I live in the southwestern corner of North Carolina, and thus far it has proved impossible to find a source of hydraulic lime within a 2 hour driving radius from our land. Neither Lowe's, Ace, nor Home Depot carry it in our region, nor do any of the smaller hardware or building supply stores. It is very expensive to order online and pay for shipping. Does anyone have suggestions for where I might be forgetting to look? My fiancé and I are hosting an earthen lime plaster workshop in the Fall and will need a sizable amount of lime. Thanks for your input!
"Barn lime" is just crushed limestone and it's not hydrated lime not hydraulic lime. It could be used as filler in some plasters, but not the binder.
I would suggest buying high calcium hydrated lime locally and buying a pallet of some pozzolanic agent as additive to make the hydrated lime hydraulic. This is what I'm going to do for my exterior plaster. The finer pozzolan, the less is needed, so for example UltraPozz could be added in a ratio of 20%.
What are you going to plaster?
I don’t want to hijack this thread and go off topic, but here I go…
Cristobal Cristo, I have a question about what you just said.
I’ve been plastering my house all summer, many thousands of pounds of clay plaster. It’s been a simple base-coat of 3 mason sand 1 bagged clay 1/2 straw. I did a test finish coat on a small wall, and wasn’t super happy with the results. I used 2.5 mason sand, 1 kaolin clay, and 1/4 very fine sifted straw.
The finish coat was still a bit dusty, with some aggregate falling off when brushed. I applied with a stiff steel trowel, and burnished with a stainless trowel when leather hard. My research online showed that mason sand doesn’t typically have enough fines in it to produce a super smooth creamy finish plaster, and the advice was to put limestone dust in the mix to make up for the lack of fines. I was unable to find this locally, as I do not live in a place where there is limestone. I was unaware that I could buy this at a place like tractor supply, where there are many of those in my area.
Am I correct in thinking that this is what I’m looking for? Adding “barn lime” to a clay plaster? The barn lime is simply limestone dust, and won’t set similar to a hydrated/hydraulic lime and can be mixed with clay?
I'm also plastering my CEB house right now. For bedrooms I decided to grind (I have a rock grinder) broken and crumbled pieces of the bricks, because they are the same material as the wall. I'm adding 5% of cement (as the stabilized bricks have) and 12.5% rice straw. The finish is also dusty and very rustic, but I'm going to apply creamy limewash. After reading your suggestion about the limestone filler, I'm going to use the barn lime for the limewash and apply it with the brush.
I was looking for powdered limestone myself and did not realize that Tractor Supply sells it.
I called all masonry supplies looking for it. Originally I wanted to use it for the home made mosaic grout and then I bought powdered marble online and mixed 1:1 with white cement and grout turned out perfect.
For the pantry I'm going to use high calcium lime plaster and for kitchen, bathroom and outside - lime plaster with UltraPozz pozzolan.
Why do you want hydraulic lime vs hydrated lime? Hydrated lime is “should be” readily available in the states, while hydraulic lime is almost always imported. I have used some from st. Astier from France. Not cheap and not easily available.
But type S hydrated lime is available at my local Home Depot. Quick Crete makes one, as does most of the other usual suspects.
Scott- I live in central NC and have been searching for simple mason's hydrated Type S lime to do a lath and plaster wall. I've spent hours calling every mason, building, drywall, concrete supplier in the region, and no one has, can get, or has even heard of Type S lime. I know it's so available all over the rest of the US. I have no idea why we're in a lime desert here. But it's near impossible! If anyone has any other ideas of where to look, i'd love to hear them! Thanks
Location: Sierra Nevada foothills, 350 m, USDA 8b, sunset zone 7