Hi Kevin,
I see in episode 8 you'll talk about plaster for shower walls. I'm presently doing a bathroom/shower project totally in a lime plaster technique called tadelakt. It's a Morrocan plaster waterproofing technique. I've read about the application of it but that's all so far. I'd greatly appreciate any insights or advice from anyone who has worked with it.
Thanks,
Dave Mascoveta
Dave,
Tadelakt is a waterproof lime plaster originating from Morocco and, more specifically, from the city of Marrakech.
This plaster is made of a slightly hydraulic lime and a fine aggregate. Its application requires some very skilled workers and is very time consuming. The polishing of the plaster with a small stone provides wonderful results when executed at the right time, simultaneously with the application of black soap.
However, you have to be very careful: Any imperfection or cracking (due, for example, to settlement or movement) will lead to water infiltration and catastrophic damages. In order to limit these risks, the greatest care will have to be given to the construction of the shower stall and its primary waterproofing.
Good luck!
Michel Couvreux, President TransMineral USA
image sxc.hu, Fleur Suijten
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Tadelakt shower walls
I realize that the original post was from a while ago, but here are my thoughts, anyway.
Tadelakt is a great finish, but I would think very carefully about using it or another lime plaster for shower walls in a light wood framed house. In that situation, your primary waterproofing membrane must be absolutely perfect, from floor to shower-head height, just as good as the shower pan. This is nearly impossible to accomplish, especially if you are nailing or screwing metal lath into wood framing, through the membrane. The floor/wall joint will be especially hard to manage. Water will always get behind your primary finish (tadelakt or tile), and it must either drain away (into the shower pan and drain), or somehow dissipate. Unfortunately, a standard light-framed house won't do a great job of allowing the moisture to dissipate. Instead, any leaks will turn into dry-rot or wet-dry cycle structural movement, which will lead to more leaks, and so on. A masonry, concrete, or CMU structure would be much better for handling any moisture that does get past the finish. Tadelakt and the other natural lime finishes are great, but I would really think twice about using them for shower walls in most homes.
The other thing is that tadelakt is a luxury finish, and shower walls take a beating, from shower heads swinging on hoses, objects being dropped and bouncing off the walls, etc. Tadelakt is not as durable as tile. Is the owner prepared either to accept the natural wear and tear on the walls, or do the plasterer and owner have a clear understanding about the ongoing cost of maintaining a tadelakt surface in perfect condition? Consider using tile below the shower head, and using tadelakt everywhere else. Building green is great, but not at the expense of structural integrity and maintainability.
Having said all that, these would be a few of my tips (assuming that you already know something about the basic technique):
1) Make up some practice pieces. Not only does tadelakt require a good basic technique, but the results will vary depending on your individual approach. Given the setting times of scratch and brown coats, give yourself some time to do this.
2) Make sure that your second plaster coat is well-saturated before applying the tadelakt. If not, if not, it will be very hard to compress and polish the tadelakt. In addition, a well-soaked under-layer will allow you to apply a full wall or wall section before starting to rework and compress the finish. If you can't work the initial application quickly and in a large area, you will get something that looks like patchwork.
3) Make the second coat as level as possible. The tadelakt will exaggerate any flaws in the surface below.
4) Make yourself some proper tools for compressing and polishing. Epoxy a 4x4 piece of DalTile glass onto a wooden float, for a tool that can compress and polish larger areas. Epoxy wood handles onto smaller pieces of DalTile glass trim, for smaller areas. Yes, glass tiles are plenty hard for compressing and polishing tadelakt made with lime plaster and dolomite sand. Buy a quartz heart from a new-age crystal store, and epoxy a handle on to it for working on small, curved areas. I've been using those tools, because hunching over a wall with a little river stone in your hand may be authentic, but it is absurdly unproductive, and your hands will be crippled after doing one bathroom.
5) Except for initially spreading the finish, don't use a metal trowel, even stainless steel. It will stain the finish.
