How to prepare a painted wall for clay plaster with DIY materials? DIY primer? Something else?

My dilemma -
I'm currently in a home that's pretty standard construction for the southwest USA. Wood frame, dry wall, and then I believe there is latex paint over this on the interior (wouldn't swear to it, but I think so).
While I would frankly love to build a new home from scratch, that's just not going to be in the cards, monetarily. So right now I have been looking at clay plastering, from homemade clay plaster made from local material.

I have read that the right kind of primer can be used over latex painted walls before clay plaster use, but my problem is that I cannot use any brands of primers. I have a rare disorder that causes me to react to a huge number of substances and chemicals (which is the reason I'm looking at clay plastering in the first place) and primers and paints tend to be in that category, with rare exception (one brand of milk paint seems to be ok, at least). I've got to make this myself, from as natural materials as I can find. If something has a processed preservative, even, it's likely I'll be unable to use it.

After a lot of searching, I did find a recipe for a DIY primer for clay plastering over drywall using 10 parts wheat paste, 1 part fine sand (such as mason’s sand), 1 part clay, but first, it's drywall as opposed to paint, obviously, and second, it involved wheat paste and I'm very allergic to wheat.

Any ideas for what to do in this case would be welcome! Sanding off the paint entirely - would that damage the drywall too badly? Any homemade primers that could be applied over the drywall, in that case? Would other starches - like potato or arrowroot starch - work to make a DIY primer instead of wheat paste, do you think? Lightly sand the paint and apply some other type of DIY primer? Any recipes anyone? Any other ideas?


I have almost no experience with building materials, painting, and such, but willing to learn - have to, at this point! How much work it takes, or how long it takes to do, doesn't matter to me. I just need to find something safe for me to be around (and my daughter as well - she has the same disorder). Could really use some advice from those who have more experience, even if it's just in what is needed for a primer to work for clay plaster. What does it need to do to the surface? Any natural primer materials that have worked for you?


Thanks in advance for any help here!

I have a rare disorder that causes me to react to a huge number of substances and chemicals (which is the reason I'm looking at clay plastering in the first place) and primers and paints tend to be in that category, with rare exception (one brand of milk paint seems to be ok, at least). I've got to make this myself, from as natural materials as I can find. If something has a processed preservative, even, it's likely I'll be unable to use it.

Hi Shauna, it's difficult to next to impossible to recommend products without a list of chemicals you do not react well to. With that info you could also determine what it is causing bad reactions in your current environment? There may be some natural chemicals you do not react well too? Paints it is usually the VOCs that come from pigments. Latex is basically a plastic synthetic sheet that can promote microbial (fungi and bacteria) on the surface and in the wall known to cause issues with the chemically sensitive. You should be able to peel it off like plastic sheets. It should be removed as in taking the drywall paper off too. that would make a nice gypsum scratch coat for lime or clay plaster. There may be other issues like the HVAC, dust etc, being blown around.

Before you waste too much time and money guessing, find out the exact nature of the problem and solution is by understanding the chemistry to avoid. Put a list out here of the chemicals you react to so we can better assist.

Hey Terry -
Listing chemicals may actually be a bit trickier than expected, but I'll do what I can. The problem lies with this ridiculous disorder (it's called a mast cell activation disorder). It's one where I can react to pretty much anything with an allergic reaction (even things that aren't even substances, like stress or temperature changes - it's really wacky). And what I react to can quite literally change between one day and the next - it's not a normal allergic reaction, so normal allergy rules and chemical sensitivity rules don't apply, unfortunately. :-/

So you can imagine what an impact that can have on finding safe materials to use. I would pick one product to use and then a few weeks later I start reacting to it and have to palm it off to someone else. It was so frequent, I rarely choose any pre-made products for anything, now, but instead make things myself. I suspect I may need to do this for preparing walls for clay plaster (which I'll be making myself too), so if anyone has DIY recipes for this sort of thing, it would be the most helpful.

I think it might be best first to give a few examples of what I can use, to get a feel for the care I need to take, perhaps?
These seem to work right now, to give an idea of what level of chemical avoidance I need to try for.
milk paint (purchased)- this is the first product I've used in a few years that actually seems to be not too bad, so far. At least for sections of the house I don't go into much.
organic beeswax
Some natural sap and resins from local plants
glass or ceramics (old tiles seem okay, for example)
clay - if dug out of the ground. I haven't tried purchased clay yet, but all clay plaster brands I've seen so far are no good. Plain purchased clay might be all right, however.
metal (if no coating on it)
some raw, unprocessed oils
animal fats, processed myself
potato starch, if made by myself from potatoes
saponin extracted at home from soapworts
Untreated wood (cannot be treated for termites, either, so can be problematic in my area)
organic, un-dyed natural fibers (rayon is no good, but cotton and linen are okay. Not sure on some fibers)
could probably have some natural oils infused with anti-bacterial or anti-fungal native plants, too.



