Many homeowners find themselves needing to raise their existing shower floor for various reasons. Most commonly, it becomes necessary when renovating an aging bathroom. Over time, shower pans can crack or leak, the mortar bed under the tile can disintegrate, or the substrate itself may begin to sag. When problems like this occur, the best solution is often to remove the old shower pan and raise the shower floor to the proper height. Luckily, with careful planning and the right materials, raising an existing shower floor is quite achievable as a DIY project.
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Why Would I Need to Raise My Shower Floor?
There are a few common reasons you may need to raise the height of your current shower floor:
To Fix a Leaky Shower Pan
The shower pan is the base that catches and diverts water from your shower to the drain. Shower pans are typically constructed from acrylic, fiberglass, cultured marble, or mortar. Over time, any of these materials can become damaged or deteriorated and start to leak. Replacing just a shower pan is difficult, so the best solution is usually removing it entirely and building up the shower floor to the proper height with new waterproofing materials.
To Replace Damaged Subflooring
The subfloor beneath your shower pan provides structural support and a substrate to adhere the pan to. Wood and plywood subfloors can eventually sag, rot, or become damaged from moisture exposure. In these cases, the subfloor needs to be replaced and the shower floor raised to match the new height of the subfloor.
To Correct Improper Sloping
Showers require a sloped floor to ensure water drains properly. Minimum slope requirements are typically 1⁄4-inch per foot. Over time, sagging, movement, or improper original construction can result in areas that don’t slope adequately towards the drain. By raising the shower floor, you can achieve the ideal slope needed for proper drainage.
To Accommodate New Tile
If you’re replacing your existing shower tub or surround with new tile, the thickness of the tile, thinset, and any backing board will raise the overall height of the walls. To allow the new shower floor to sit flush with the walls, it will need to be raised by the thickness of the new tile assembly.
For Accessibility
Raising a shower floor can help create an accessible, walk-in shower. Eliminating the step over a tub threshold makes entry and exit safer and easier for those with mobility issues. Raising the floor also allows for installation of a linear drain along the entire entryway.
To Match Adjacent Floor Heights
If your bathroom or other surrounding floors were raised during a remodel, you may need to raise the shower floor to match the new height. This helps provide a seamless transition between the shower and bathroom.
How High Can I Raise my Shower?
Most building codes allow 1⁄2-inch to 1-inch variation between adjoining floors. With this in mind, there are a few factors to consider when determining how much you can raise your shower floor:
– Drain Height – Local plumbing codes dictate how much the drain can be raised to still tie properly into the waste line. In general, you can safely raise the drain 4-6 inches before needing to modify below floor plumbing.
– Doorway Thresholds – Any doors leading into the shower should have sufficient clearance over the new raised floor. Check that raising the floor won’t cause clearance issues.
– Surrounding Floors – As mentioned above, you don’t want more than 1-inch difference between the new shower floor and adjoining floors.
– Plumbing – Check that raising the floor won’t interfere with supply lines or cause any plumbing fixtures to sit too high or low.
– Shower Pan Dimensions – Pans come in set dimensions. Make sure you have enough remaining vertical space to accommodate the new pan above the raised floor.
In most cases, you can safely raise a shower floor 1-4 inches without issue. Anything beyond 6 inches may require extensive plumbing modifications.
How to Raise a Shower Floor
The process for raising a shower floor includes removing the old shower pan, building up the subfloor to the desired height, installing new shower drainage, and adding the new shower pan and tile. Here are the basic steps involved:
1. Demolish the Existing Shower
Begin by completely removing the shower pan, any tile, cement board, and vapor barriers. Remove adjacent flooring as needed to access the shower subfloor. Demolishing down to the joists or subfloor provides a blank slate for the new shower.
2. Inspect and Repair Subfloor
With all shower materials removed, thoroughly inspect the subfloor for any damage or deterioration. Repair any sagging joists or rotten subfloor with new material.
