as they are adjustable and self-supporting.

How do you fill a gap under a shower tray?

Ensure the base, wall & gap are clean of debris. Use sanitary silicon sealant (various colours available, but white is usual). Using a caulking gun, apply an even bead along the gap. If the gap is larger (9mm as you mentioned), the build it up below the tray level a bit, before putting the final bead on.

Is it necessary to put mortar under a shower base?

No. The shower base is designed to rest directly on the subfloor. Only if the floor is unlevel would mortar or leveling compound be needed. A general "sand mix" mortar type will be sufficient.

How to Install a Shower Pan | The Home Depot with @thisoldhouse

What should I put under my shower base?

Cut a sheet of building paper or roofing felt to fit the bottom of the shower base to act as a cleavage membrane. Install metal lath or reinforcement over the cleavage membrane, securing it to the subfloor with nails or staples.

What is the best cement for under a shower base?

SAKRETE Sand Mix is ideal for shower bases. lt is a high-strength, pre-blended mixture of Portland Cernent and sand. This product can be used where a thickness of less than 5 cm (2 inches) is required.

What is underneath a shower tray?

A shower waste (often also referred to as a "shower trap") connects to the underside of the shower tray beneath the floor of the shower and works to support the water flow.

How do you fill a gap between a shower pan and the floor?

If it's a huge gap, you can fill most of it with grout (leave a narrow gap against the tub), let it set, then caulk the remaining gap with silicone. I would try a pre mixed grout. They tend to stay put and crack less. Also easier to clean.

What goes under the shower pan liner?

In a typical shower construction model, there are five layers to the shower floor: the subfloor; the slope base or first mortar bed; the shower pan liner; the final mortar bed; and shower tiling or floor.

What is the difference between a shower base and a shower tray?

Both a shower pan and a shower base direct the water towards the drain. The key difference between the shower pan and shower base is the location. The pan is the actual floor of the shower, while the shower base is beneath the pan and is part of the bath substructure.

What board to use under a shower tray?

– Unlike plywood, which has seen a reduction in quality, NoMorePly 12mm fibre cement boards are recommended for their strength and moisture resistance.

What's best to stick a shower tray down?

Use installation compound adhesive or a suitable contact adhesive to cover the full area under the shower tray. Apply or trowel to a thickness suitable to allow full adhesive support of the shower tray. Note! Always follow the instructions supplied with the adhesive.

Which is better, a shower pan or shower base?

The Pros and Cons of Each. There's no right answer on whether an acrylic shower pan or tile base is best. In general, shower pans are much more affordable, but this also means that they're less customizable. They generally just come in one standard material and color option.

Can you put a shower pan liner over plywood?

Applying a waterproofing membrane over the plywood floor is vital to ensure a completely watertight shower pan. Here's how to do it: 1. Measure and cut the membrane: Use a tape measure to determine the required dimensions of the waterproofing membrane.

What holds shower base in place?

Now you're ready to secure the shower pan in place. Some shower pans use clips or screws to fasten the pan to wall studs. For our project, the shower pan secures to the subfloor with mortar. Mix enough mortar to apply to the installation area.

How to fill a gap under a shower tray?

How To Seal A Large Gap Around A Shower Tray? Sealing a large gap around a shower tray demands a gap-filling sealant. Select a sealant designed for substantial gaps. Apply it generously to fill the space, ensuring complete coverage.

Should you caulk the base of a shower?

If you have a pre-fabricated shower pan, such as one made of acrylic or fiberglass, you should definitely caulk between the tile and the pan. These types of pans have a lip that is designed to fit under the tile, and the caulk helps to seal this area and prevent water from getting underneath the pan.

Does shower pan sit on subfloor?

Prepare the Subfloor

The entire bottom of the shower pan needs to sit on a flat, level surface. Check the subfloor area from left to right and from front to back to make sure it's level.

What to use under a shower base?

The majority of shower pan manufacturers recommend installing a bed of mortar under your shower pan. Besides providing a satisfyingly hard floor for your shower, a mortar base will also protect your subfloor from water damage, mold and even rot.

What is the best flooring for under shower tray?

Tiled Floor. The most common choice of flooring finish when it comes to a wet room or walk in shower is tiles. A tiled floor finish also means that you have the widest choice of under tray / wet room tray available as nearly all wetroom trays are designed to accept at least a tiled floor finish.

What goes under shower floor?

Answer. A waterproof membrane or liner is typically installed under a shower floor to prevent water from seeping into the subfloor. A sloped mortar bed often follows this to ensure proper drainage towards the shower drain.

What kind of quikrete do you use for a shower pan?

QUIKRETE® Sand/Topping Mix (No. 1103), in conjunction with QUIKRETE® Concrete Acrylic Fortifier (No. 8610) replacing half of the required water content, is the combination of products recommended for a shower pan.

What kind of adhesive do you use for a shower base?

We recommend the use of advanced polymer or hybrid sealants and adhesives safe for plastics for installation. Adhesive and Sealant - look for an "advanced polymer" or "hybrid" product that does NOT clean up with water.

What is sand mix good for?

The versatility to tackle more projects with a single mix – that's Sand Mix. This pro-grade concrete mix is formulated for high strength without large aggregate, making it ideal for use in repairing cracks, slab resurfacing, mortar bedding, forming shower pans, and more.

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