6) Experiment with colors. In particular, look at deeper and richer colors than you would otherwise consider; they bring out the beauty of tadelakt.
7) Set clear expectations with your customer about what they will be getting. Showing them your sample work is probably the best idea. Tadelakt can range from beautifully rustic to beautifully elegant, depending on intention, underlayment, applicator skill and experience, color choice, etc.
8) Definitely work up some sample pieces, to get yourself accustomed to the very different working properties of tadelakt. I see occasional mention of classes in the U.K. and Europe, but haven't seen anything about such classes in the U.S.
I hope this is helpful.
Firstly carpenter 2007 does
Firstly carpenter 2007 does not know what he is taking about. Tadelakt has been used for thousands of years in water applications. Tadelakt is so water tight you can have it on the inside of your bath. Tadelakt in the right hands will be water tight, no matter how much water you throw on it. Tadelakt application in the right hands, will not fail.
Never use a quartz heart from a new-age shop, always use a recommended stone and nothing else. Tadelakt once finished, and finished correctly requires no maintainence. Only those areas that get wet will have to be cleaned, and only if it needs cleaning, and only clean with white or black soap and cold clean water.
Before you install Tadelakt use a flexible waterproof tile adhesive and re-enforcing mess on all joints, this will absorb any movement/settlement of the structure. Use a lime cement as a base coat for your Tadelakt. Do not allow the Tadelakt to dry before applying soap. The soap needs the moisture in the Tadelakt to create a insoluble lime soap which repels water. Most importantly DO NOT get the Tadelakt wet during the first 30days. Tadelakt sets by carbination and takes approx 30 days.
tadelakt showers
Firstly carpenter 2007 does not know what he is taking about. Tadelakt has been used for thousands of years in water applications.
Excellent statement "expert" ..I think the discussion was about tadelakt use on a wood frame building,didn't realize they used wood framed buildings in morocco thousands of years ago,especially ones with plywood and vapor barriers,sounds to me like your mad at someone.
you make a bunch of broad statements with a mad tone of voice ,yet don't really explain yourself as to why...go figure.
If tadelakt does not need maintenance,except only the areas which get wet ,and the discussion was about tadelakt in showers (showers get wet).....the Tadelakt needs maintenance ...another stupid statement.
Myself I would rather see you outline your installation instructions backed up with some technical support as to the complete install details for tadelakt in a wood frame building,in wet areas in particular.
would be time far better spent ,rather then telling someone "he doesn't know what he is talking about"
respect
Anonymous and Anonymous, please keep the conversation respectful!
- maxmsf
Where to buy and follow Tadelakt workshops in the US
You will be able to follow Tadelakt Workshop in the US from 2008 on. Perfectino Tadelakt is a European Tadelakt manufacturer which is going to have a network of retailers and distributors in the US.
You can get all info on www.perfectino.com
I have recently imported a
I have recently imported a container of tadelakt from marrakech. I work with MTM, Marbella Mosaics and Tadelakt. A company in Marrakech. I trained with them and now apply tadelakt here in the states. If anyone is interested in purchasing tadelakt, I have it for sale in either 25 kg bags, a bit messy. Or i split it into 12.5 kg buckets. If you are interested, please email me at barefootdesign@mac.com.
Good luck?
Mildew on Hydraulic Lime in Shower
Our hydraulic lime plaster shower walls have been in use daily for 8 months and there is some mildew appearing at the lower part of one wall. What's recommended for cleaning this?
