Finding the correct Hydrated Lime for limewashing brick fireplaces and walls can be very confusing and downright frustrating with so many products sharing “Hydrated Lime” name. Hydrated Lime for Gardening/Agriculture is not the same as Hydrated Lime Type S and neither are High Calcium Hydrated Lime, used for whitewashing bricks. Yes, they are all white powders, but they are completely different substances. Knowing the difference is vital for successfully whitewashing brick fireplaces and homes.
Finding High Calcium Hydrated Lime for whitewashing brick can be a frustrating endeavor, especially when the salespeople at the hardware store are untrained. I went through this recently at my local Ace. I bought high calcium hydrated lime there last year without trouble but when I went to pick up more, they had a completely different brand with labeling “For Agricultural Use” made by OldCastle Stone Pro
I tried to explain that ag lime was not the same as hydrated lime for masonry use but they kept on. It was the beginning of the COVID-19 epidemic so instead of risking infection further, I said “Fine, load it.” As soon as I got home, I mixed a sample with water and instantly knew it was not the same. For a great explanation of the different types of hydrated limes available, this is from the International Building Lime Symposium 2005 “Limewash: Compatible Coverings for Masonry and Stucco”
In many parts of the world, hydrated lime is made from limestone with a very high calcium content (95%+) and is known as high-calcium lime.
Uniquely in the United States, hydrated lime for building construction applications is made from dolomite (magnesium-containing limestone) and is slaked in pressure hydrators or by secondary steam processing that results in a lime of the very finest particle size. This lime is ready for immediate use and is so special that it is given an ASTM designation of Type S, Special Hydrated Lime. High-calcium hydrated lime in the U.S. may be designated as Type N, for Normal Hydrated Lime, and will require a soaking period of at least 24 hours in water prior to use.
Peter Mold & Richard Godbey
Dolomite Lime is not the same as High Calcium Hydrated Lime
Click on this link to see the differences in the types of Limes.
| Brand | Type | Chemical Makeup | Info |
| Greymont (also sold under Western Miracle brand name) | High-Calcium Hydrated Lime | Calcium hydroxide | SDS |
| Dolomitic Hydrated Lime Type S | Calcium magnesium hydroxide | Technical Info | |
| Chemstar (owned by Lhoist) | Type S | Technical Info | |
| Carmeuse | High Calcium Hydrated Lime | 85% Calcium hydroxide | SDS |
Jeremy G says
I’m still a bit confused. We’re interested in limewashing our brick fireplace surround & an interior brick wall. Can we use Type S hydrated lime to make the lime wash? or will that not work correctly? Thanks!
Genevieve says
Purchasing hydrated lime is very confusing. The US does not regulate what can be called hydrated lime, unlike in the EU where there are strict standards.
The only hydrated lime I can recommend is the High Calcium Hydrated Lime by Carmeuse which can be purchased from Limeworks or if you are lucky like me, from a local hardware store.
Karen says
Genevieve, I noticed the kind you recommended above is Type N. Everything I’m reading about limewashing brick mentions type S. Since you’ve used all the above products, do you know if both type S or N work for that? I’m confused about it. We’re having a hard time getting it here. I don’t want to waste money on the wrong stuff. Thanks for the help
Genevieve says
Buy the high calcium lime from Limeworks or see if your local hardware store (not big box) has Carmeuse High Calcium lime. You’re going to pull your hair out trying to find the right stuff from a different company. The bag has to explicitly say “high calcium”.
Save your time, money, and sanity by just ordering from Limeworks. (I have zero affiliation with them and don’t earn commissions through sales. They are the only consistent source of high calcium lime online.)
Karen says
Ok and thanks for your input!! My concern is you mentioned to someone else that type S is not pure white. We watched a YouTube video of a woman who used Type S hydrated lime from Lowe’s and she added a glass of brewed coffee and some water to her mix, nothing else. Hers came out a creamy white, which is the look we’re going for. Hoping we can do the same to the Type N and it will
come out kinda creamy off white. We don’t plan on using the other powder you added either. I was initially excited thinking about doing this project but it’s been difficult finding the line and researching it that it’s all overwhelming to me now. 😕 thanks again so much!
