Top Layer Deck Mud and Curb Mortar

The good folks from the John Bridge Tile Forum told us we could mud the bottom of our Hardibacker in place using our top layer of deck mud. Other sites suggested it was fine to do this with Durrock but not Hardibacker. The John Bridge folks said a properly constructed shower would not have problems mudding the Hardibacker; we kept it 1/2" above the liner.

After double-checking the weep holes with a plastic cable tie, we attached the strainer half of the drain, set it to the correct height, and poured the plastic spacers around the weep holes to keep the deck mud from clogging them. We wrapped a piece of galvanized metal lath around the curb to prepare it for the mortar.


Melissa mixed the deck mud.


We used our homemade 2X4 floats and packed in the deck mud keeping our slope proper. After letting it dry for a few hours, Melissa mixed up the mortar for the curb. Our first attempt resulted in mortar crumbling off the curb because we didn't use enough water. So we scrapped it and mixed in more water. The second time seemed better. Melissa carefully shaped the curb and although not perfect, we should be ready to start tile work in a week or so.

Hanging The Hardibacker

We used Durock when we tiled our upstairs bathroom. I hated it because it was so difficult to cut. I swore I would use Hardibacker next. So we picked up 10 sheets of 1/2" Hardibacker and a couple boxes of the screws that are made for it. The dude at Lowes remarked, "Yeah, Hardibacker is so easy. You just score it and snap it like drywall." Boy was he wrong.

Melissa and I made a nice deep scoring line and proceeded to break our first piece...nothing. I got angry and draped it over a 2X4 on the ground. We tried to break it by stepping down onto it...Nothing. I wanted to determine the breaking strength of this stuff so we both essentially stomped on the damn piece until it broke. It broke nowhere near our score line. Instead it bent, dented, cracked, splintered, and flaked off all over the place, but not on our score line. It was at this point that I decided I hated Hardibacker, too.

I got out my concrete jigsaw blade and showed Melissa how to cut. I don't know how she did it, but she cut ten pieces over the course of two weekends. Of course, we couldn't use a single full sheet, all ten had to be cut.

Cutting it was one thing. Hanging it was another. The pieces that are within standing reach were not that big of a problem. I was able to get enough footing to put my weight into the drill enough to get the screws flush with the Hardibacker. However, for 50% of the pieces, I had to hang from a ladder. This is when I really started hating Hardibacker and whichever company made the philips-head screws I was using. How about some hex-head or square-head screws? Hello!? Why on earth anyone would make philips-head screws with tapered driver slots is beyond me. Each damn screw either stripped or failed to countersink itself (when driven from the ladder). I just couldn't get a way to push hard enough from the ladder.

As I cursed and invented new ways of screaming how frustrated I was, Melissa did some Googling and determined most people have the same problem. She came up with a suggestion to use galvanized roofing nails. This saved the day and I backed out most of my misplaced screws from the higher sections and used the roofing nails, which I was thrilled to already have.

Preparing For Hardibacker

When we demoed the shower, I noted there was no insulation on the outside wall. That must have been one cold tub/shower in the winter. We, of course, remembered to hang some insulation.

Afterwards, Melissa cut the 15# roofing felt to hang as our vapor barrier.


I had the ingenious idea I would kill two birds with one stone by hanging the roofing felt by attaching my furring strips over it. When I was about 90% done I heard Melissa holler from the study that I had messed up; my stupid technique ended up with wood on the wrong side of the vapor barrier. Dumb. So I had to rip out the roofing felt (to prevent a moisture sandwich) and staple it on top of my furring strips.


Speaking of furring strips. I'm so sick of making them. I deciding early on to use them because our framed shower was not plumb or square. I figured the furring strips would give me an opportunity to fix these problems by shimming out the flaws. Although I was able to fix some obvious problems, man, I sure spent a lot of time cutting and hanging the darn furring strips!