Thanks
JCW
Mildew on Hydraulic Lime
Hello, Have you tried waterglass (potassium silicate or sodium silicate) on your shower walls? I used Stone Technologies, Inc 's "Concrete Sealer X-2", which is that stuff, to seal some grouted tile over old concrete. It worked great. Silica is a big part of what glass is made of - thus the name 'waterglass' because it's in liquid form. RadonSeal is another brand name of sodium silicate here in USA. Lime is just CaCO3 that has been heated to drive off the CO2, then it becomes CaO, then mason's lime gets partially hydrated to Ca(OH)2 I believe, and then when it goes on the walls in plaster format it eventually reverts back to CaCO3 by taking CO2 out of the air and travels into the wet plaster on wall as long as it is somewhat moist. Hydraulic limes have some silica contaminant in them, and that's what makes them harden faster and stronger. When you brush waterglass on the concrete or hardened lime plaster, it soaks through the pores, and free calcium (Ca) already in the concrete or hydraulic lime binds with the liquid silica (Si) coming with what you just painted on. The silica fills up all the little holes in the hardened plaster or porous concrete, thus making it not porous and at same time making it waterproof. Waterglass colored with tints has been a traditional paint over lime plasters for many years, from what I understand. Zeim North America, Eco-House Silazur, Ecozmo, Silacote USA and Edison Coatings Everkote 300 are all some waterglass paint purveyors, while Zaclon, PQ Corporation, Silacote USA, and maybe Oxy Occidental Petroleum Corporation, also WinterSun Chemical are some chemical companies that manufacture the silicate solutions. A special silicate enhanced concrete was used in building the fish hatcheries near the Fort Peck Dam, and an award winning pozollan additive called VCAS by Vitro Minerals is basically just pure micron size particles of silica that come from recycled fiberglass maybe? I believe that is probably what Ecoprocote is using in their special Deco-Poz Resurfacing System (at Eco Safety Products). An article called Pozzolans for Lime Mortars at Building Conservation site is a nice read. You probably didn't want all that, but maybe it will help!
Cleaning Mildew in Lime Plaster Shower
This site has some good information about cleaning lime plasters: http://italianplastersplus.com/plastercleaningtips.html. One basic point is that lime plasters are not very washable.
What does your contractor/designer/architect say about this?
Lime Plaster Mildew
Thanks so much for this.I'll check it out. I came across your response by wild accident. I had no idea my email to the company would land up on a blog. I've never tallked to a blog before. So, I let the contractor and architect know about the mildew, with the implicit suggestion that I was looking for a solution. I also told them what the guy said who's fixing glitches in the American Clay walls, who's a clay/plaster whiz, namely to start minimally by drying it thoroughly with a hair dryer and spongeing it with 50% white vinegar, and if that doesn't do it move on to the big guns - bleach (with the risk of changing the color of course.). I haven't done that yet, and I haven't heard back from either the contractor or the architect.
P.S. It's a gorgeous, fairly experimental and expensive house.
Careful about cleaning natural lime plasters.
Ask your contractor an explicit and unambiguous uestion about this, and don't settle for anything less than a clear and unambiguous answer.
Not always a clear answer...
The real answer is that there is not a clear answer and one cannot predict the outcome of plastered shower walls...not even your builder/architect. If you have any question, or are looking for perfection, plaster is likely not the right finish for you. Deterioration will most likely taking place and one has to become accustom to this when using natural materials....Best not to stick it to you builder, because it is you that is making, or made, this decsion and have a choice to use something other than plaster... Be responsible!
As for clear answers....
I don't suggest that anyone stick it to a builder or architect. But building professionals should understand materials and techniques before selling them to the homeowner. In fact, even if the builder's just doing what the homeowner asks, it's _still_ the builder's responsibility to educate the homeowner about the choice, even if the builder needs to do some research. This should happen before the house is built, and not after. And if there are problems afterward, or even just questions, the builder should be stepping up to offer solutions or answers. That's just good business, having nothing to do with green/not green. And if the house is an expensive, custom, super-green project, then the builder and architect should be extra-prepared to answer plenty of questions, before and after the construction.
I think that this thread highlights an important issue for green builders and homeowners. Green materials and techniques are not all miracle cures for what ails the planet, because along with their many advantages, they also have some disadvantages, some of them significant. And although some of these materials have long and glorious histories, they are new to most builders, architects, and homeowners, who consider the expense, finishes and performance of "standard", non-green materials to be the norm.
Many, but not all, green-conscious homeowners will be willing to live with some of the imperfections. This should be the result of an informed choice, and in my opinion, builders and architects need to provide the education.
