Bathroom Tadelakt

Tadelakt is not a well-known term.  Simply put, it involves making lime plaster water repellent by working in olive soap.  It is an ancient Moroccan technique that is simply gorgeous within a certain aesthetic.  For more info, you can learn a lot from an internet search or image search.  Feel free to start with this link.

 For better or worse, I am not at the level of craftsmanship to create a showpiece: I am basically treating tadelakt as a substitute for conventional tile because it is a low carbon, natural material.  I wanted the walls to have some color and not all pigments are "lime safe", and I found Earth Pigments to be a great resource.

This shows the final layer of plaster, including the green pigment, being applied to the north wall, below the blocking for the cabinets.  This layer is a couple millimeters thick (about 3 credit cards), which made it much simpler to mix.  Instead of the mortar mixer, which takes an hour to clean, I could do it in a 5-gal bucket.

With such a simple wall, I was done applying the plaster by 10:30.
It took the rest of the day to apply the olive soap, although it was not a continuous process.

FYI, I bought my olive soap from Black Soaps.  The info that comes with the product describes it as a very versatile product, so although I only used 1/10 of the little tub I bought, I'll be able to use it to clean throughout the bath, kitchen, windows, silver items, copper pots, the barbecue, boats, etc.  They even say it makes a great pet soap!

I used a four-step process:

1. Brush on a 1:20 mix of olive soap mixed in hot water. Polish vigorously with a semi-precious smooth stone.  This step was pretty time consuming (about 2 hours) and actually involved some muscle.  Take frequent breaks to avoid repetitive stress injuries.  Unfortunately, I didn't allow myself enough time to find a proper stone.  This is probably why my tadelakt isn't as shiny as many of the photos I see.  That's not important to me, though: I took a local rounded river-rock stone that had one nearly flat side and polished that one side to be reasonably smooth with wet/dry sandpaper.  Pretty low-tech, but it worked.  I found that my plaster dried pretty quickly, so my polishing was more to burnish the surface of the plaster, rather than to smooth out the larger irregularities.  I was never expecting a shiny, flat surface like a marble counter top, but I'm happy with the slightly irregular, mottled texture.
2. Brush on a 1:15 mix.  I used an older 2" natural bristle brush that was somewhat frayed and not suitable to cutting in clean edges anymore.  This quality, coupled with a circular motion worked well to ensure that the soap penetrated the complete texture of the plaster, rather than just sitting on top of the high spots.  I did another light polishing with the stone, just to be sure there were no remaining high spots.  Each layer dries progressively slower than the last.  After the first coat, the the top of the wall was  ready for the next coat by the time I finished at the bottom.  The second coat dried a little more slowly, so I used a small plastic bag filled with flour to smooth out the wet spots of olive soap so it would dry consistently
3. I didn't have to wait long between coats 2 and three: enough time for a snack, stretch, and sit-down.  The third layer was a 1:12 mix and took more time to work in with the flour bag.
4. By the time the 4th coat came around (also 1:12), the olive soap was sitting on the surface quite a while.  I'd brush on a section around 3-4 square feet, then move on to the next section.  Then I'd backtrack and use the brush to lightly smooth out the olive soap and move on to the third section.  Back tracking again, I'd smooth out the first section with the flour bag, and move on.  After the fourth section, the olive soap had mostly dried, but I'd do a final wipe-down with the flour bag to ensure there were no more wet spots.  Progressing in this way, I'd be working on 4 sections simultaneously.

After the walls were done, it was on to the floor using the same processes.  The only major differences were that this layer was about 3/8" thick (the max thickness for air to properly cure the lime), and I didn't add pigment.  Since this house is partly for demonstration purposes, I thought it would be nice to have some natural-color lime.

Note the extreme texture in the previous floor layer to ensure adequate grip for the finished layer.
I've taped the walls using a laser level to help get a level floor.

More than half done!  The left side, where the toilet goes, is level, and the shower drain on the right is depressed about 1".  I took the time on the previous two layers to depress them in order to keep the finished layer a uniform thickness.  

Done and treated with olive soap.  I used a sponge the next morning to get a rougher non-skid surface that is suitable for a shower.  There was some minor cracking, which I repaired over the next 24 hours by pressing down on the crack and smoothing out the lime.  That's one of the cool things about lime is that it is self-repairing for small imperfections  This process left the floor a little less uniformly smooth, but better to have a non-leaky floor!  

In the end, I can't expect perfection or professional results from myself since I've never done this before.  But after I take a step back, it's just fine and I end up with a special sense of accomplishment!