How Much Weight Can a Shower Base Hold?

The bases of showers, also called shower pans have been reported by many people to crack under the weight of a large person. This is more so true for acrylic and fiberglass shower bases. In this article, I will explain how much weight a shower base can hold.

On average, a tiled shower base can withstand 250 pounds per square inch (45.2 kg per cm squared), which is roughly 4500 kg over a small shower. Fiberglass and acrylic shower bases can withstand about 300 lbs (136 kg). But, check with the fiberglass or acrylic shower manufacturer, as it does vary. 

There are four main types of materials used for a shower base. There are also methods of installing a fiberglass or acrylic shower base that will reduce the chances it will break. Below, I will explain which type of shower base can hold the most weight.

What Type of Shower Base Can Hold the Most Weight

Shower pans are typically made of either acrylic, fiberglass, tile, concrete, or composite. Each of these different shower pans has a different weight capacity. Here are the long and short of which kind of shower pan material is the strongest.

tiled shower base

Overall, tiled or concrete shower bases can hold the most weight. A properly installed tile or concrete shower base can hold a virtually unlimited amount of weight without failing. On average, about 250 pounds per square inch (45.2 kg per cm squared).

A small shower is 3 feet by 3 feet (1 meter by 1 meter). Based on the load tiles can take, this means a tile or concrete shower base could hold the weight of 45 large people who are 220 lbs (100kg) each. This is more than enough for 1 person and is the best option for a large person.

Calculating the exact load tiles can take gets a bit tricky, because of the measurements they are given in. But, there are various building standards for tile installation which means tiles need to have a minimum weight capacity. 

It’s worth pointing out you may have seen in shopping malls, sometimes they will drive and park a car on the tiled floors in a mall as a promotion. A car weighs in the range of 2500 pounds (1000 kgs). So, tiles can have no problem holding the weight of even the largest person.

What a composite shower base is

Porcelain shower base in a bathroom

In shower base terminology a composite shower base is one made of one or more materials. These materials can be ground stone, quartzite, and resin. Typically, they are a concrete type material. That has a natural stone look. 

These can generally hold much more weight than a fiberglass or acrylic shower base. And are about as strong as concrete or tile. However, because there are so many different materials used to make them, the weight capacity differs quite a lot. For these, it’s best to check out the specs for major brands that make them.

An acrylic or fiberglass shower base is typically not suitable for someone who weighs a lot – over 300 pounds (136 kg). Therefore, before deciding on a shower base, it’s important to know how much the heaviest person in your household weighs. In general, if you have heavier people in your household you should have your shower base tiled.

It does somewhat go without saying, but it’s important to have the tiles installed correctly. It’s common for incorrectly installed tiles to crack under too much weight. This is because the adhesive on the underside of the tile has spaces in it. 

When too much pressure is applied to tiles with open spaces in the adhesive underneath, the force isn’t spread evenly over the whole tile. It creates a weak area in the tile, that is more likely to crack. 

How to stop a fiberglass/acrylic shower base from breaking

cracked acrylic shower base
Image from Steve Plumbing

A fiberglass and acrylic shower base have a maximum load that can be close to how much a person weighs. Expert plumbers have provided details about how to reduce the chances that it will crack under heavy loads. The main thing is what is installed underneath it. If there is simply wood, plywood, or concrete underneath there will be a gap between the shower base and the floor. 

This provides room for a fiberglass or acrylic shower base to bend a lot which makes it more likely it will crack. Therefore, plumbers have recommended putting either sand or mortar underneath. This will take up the space, and absorb the weight a bit. It also allows a fiberglass or acrylic shower pan to bend a little bit without cracking.

Should a Shower Base Flex

Shower bases can be made of a few different materials. White acrylic or fiberglass shower bases are very common. When showering you can notice that it bends and flexes, but is this normal for an acrylic or fiberglass shower?

As a general rule, a shower base should flex. However, for heavier people, mortar or sand should be installed under a shower base. It will stop a shower base from bending a lot which can make it crack. But, fiberglass and acrylic shower bases have a maximum weight capacity.

A shower base can technically be installed directly onto a concrete floor, or with plywood underneath. This will cause it to flex and bend more than if mortar or sand are used underneath.

How Much Body Weight Can a Fiberglass Shower Hold

Some people are very tall and muscular or have a few extra pounds. A shower base tends to creak and bend slightly when a person stands on it. So, here’s how much body weight is too much for a fiberglass shower.

On average, a fiberglass shower base can hold 300 lbs (136 kg). But, this does vary based on the brand. To be sure it’s best to check what the maximum weight is with the manufacturer. Fiberglass and acrylic shower bases are known to crack under too much body weight.

It’s best to limit the number of people that use a fiberglass or acrylic shower base to one at a time. Otherwise, the extra weight can cause it to crack, as can be seen in the weight capacity specs of a typical acrylic shower base such as this one made by Delta Faucet

If you’re getting a new shower and you’re a larger individual, or someone in your household weighs a lot then it’s best to get a tiled or concrete shower base. Tile can hold virtually unlimited body weight.

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