So, as to what is a problem. My reactions seem to trend along certain lines, typically ones that involve a lot of man-made chemicals, but many natural chemicals are not a problem.
1. For 'bad' natural products: neem oil, anything from shea, any essential oils, anything edible based in the grass family (so grain based, or sugar cane, or bamboo). Hay bales and straw are no good because they can contain some of the edible grasses, although wild grasses, cattails, and reeds are just fine, bizarrely.
2. Anything with ammonia is no good (if it dissipates quickly, I might be able to get someone else to do it for me, possibly)
3. Sulfites, sulfates, or high-sulfur containing products are no good.
4. Almost anything that has an added chemical preservative won't work, although some slightly more natural preservatives seem fine (for example, unbleached salt is okay, metabisulfite is not).
5. Pretty much anything that has added man-made chemicals in it that might off gas. The chemicals often present with plastics, paper, paints, floor waxes, modern cleansers, adhesives, and sealants tend to be especially bad.



That's it in a crumbly, disorganized nutshell, essentially. I don't know if there are any products that I can use out there, to be honest, although if someone knew of a very, very unprocessed product, maybe that would do But like I said, I've been making a lot of my own things these days because I react to so much, so often, that the only way to ensure I don't have major health problems seems to be to make things myself and avoid the frequent 'new' allergic reaction to something (have to mostly avoid other buildings as well, for this. :-/).

So I'm more hoping that someone might have some ideas for what might be needed to prepare the wall that I can make myself.

thanks for the information on the latex paint - I did not know it would peel off, but I can do that, I think! Do you know, Terry, if clay plaster can go straight onto the dry wall or if I need to do a kind of primer prep for that, by any chance?

Thanks again for your help.

thanks for the information on the latex paint - I did not know it would peel off, but I can do that, I think! Do you know, Terry, if clay plaster can go straight onto the dry wall or if I need to do a kind of primer prep for that, by any chance?

Bill Bradbury is the expert on this but he has computer issues right now. I'm experimenting with this on the thread below you may get some ideas with his guidance on the limestrong product....I just added a sandy primer scratch coat to drywall. I think if you took off the latex, if that is what it is, and drywall paper you would not need sand primer. He then adds a mud-lime-sand 1:1:2 scratch coat before the limestrong. He said the most natural muds are Wespac, Murphy I forgot to mention in that thread. You could scratch any natural high perm coat it just needs to have a grit or rough surface for the brown/finish coats to hold on to. That is if it is not the grade of gypsum in your drywall that is the issue. Roma is an all natural mineral zero voc silica paint and primer (Biogrip medium) it needs no sand added. It can go direct to paint/drywall as is and what I will use. Keim is another to look at. These paints do not make latex more permeable and the wall more natural despite the claims, latex has to be removed.

Latex has a very low perm rating so another way to tell is wet and see if it soaks into the drywall, if not it's latex. Latex comes in alot of different grades and perm ratings so it's hard to tell. If in doubt remove it. That will help the wall to breath. Not all clay's are created equal. Sandy desert clays do not work well especially on drywall. Clay's that can bind well and store alot of moisture without cracking from too high expansion/shrinkage (like sodium bentonite) do best like calcium bentonite and kaolin mixes, although your climate zone has little of that. I touch on that in the thread too. If you have question ask.

https://permies.com/t/49723/natural-building/Natural-Home-Mainstream-Home-Cost

Good luck to you, quite a challenge. Perhaps the best advice I could offer would be to hire a chemist or building microbiologist to determine the exact chemical(s) in your indoor air. From that info zero in on the problem product and consult with your doctor. If you were my client that is what I would recommend before you waste alot of time and money and may not end up solving the issues. Really what is needed is a new home designed with the proper chems. A deep retrofit may cost more than that.

IMO all homes should built for the chemically sensitive. I think that term is a misnomer.

hey...

did you think about stapling something to the wall where the clay might stick to?

like reet mats, burlap etc?

blesses
tobias

Hello Shauna.
I came across this thread, and found it interesting as I also have MCAS and I am also looking for solutions for more natural wall surfaces in a traditional home build.
This was posted 9 years ago but was wondering what you ended up doing for your primer and final surface coating?
Wheat is also an allergen for me, so I can't use a wheat primer coat.
I can probably use a non toxic primer with sand added and air the room out for a while.
In the past I have used "American Clay" wall covering, in another house.

I have found some very nice natural clay back in our woods and was hoping to maybe use it on my walls. I am wondering if I should mix in some lime for strength etc.
When I was looking for natural solutions for wall coverings, I came across someone using clay, toilet paper etc.
Has anyone here used a mix of natural clay, lime, toilet paper, sand and or hay fibers?

The walls I am working on right now, are painted wood paneling, with sheet rock underneath.
I was going to buy some lime products from a company, but it is quite expensive, so I am looking in to other options.
My goal is to leave the paneling there, but will fill in the groves. I would love to end up with a wall that has texture like old lime/clayish finish, with a little more depth that just a lime wash.
If anyone here has some ideas I would love to hear from you.
Thank you.
Pia.

I can tell you what not to try to put clay on.
Dry wall plaster.
They put up dry wall and taped the seems and used the plaster over the tape. Sanded it smooth.
All the clay fell off where the plaster was.
I think because the surface was powdery. The clay stuck to the surface powder and it didn't hold well to what was underneath it.

Sooo maybe flax seed oil? It has been used as a paint base before.
I didn't say linseed oil because it has some solvents,... but has basically the same purpose.
That might make the clay stick.