This is the part 3 in the series. Click here for Part 1 and Part 2.
Building the Shower Pan
Oately, Inc. has an excellent overview of shower pan construction here and my installation will be identical.
The curb for the shower pan is built using pressure treated 2 by 4′s and Tapcon concrete anchors.
Shower Curb Construction
The mortar bed for the pre-slope is being laid with a trowel.
Mortar Bed Pre-Slope for the Shower Pan
The pre-sloped mortar bed is completed in the photo below.
I spoke with several plumbing contractors and most said they skip the pre-slope mortar bed. Rather they install the PVC shower pan liner first and make the mortar bed all at once. If I were to do it over, I too would skip the pre-slope bed. The reason is the 40 mil PVC shower pan liner material is quite thick and needs the weight of the mortar bed to press it down so it will lay perfectly flat against the floor and walls; otherwise you’ll get “bubbles” and the shower floor will crack or groan when stepped upon. Fortunately, I had plenty of height in my shower curb as was able to lay a 1-1/2″ to 2″ thick mortar bed on top of the pre-slope bed and PVC liner. The shower drain is threaded and you adjust the height to meet the finished level of the mortar bed.
Mortar Bed Pre-Slope
The PVC shower pan liner is installed over the pre-slope mortar bed and about 8 inches up the shower walls. Take care to nail only the top edges of the liner to the walls to keep the shower pan waterproof. I’ve also installed 1/2 inch James Hardie HardiBacker cement board on the shower walls in preparation for laying tile using corrosion resistant screws. A hole will be cut through the PVC liner for the shower drain. For details see the Oatley shower pan instructions here.
40mil PVC Shower Pan Liner
Metal lath is laid over the PVC liner and tacked to the outside of the curb only so the mortar has something to grip. To make the 90 degree bends for the shower curb, I used a 2×4 and block to make a brake (a “brake” in this sense is device for bending metal). This worked very well with crisp perfect bends.
Bending Metal Lath for the Shower Curb
Another 1-1/2 to 2 inches of bedding mortar were troweled onto the shower pan floor with about 3/4 inch thick layer of mortar over the shower curb. The shower pan strainer is covered with blue masking tape to keep out dirt. The final result is in the photo below. Click on the image for a larger view.
Finished Shower Pan
In Part 4, the plans and materials for the porcelain tile are created.
Hope this helps.
Bob Jackson
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How many 2 x 4′s did you use for the shower lip?
The shower curb was built up with a total of four (4) pressure treated 2x4s. I chose this height for two reasons: It was a little more than the height of a floor tile for appearances and the shower drain is about 1″ inch or so above the cement subfloor.
Your shower curb could be as low as a single 2×4, it just depends on the drain level and appearances. Some showers are built without curbs.
I recently saw a demo of the Beno J. Gunlach Company “No. 455 Quick Curb(tm)” – a stay in place 4″ high shower curb form that you fill with mortar. Looks really nice and a labor saver!
Hi Bob- I appreciate the attention to detail that you took in describing and photographing the work you’ve done. It has been a valuable resource for me. I did have a question regarding your comment about skipping the pre-slope mortar bed next time you finish a shower pan. It seems to me that if you skipped this step, then condensation that filters through to the pan liner/membrane wouldn’t be encouraged to flow downhill towards the shower drain weepholes. I’m working on my first tile shower now and would love to skip the pre-slope mortar bed step, but I want to make sure that everything will still be water proof and drain well. Is there something I’m missing? Or perhaps you could explain more about why this step could be skipped. Thanks again!
I really wonder how much water gets past the tile, grout and mortar bed to make a difference. Not that the shower pan liner isn’t necessary or an excellent safeguard.
When I remodeled this bathroom, the mud bed under the tile was dry and there wasn’t a shower pan liner running up the walls.
What I would do differently is use a pre-slope system and shower curb form. Visit your local tile supply store to see demos of various vendor systems.
Do take care that your shower pan liner lays perfectly flat and snug against the pre-slope bed, corners and walls – trim, glue and use pre-formed corner tabs as needed.
Thanks for the help….one question…does the mortar bed rest up against the cement board? Or, would you say that the cement board sits on top of the mortar bed?
I mudded the pre-slope mortar bed first as shown in the projects photos. The purpose of the pre-slope is to establish the drainage grade.
The PVC shower pan liner is installed over the pre-slope mortar bed and run about 8 inches up the drywall for waterproofing. The cement board goes on the drywall, over the PVC liner (no nails here!) and down to the pre-slope bed.
The finish mortar bed is next and goes to the wall. Due to the slope of the mortar bed, you will have a small gap in sections between the level bottom of the cement board and the sloping mortar bed. I troweled mortar into these gaps to have a solid vertical surface for setting tile.
Post back if I haven’t fully answered your question.