3. Add New Blocking
Since the raised floor will likely span over joists, add new 2x blocking between them as needed to adequately support the perimeter of the new shower floor.
4. Build Up Subfloor
Use suitable materials like exterior grade plywood, cement board, or vinyl waterproof tile backer to build up the subfloor height to the desired level. Secure layers together with construction adhesive and screws.
5. Install New Drain
Install a new drain assembly at the planned drain location. You may need an extension kit to accommodate the raised height. Ensure all drain connections are secure and watertight.
6. Add Mortar Base
Install a mortar bed pitched 1⁄4-inch per foot towards the drain. This provides a stable, sloped base for the shower floor for proper drainage.
7. Waterproof the Floor
A critical step is applying a waterproofing membrane over the entire shower floor up onto the walls. Materials like Chloraloy, RedGard, or Kerdi are ideal for waterproofing tile shower assemblies.
8. Install New Shower Pan
For molded shower pans, carefully set the new pan in place fully supported on the built-up floor. Ensure the pan is level and make any necessary adjustments.
9. Install Tile, Walls, and Fixtures
Finally, install your finish shower materials – new tile, shower walls, niches, and plumbing fixtures. Take care to waterproof all joints and seams.
10. Make Final Connections
With the shower complete, make drain and water supply connections. Seal all seams and openings. Let materials fully cure before using the shower.
How Much Does it Cost to Raise a Shower Floor?
Here are the approximate costs for materials needed to raise a standard bathtub-sized shower floor:
– Demolition – $200-300
– Lumber and Backerboard – $100-150
– New Drain – $50-200
– Mortar and Cement Board – $100-200
– Waterproofing Membrane – $150-300
– New Shower Pan – $300-1000
– Tile and Additional Finishes – $500-2000
In total, expect to spend $1500-4000 or more to raise a shower floor 4-6 inches. Hiring a contractor usually costs $4000-$9000. Complex drainage modifications can also significantly increase overall costs.
Can I Do This Myself?
While labor intensive, raising a shower floor is a DIY-friendly project for an experienced homeowner. To ensure success:
– Have confidence working with plumbing, waterproofing, tile, and other wet environment materials.
– Allow sufficient time – expect the project to take 2-5 days.
– Research local building codes – permits may be required if modifying plumbing.
– Carefully follow waterproofing product instructions. Improper waterproofing can lead to major moisture damage issues.
If you are uncomfortable doing full demolition and rebuilding of the shower, consider hiring a contractor to assist with portions of the project.
Tips for Raising a Shower Floor
Here are some additional tips to help your shower floor raising project go smoothly:
– Take photos before demolition so you have a reference of how everything was originally assembled and connected.
– Wear proper safety gear – gloves, goggles, N-95 mask, ear protection. Demolition can be dirty work.
– Inspect for mold or rotted framing which may require remediation or replacing adjacent building materials.
– Make clean 90-degree cuts when removing building materials to make re-integration of walls and fixtures easier.
– Properly dispose of all old shower materials according to local regulations. Most can’t be recycled.
– Carefully follow all manufacturer instructions for Slope, drainage, waterproofing, and product integration requirements.
– Perform plumbing modifications before rebuilding shower floor to allow access from below.
– Have a helper to manage some of the awkward materials like shower pans and cement boards.
– Allow new shower mortar, thinsets, and grouts full cure times before using.
– Seal all concrete penetrations with waterproof caulking. Any breaches in waterproofing can cause leaks.
Conclusion
While a major remodeling undertaking, raising an existing shower floor is certainly doable for many DIY-ers. With proper planning and patience, you can save significantly versus the cost of hiring a professional. Just be sure to do thorough research before beginning demolition and take care to follow all building codes and installation instructions. A fully raised shower floor provides the opportunity to gain updated draining, fix leaks, improve safety and accessibility, and upgrade to beautiful new water-resistant finishes.