For what it's worth, I am firmly on the side of using green materials, and in particular natural lime plasters, when appropriate.
More about stains on plaster
1) Gentle scrubbing with water.
2) Gentle scrubbing with soap - black soap, Ivory, Murphy's Oil Soap at the most.
3) Try something solvent-based: try alcohol, acetone, etc. Not very green, of course.
4) Don't use bleach, anything citric, or anything acidic. These will destroy the plaster.
Beyond these choices (and probably just beyond 1 and 2), you should confer with your designer and contractor.
Thanks Carpenter2007 -
Thanks Carpenter2007 - you're on it. - maxmsf
Carpenter2007 makes some very good points!
Well said Carpenter2007. We have been applying tadelakt here in the UK and have had to come up with answers for all the points made by C2007.
We have trained with this finish in Marrakech and the average Moroccan bathroom is very different to a 'western' one, with substrate being a key point. Most Moroccan substrates are solid and concrete, which in itself forms a water resistant barrier. Many UK bathrooms are built using partition walls which use a wooden frame work, which are subject to movement and therefore cracking, with moisture absorbing plasterboard (sheet rock) and moisture absorbing gypsum skim plaster.
We have also found that the imported Moroccan product is a little crude. The fine, hair line cracks are difficult to sell / explain away and we are unhappy with the environmental impact of importing a heavy building product across continents.
We have spent a lot of time and effort overcoming these issues. We use complex and expensive membranes to form a flexible waterproof layer in shower cubicles and have sourced and excellent tadelakt product.
Tadelakt is a great product but substrates are crucial if a shower cubicle is to remain watertight!
more on tadelakt
I have been working with tadelakt for several years here in the US. I would agree that there are difficulties and issues applying tadelakt over wood frame construction, however, I think carpenter's statement is a bit dire.....
As with anything, there is a way to do it right. A shower over wood framing should be prepared exactly as you would for tile.. with backerboard and some type of continuous membrane. Over the waterproofed backerboard, we apply a scratched coat of fortified tile mortar. Then, a good 1/2" coat of lime/cement stucco. This thick base coat is crucial to have the proper absorbent base for the tadelakt. Tadelakt needs to be applied over a "thirsty" basecoat, this "suction" is controlled by the amount of water spritzed onto the wall prior to application. Traditionally, in morocco, tadelakt was applied to 2 foot thick rammed earth walls, earth provides a very slow, even absorbtion that allows the tadelakt to be finished quickly and easily.
As far as durability and maintenence.. I have done several showers that have been in daily use for over a year and they are doing just fine. No dings or damage from fallen objects, a quick wipe down with olive oil soap makes it look more beautiful than ever.
A great quality of tadelakt or any lime plaster is that it is breathable. Tadelakt is like gore tex. It stops liquid water but allows vapor to breathe out. So, if your tadelakt does leak, it is not the end of the world, it will slowly dry out and be good as new. You can tell if water has got through because you will have a dark spot that persists.
In modern building science we have a KEEP WATER OUT AT ALL COSTS ethos, this is a pretty tough way to live your life cause the water will always win.. So, better to use materials that can give and take moisture.
My own dream shower would be a freestanding 9" thick adobe block shower surround finished with tadelakt on the inside and raw unfinished adobes on the other side.
Tadelakt showers
I think carpenter 2007 has some valuable insightful point of view through experience.It is very important to hear the donts of installation as well as the postive hopeful practices of doing.
I would like to hear alot more about substrate preparation for finishes.This is the foundation,important as is a foundation for the completed house.I believe the substrate is a large percentage of the finish,the finish is the finese,the icing,a cake can have an attractive outer layer,but it's initial production and structure is the compliment to a fine outer layer.
I would like to hear more insightful thoughts on proceedure leading upto the final layers,this too I like to hear of others experience and techniques.
Thanks all for the good suggestions.
aka
Mudman
Tadelakt
Please have a look at our web site for more information on Tadelakt and a lot of pictures.