Mortar bed for a Swanstone shower pan

[Ross Hunt]

The instructions for the Swanstone 48 x 34 shower pan that I am installing, recommend pressing the pan into a 1/2 " thick bed of mortar. I tried that but ended up with the pan being high centered so that when you pressed on the outer edges it rocked a little. I think that this happened because there is a grid of supporting ridges under the pan that act as barriers and prevent the mortar from spreading out as much as I expected. So I have removed the pan and the 1st attempt at the concrete bed. One person suggested that I should not attempt to lay a mortar bed under the whole surface but rather only create a few lines of mortar that would provide the leveling and support function and allow space for the mortar to spread out. I want to get this next attempt right, so any tips would be appreciated.

[Fastclient]

I too am installing the Swanstone shower pan and was going to embed it in the recommended bed of "Quickrete" mortar mix. Since you posted this a while back and even tho no one replied to your question I assume you are done with the project. Any suggestions/tricks to getting it level in the bed of mortar?

[Gary Swart]

You don't need a solid bed of mortar. You should put mounds of mortar around the area so that when you put the base on them, they will spread out. You have to leave space for the mortar to spread out.

[Tobias]

I installed a neoangle last year on a mortar bed, solid like a rock. I didn't put mortar around the drain area, laid a circle around the middle and another circle with more mortar around the sides. This gives the mortar some space to move so you can level the shower tub. If it doesn't feel right the first time just lift the tub up and check for high or low spots, remove or add mortar as needed.

Tobias

[GregO]

I'm guessing your mortarbed wasn't screeded to 1/2" - it's easy to end up with "hilled" mortar unless you screed it - if you screed it to 1/2" evenly and use a slightly less stiff mix, it should work well. I know others promote the clumps, but personally, I prefer full coverage underneath to provide the best support. You could also use Terry's method of installing a thicker bed of mortar with the expectation that you will "seat" the pan base at a finished height slightly above subfloor level. Greg

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The instructions for the Swanstone 48 x 34 shower pan that I am installing, recommend pressing the pan into a 1/2 " thick bed of mortar. I tried that but ended up with the pan being high centered so that when you pressed on the outer edges it rocked a little. I think that this happened because there is a grid of supporting ridges under the pan that act as barriers and prevent the mortar from spreading out as much as I expected. So I have removed the pan and the 1st attempt at the concrete bed. One person suggested that I should not attempt to lay a mortar bed under the whole surface but rather only create a few lines of mortar that would provide the leveling and support function and allow space for the mortar to spread out. I want to get this next attempt right, so any tips would be appreciated.

[appleste]

I am sure that Ross has resolved his Swanstone installation, but to save any other unfortunate DIYers who may make the same mistake that he previously made and that I also made, here's what to do. First, Swanstone says that you are to make a 1/2" bed of mortar. I bet Ross, as I did, went to the hardware store and found a bag of Sakrete mortar-stucco mix. This was the only type of mortar I could find at Home Depot. It turns out that this is not the right material for setting a shower pan. Type S-mortar stucco mix has no strength and is made for skimming on walls. It sets really fast and has hardly any strength. I called both Sakrete and Quikrete and what needs to be used is something called "Sandmix". How would any DIYer know what this is. It is cement with sand. It has thousands of pounds of strength per sq. inch and is what you use. The term "mortar" is actually a rather generic term. Once I removed the mortar-stucco disaster from my concrete slab (actually not hard because it become dust), I mixed, on Sakrete's recommendation, half water-half Sakrete bonder additive to my Sandmix. It takes 6 hours to set up so you don't have to work fast. Since I was placing my pan on a concrete slab, I first wetted the slab, and then brushed on the bonding additive per Sakrete's recommendation. This sealed the floor. After letting that sit, I mixed up my Sandmix with the water-bonding solution and got it to the recommended 1/2". I put the pan in place, and then stood on the pan to set the pan. It is now rock solid and will never move. The only small mistake I made, but which did not at all affect the outcome, was I made the cement smooth. An architect friend told me later that it is best to use the teeth on you spreader so that the cement is ridged. This allows the cement to move around better. I hope this saves the next person from any problems.