What Is A Wet Room Former? | Everything Explained

You are planning on adding a wet room design to your bathroom renovation plans. But, how do you get the water to drain from a flat seamless floor? A wet room former is used to build a floor able to direct water to the waste pipe and save you or your contractor hours of creating the proper slope.

In this post, I’ll explain what a wet room former is, how it’s installed as well as go over some common questions around the topic.

Let’s dive in!

What Is A Wet Room Former?

The former is a single piece of glass-reinforced or moulded concrete with a stiff foam core and serves as the first part of waterproofing or tanking your wet room. It is the size of your projected walk-in shower.

Once installed, it will be hidden by your flooring material. It provides a seamless transition between the gently sloped floor of the shower with your tiled, concrete, or vinyl floor.

The former has a hole precut to accommodate your shower drain and many kits include the parts needed to connect to your main waste while fitting the drain cover to the perfect height.

The former itself does not serve to waterproof or seal the shower area. It is designed for the purpose of creating an effective slope for directing the flow of water.

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How Is A Wet Room Former Installed?

Whether you are working with a timber or concrete subfloor, the wet room former is installed before you begin levelling the rest of the floor.

The area for the new walk-in shower is marked out.

The position of the drain is determined and a gully is cut into the concrete floor or pipes run through timber supports. The vertical trap for the drain is checked for height.

Noggins are added between the rafters and around the perimeter of the former to provide added support to the former and the drain.  Every support must be precisely level.

The former is screwed into place and the drain secured.

The wet room is now ready to be tanked and have the final floor installed.

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Considerations When Choosing A Wet Room Floor Former

If you are tackling this job as a DIY project, using the proper former will determine the success of your final wet room design. There is a wide range of formers on the market and some are designed for more specific applications than others.

Before shopping for the former, decide on the size and shape of your walk-in shower. Formers are sold in an array of standard sizes from 700mm x 700mm to 1500mm x 900mm. There are options for circular and hexagonal showers. The drain can be a long rectangle instead of the traditional circle.

If your design does not quite fit the standard size, most formers can be trimmed down for your needs. However, if the former is slightly larger than the shower, there is no need to downsize as it will be completely hidden under the flooring.

You will need to look for a few product details when buying the former based on the existing floor and structure of your home.

Wet Room Former for Concrete Floors

You will be building up the entire floor of the bathroom to match the level of your wet room former. This can be time and cost-saving over chopping out the existing concrete. You can use a prefabbed former designed for concrete or opt for a modular former set over which you will pour new concrete. The former is a better option for a DIY project. Pouring concrete is not difficult, but levelling and smoothing the surface takes a practised hand.

Once the former is in place, the rest of the wet room floor is poured to come up to the level of the former. You are then ready to lay the vinyl or tile floor.

Concrete floors mean that you will be chipping out a gulley for the drain pipes. There is an extended cure time needed before you can move forward with the rest of the project–sometimes up to several weeks.

Wet Room Former for Timber Floors

In this case, the timber refers to the hidden structure of the floor–not the final surface. You will purchase a former that is the same depth as your existing floorboards plus the thickness of whatever stone, tile, or vinyl you may be used for a finish.

You will need to take notice of the intended position of the drain. It must be located between a pair of joists. You will need to measure the location before buying the former. Some formers include an offset pre-cut drain hole so that you can simply flip the former to get it to line up with the proposed drain site. 

The former must be fully supported all around its edges and around the drain by adding extra noggins between the joists.

Once the drain is installed and the former screwed into place, you are ready to proceed with tanking the wet room.

Wet Room Former for a Vinyl Floor

This approach is very similar to working with timber floors. Whether the vinyl will be installed over timber or concrete, you simply need to select your former to accommodate the thickness of the vinyl on top of the subfloor.

This may range between 2mm to 8mm. The key here is to have your flooring selected before you purchase the former. A rolled vinyl floor can cover the entire wet room to create an affordable and seamless surface.

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Does A Wet Room Have To Be Tanked?

Yes and no. Since most wet room designs do not include a shower enclosure, tanking the room protects your walls and subfloor from water damage when somebody has too much fun. In a large spa wet room, you may be able to tank only half the room where it is likely to have spray from the shower.

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Final Thoughts…

There you have it! Everything you need to know about the trusty wet room former.

While not essential, wet room formers can be a great option to ensure you get a perfect gentle slope towards your drain in your wet room or shower area. They’re available in a huge range of sizes and drain styles so you’re bound to find the perfect pick for your new wet room.


Michael R

Michael is a KBB designer from the UK. He's been designing and project managing new Kitchen, Bedroom and Bathroom installations for over eight years now, and before that, he was an electrician and part of a KBB fitting team. He created The Bathroom Blueprint in early 2020.