I have a Dreamline shower base to install. The installation manual does not say to drill screws in the base to the studs but I see a lot of people putting screws in. Should I just put the base in mortar only or put screws and mortar? I have a wood subfloor and I was going to put tar paper down on the subfloor before the mortar but I can only find large rolls. I only need about a 3x3 piece. Is there a cheaper substitute I can use like plastic or something? If not I will just buy a roll.

 

I would not drill into it. Every shower pan or tub I have installed has had clips that screw in above the flange. So I'm surprised this model doesn't have that. But after you level it in the sand mortar mix, I would probably just position a few galvanized roofing nails around the perimeter to hold it where you want it. The large head will act like a washer to hold it down. Just be very careful driving them and don't give them one whack too many. Shim behind the rim if needed so it has good support before you nail. You don't want to bust that lip. (You could also use truss head screws right above the lip, but again don't overtighten them.)

I think the mfg doesn't recommend any fasteners in order to account for expansion and contraction... (they recommend that 1/8" caulk joint) and also this way they are not responsible if you do fasten it and it cracks.

When you place the mortar, leave some voids here and there so the mortar has someplace to settle as you squish the base down into it. Don't put too much down or it will sit too high. If you don't have tar paper you can use plastic but I'd probably just skip it.

 

I'm a little confused. Why would you need to put a preformed shower base in concrete? When I did my 2nd floor remodel, we set the base directly over the wood floor to line up with the drain. The dealer we bought the base from never hinted at anything but directly on the floor. In fact, that is what he recommended.
In fact, the additional weight would be cause for alarm regardless of what floor it may be installed.

 

Standard installation practices for most tubs and bases are to set them in mortar or foam so that they have solid support. If yours was different it was the exception.

 

Any of those light weight fiberglass or acrylic shower bases need the support of the mortar bed, If not they will feel soft and flex, some can even crack over years of use.

Norm, wasn't your base some type of solid material? Those are different and don't require a mortar bed.

 

Yes, you're correct. I did not realize that we were speaking about the lightweight acrylic units. My base was so heavy we could hardly get up the stairway.

 

I installed a Dreamline base a few months ago (first time doing so) - Xsleeper's instructions are spot on. I was tempted to pre-drill the lip and put screws though it but ultimately decided that following the manufacturer's instructions was the best thing to do.

I put the mortar under it and it is nice and solid. I used tar paper but only because I had it left over from another project.