How To’s for Advanced CAPS

Once thought of only as a feature in the home of a wheelchair user, curbless or “walk-in” showers are a hot item in new construction and remodels for people of all ages.   If the shower is large enough to dispense with a shower door altogether, that is even sexier.  These are an easy sell, and as the population ages more and more clients will be desiring larger showers.

A. Curbless Showers in an Existing Home

  1. Remove the floor decking under the existing tub or shower
  2. Carefully cut out the top three inches of floor joists within the  shower perimeter.
  3. This will weaken the floor joists a bit, so “scab on” one treated  pine 2”x8” brace just under each joist cut for reinforcement.   Before cutting take into consideration any exceptional load that may be supported by the joists.  Add a temporary wall   underneath the shower area if necessary.  Rarely is this      required.
  4. Lag bolt each brace into place with hot-dipped galvanized ¼” x  3” lag bolts.
  5. Re-plumb the drain so it is in the middle of the shower floor if needed.
  6. If the joist spacing is 24” or wider, consider adding some 2 X blocking between the joists for added strength
  7. Install ¾” pressure treated plywood on the notched out area after applying a generous bead of construction adhesive; nail or screw the plywood it to the joists.  This will serve as a sturdy platform for the  new shower floor.
  8. Apply a moisture barrier and pour the initial mortar floor, sloping it from the bathroom floor to the drain, leaving space for your pan and tile mud bed.
  9. Install your vinyl shower pan (or whatever waterproofing system you prefer) and tie it into your FHA drain; water test as required by local codes.
  10. Install mud bed sloped to drain followed by non-slip floor tile, 2×2” or smaller.
  11. Install a “water dam” just inside the shower on the sloped floor.  These are designed to provide access to a roll-in shower by wheelchair and rolling shower chairs users while containing water. A soft vinyl dam is flexible for wheelchairs to roll over and then returns to an upright position. It can be used in conjunction with a shower curtain to keep water in the shower area.  Vinyl dams fasten one of three ways:
    1. Some come with peel-and-stick high strength adhesive strips (I hope you have a short warranty);
    2. Some have a horizontal flange that goes under the finish tile, and
    3. Others are a clear vinyl flap that is held up by an anodized and polished, low aluminum threshold. (see photo from
  12. Installation of the latter requires a hack saw, measuring tape, and high quality silicone bathroom caulk, and stainless steel screws.  Securing the track with anchors is recommended.  These are available in 6-foot and 5-foot lengths. The dams can be white or clear, vinyl or rubber.  Costs range from $30. to $100.
  13. On the tile surfaces, there should be no change in level between the main floor and the start of the shower floor.
  14. Note that the proper slope for drainage is ¼” per 12”.  One handy way to assure the proper pitch is to use a slope grid like the Quick Pitch Shower floor drainage kit (Photo).  Cost is about $30. for a 3×4’ shower.
  15. A shower rod is the least expensive way to keep the water in a smaller shower, and it should be located 2-3” into the shower over the sloping floor.  If a shower dam is installed make sure the shower curtain hangs 2” inside   the dam, on the shower side

With Existing Slab on Grade Homes… 

METHOD 1: Demo some concrete

  1. After old tub or shower is removed exposing the old slab, lay out/mark the perimeter of the shower.-
  2. Saw-cut the perimeter, as close as you can get to the edge.
  3. Jackhammer 3” of concrete under the future shower floor. Since most slabs inside a home are 4” deep you may end up going through slab to the dirt underneath.  This is OK as it will make it easier to relocate and/or install the new FHA drain.
  4. ???? Once the drain line is in place, compact the soil and pour the initial mortar floor, sloped as mentioned above so the shower pan is on a sloped surface.
  5. Complete the shower following the steps above. shower carefully cut out the top three inches of floor joists within the shower perimeter

METHOD 2: Build up the floor

  1. If you have 6 feet of bath floor (or more) outside the wet area, you may be able to build up the bathroom floor so there is a high point at the entrance to the shower from which to start the shower floor slope.
  2. This requires the skill of a good tile setter to make it look right.
  3. Remove all of the existing flooring in the bath, down to subfloor or slab.
  4. Mark the entrance to the shower and set a 3’4” -1”” tall wood level marker (rip one out of scrap 2X lumber).
  5. Install your shower pan in the shower first, and make sure the pan membrane extends at least 32” outside the shower (check your local codes for this requirement).
  6. Gradually trowel concrete to create a gentle slope from the entry door and opposite side of the bathroom up to the level marker at the shower. Create a 4”-6” flat area at the marker board so the user doesn’t feel a “peak” or sudden change in angle there.
  7. Remember that you will be adding ¼” tile to this slope so measure accordingly.
  8. When you install the mud-bed inside the shower float the same way to the marker board.
  9. Remove the marker board and fill the void with concrete.

B. New Construction

  1. With a pier & beam design
    Same as A-1 above, but notch the floor joists before the subfloor is installed, or, the best practice is to possible build the entire floor joist system 3” lower under the shower inside its own 2×12” box frame.If the floor plan is well thought out, curbless showers in new construction are can be built larger (at least 5’ x 6’) than in many remodels.
  1. With Slab on grade
    Pour the slab with 3-4” recess where the shower floor will be located.