Skip to Content

Why Is My Bathroom Floor Raised? (Quick Answers)

Moisture and humidity can ruin the structure and look of both the bathroom walls and the walls of the room associated with it. This is why, when you plan and design a bathroom, you need to consider a lot of aspects.

Many structural designs of different houses include raised bathroom floors. If you’ve recently moved into a new place that has a bathroom with a raised floor, you might be thinking about the reason behind it and if it’s necessary.

Bathroom floor raised

Your bathroom floor can be raised for different structural reasons. The most common reasons behind a raised bathroom floor are to allow space for the plumbing to work correctly and to create a slope for the water to drain efficiently. A raised bathroom floor is common in old houses. 

Allow space to create a slope for the water to drain quickly and efficiently: 

A bathroom is also called a wet room as you are always working with water in this room and it gets wet multiple times a day. It is important to direct the water of your bathroom towards the drain hose so it can dry quickly and water doesn’t get to stay on the floor for too long.

Creating a slope can do the work better than anything else. A bathroom floor is often raised slightly on one side to create a slope towards the drain hose so the water can drain quickly and efficiently. If your bathroom doesn’t dry properly, humidity and moisture can cause damage to the floors and the walls. 

Provide space for housing the plumbing pipes and supply lines:

Unlike regular rooms, a bathroom has lots of plumbing pipes and water supply lines. The floor of a bathroom is often raised to provide space for the pipes and supply lines. This happens when the structural format of a house is planned to accommodate the plumbing setups below the bathroom floor. 

It should not be a big problem if the bathroom floor is slightly raised compared to the adjoining room or hallway. But, if the floor is too high, it can be visually unappealing and end up causing discomfort for regular use. 

Match with the raised shower area:

In some bathrooms, the shower area is raised to separate the rest of the room so the whole room doesn’t get wet every time someone takes a shower. When a new resident doesn’t like the raised edges inside the bathroom, it can be matched by laying tiles all over the bathroom floor which will end up raising the height of the floor from that of the adjoining room. 

Structural format:

The structural format of some houses is designed in a way that they can only support plumbing pipes and supply lines when they are housed underneath the bathroom floors. This is especially true for old houses. 

It is impossible to change the design plans for some old houses as you must leave some room below the bathroom floor that requires raising the floor a bit. However, for some houses, the design can be altered. 

The floor has layers:

Oftentimes, the bathroom floor tiles have multiple layers of different materials beneath them that raise the height of the floor. Right below the tiles, there’s a layer of mortar that goes over the concrete backer board. This board can be 1/4 to 1/2 inches thick. 

All these layers sit over the original subfloor which is of the same height for the whole house. When these extra layers go on top of the subfloor, they add an extra height to the bathroom floor. Also, for some floor designs, you must apply an additional layer of plywood or tile backer which can raise the floor.


For some old houses, contractors are forced to raise the bathroom floor to follow the structure of the house. The plumbing setups are done in a way that only a raised bathroom floor can allow the room for them to work properly.

Also, some people try to get done with the remodeling of the house by simply laying tiles over tiles, roofing shingles, plywood, or backer boards. To install tiles over an existing floor, you must apply mortar to work as the adhesive for the tiles. Thus, multiple layers of materials end up raising the bathroom floor height as well.  

Should the bathroom floor be lower?

A bathroom floor should be level unless you plan to create a slope towards the drain for water to drain quickly. Uneven bathroom floors can be a bother to the users. But creating a slope is often necessary to let the water flow towards the drain that will help the bathroom to stay dry. 

The subfloor should be level as it’s very important to balance everything that goes over the finished floor. You don’t want to walk on a floor and findl it making noise or sag. If you lay tiles over an uneven subfloor, it can result in cracking and sinking of the tiles which are absolutely unwanted. 

What is the acceptable floor height difference for the bathroom floor?

If you’re designing your own house, whether or not to have a bathroom with a raised floor is completely your choice. It is not mandatory to build a bathroom with a raised floor. However, a raised bathroom floor shouldn’t be any higher than 1/2 to 3/4 inches. A floor higher than that can be bothersome and unmanageable to some extent.

If you’re moving into a new place that has a bathroom with a raised floor, it should be okay if the height stays within the limit. Some private houses can have bathroom floors 2 to 3 inches higher than the regular flooring. If it’s the homeowner’s choice, it should be fine. The tiles that are used for bathroom flooring are usually 1/4 to 1/2 inches in height. 

How to build a raised bathroom floor?

There are many ways to raise a bathroom floor, but all of them are quite time-consuming and take a lot of effort. If you need to raise a floor slightly higher than usual, you can check out the following method. 

Preparing the bathroom before raising the floor:

Before you start raising the bathroom floor, you need to turn off all the water supply valves and disconnect the pipes. Then you need to carefully unscrew and remove the sink, faucet, and vanity. 

Next, disconnect the pipe that feeds the toilet. Flush the toilet to get rid of the water in the tank. Then carefully unbolt and lift the toilet and place it on paper to not get the wax everywhere. Don’t forget to remove the bolts from the toilet flange. 

If you’re not going to install a new shower unit or a bathtub, you may not need to remove them. Remove any baseboards along the floor with the help of a pry bar. 

Measuring and cutting the OSB, backer board, or tiles:

You’re all set to start preparing for the OSB or tiles installation. For that, first, you need to measure the length and width of the floor and cut the OSB or backer board accordingly. If you’re using tiles, try to choose bigger pieces as that will both save your time and require lesser cuts. 

Marking and cutting holes for supply lines and pipes:

Now as you’re done cutting the OSB or backer board, you need to take proper measurements to mark the holes for supply lines and pipes. After marking them, cut the holes carefully. 

Applying adhesive and starting the installation: 

Now it’s time to cover the floor in adhesive and place the OSB or backer board on the existing floor. Use nails or backer screws to secure everything into place. For installing tiles, apply a second layer of the adhesive before placing the tiles.  

Reinstalling the toilet, vanity, and sink:

After installing everything properly, wait for the adhesive to dry completely. Don’t forget to use a flange extension to raise the existing toilet flange. Then you can start reinstalling the toilet, vanity, sink, and faucet in their places properly. Now you’ve got yourself a bathroom with a raised floor.  

Final Thoughts 

You can have a raised bathroom floor in your house due to various structural reasons. Oftentimes, a bathroom has a raised floor to create a slope towards the drain for quick and efficient draining. Leaving enough room for housing the plumbing setups below the floor is another important reason.