Do I Need a Riser Kit for Shower Tray? Expert Guide
Installing a new shower tray often brings up the question of whether a riser kit is necessary. This small component, usually a simple plastic or metal ring, sits beneath the tray to increase its height. The primary purpose is to create a perfect transition to the finished floor level, ensuring a flush surface that prevents tripping hazards.
Understanding the Role of a Riser Kit
The core function of a riser kit is to solve a discrepancy in elevation. Most standard shower trays are designed to sit lower than the desired final floor height. Without adjustment, this creates a dip where water can pool and the tile finish appears uneven. By adding layers, the riser effectively lifts the tray to sit level with the surrounding tiles or waterproofing membrane.
When a Riser Kit is Essential
You will likely need a riser kit if your floor finish is thicker than the tray's designed mounting height. For example, if you are installing a thin stone tile that results in a 20mm floor finish, but your tray sits 50mm above the subfloor, you have a 30mm gap to bridge. In this scenario, the riser is not just helpful; it is critical for structural integrity and water drainage.
- Thick Tile Setter: Modern cementitious tile adhesives and large-format tiles can add significant depth.
- Stone or Solid Surface: Natural stone or quartz composite floors sit higher than standard vinyl or grout.
- Subfloor Level: If your existing subfloor is uneven or slightly raised, the riser helps standardize the height.
Consequences of Skipping the Riser
Installing a tray without the necessary elevation can lead to functional and aesthetic problems. A tray that sits below the finished floor creates a small basin at the doorway. This geometry encourages water to escape the shower area, potentially damaging the surrounding flooring and causing slip hazards.
The Gap Under the Tile
If you force the tray to sit on a sloped subfloor without a riser, you create an angle that prevents the tile bed mortar from filling completely. This gap compromises the bond between the tile and the tray, increasing the risk of cracking, loosening, and eventual failure of the waterproofing layer.
| Floor Finish Thickness | Standard Tray Height | Riser Kit Required (mm) |
|---|---|---|
| 10mm | 50mm | 0 (Standard fit) |
| 20mm | 50mm | 30 |
| 30mm | 50mm | 20 |
Compatibility and Installation Tips
Not every shower tray requires the same solution, so checking compatibility is vital. Refer to the manufacturer's specifications for the specific model you purchased. Many premium trays are designed with integrated height options or flexible base systems that minimize the need for bulky risers.
When you do use a riser, ensure it is seated firmly beneath the base of the tray and covered with a sufficient amount of flexible sealant. This creates a waterproof perimeter and absorbs any minor movement of the structure, preventing cracks from forming at the joint between the tray and the riser.