Genevieve says
For the love of…no. Just no. Coffee is not a lime stable colorant. Coffee isn’t even UV stable. It may have been “creamy” the day it cures but in a year it will not be that color at all. This is why I never publish a blog post until I’ve thoroughly tested the process for at least a year. Too many bloggers are throwing crap like this up without testing.
This is a link to colorants you can add to limewash: Lime Stable Pigments
Rebecca says
Hi, I’m not seeing the lime stable pigments link. Do you mind Re-sharing it? Thanks so much for sharing all your knowledge!
Genevieve says
Go to this page and scroll down to the bottom for the amount needed and links to the different types of pigments. https://www.earthpigments.com/limewash-recipes/
rajhlinux says
Good point. You should really point that out in this blog.
Stating simply don’t copy other bloggers without testing at least 1 year.
Also should mention your experience of knowing this.
Carol says
What will happen if I use garden lime and salt to make limewash?
Genevieve says
It wouldn’t carbonate thus will not adhere to your surface. Salt is unneeded and can be detrimental to the base surface, exposed pipes, and surrounding soil.
High calcium hydrated lime powder or lime putty + water is literally the only thing you need to properly lime wash porous surfaces.
Jerry McIntire says
Except that ordinary hydrated ag lime will carbonate. I’ve used it, and it stood up well for over six years. It’s true that salt is not needed.
Christina says
When preparing the Carmeuse high calcium hydrated lime for interior Limewash painting, how much lime and how much water do you recommend using? Do you let that sit with water on top for a specific amount of time before mixing with pigment and alum salt to make the actual paint to apply to the walls? Any tips or recipes are greatly appreciated!
Genevieve says
You do not need Alum to white wash. Only lime, water, and time.
I usually fill a 5 gallon bucket 3/4 full with lime powder then slowly add the cold water. This is the most dangerous part as it will create a cloud of lime dust. I make sure to be wearing all my safety gear and have a fan blowing away from me to keep the dust out of my face. I mix the water in and add more if there are dry bits of lime still. I let it settle for half an hour and if there’s lots of water on top, I add more lime. I make sure to have at least an inch of water on top once the lime settles and keep a lid on the buckets. 24 hours is best for full hydration but lime can be stored this way indefinitely and veteran lime washers say the longer you allow the lime putty to age, the better it is to work with. I just mix up a bunch of buckets as soon as I get my hydrated lime bags so it’s ready when I need it.
Kathryn says
Can you clarify, can the Graymont high calcium hydrated lime be used for limewashing? It seems to be all calcium hydroxide so would be similar to the Carmeuse product. I live in Canada and I can’t get the Carmeuse version.
Genevieve says
I don’t have experience with it but if you use it, please come back to update us so we can all learn.
Eva says
Is this the same as Mason line? I am wanting to whitewash the inside of our chicken coop, and am going crazy looking for the right hydrated lime in our area. I live in an agricultural area but everyone just has the garden stuff. TIA
Genevieve says
Yes, mason’s lime should work. If it’s a small enough coop, Pickling Lime works as well. It comes in a smaller package so you don’t have 50 lbs hanging around.
Just a heads up, lime wash on wood is not very durable. It has to be reapplied frequently as the movement in wood pops the hardened wash off.
Eva says
Thank you so much for the quick reply. I am having a very hard time finding Masons lime locally. Will try pickling. Thanks again!
Genevieve says
That’s why I ended up buying directly from Limeworks as I was spending more time and money on gas trying to find the correct stuff. Shipping is expensive but 50 lbs lasts forever when covered in water. Literally, forever.
Andrew says
Genevieve – Thanks for sharing everything… finding this stuff is more frustrating than I thought, even after reading this post!
Can you speak anything about coverage? How much does a 50 lb bag cover? I have a hearth and surround about 8’x6′ to wash. Think one bag will do?
Thanks in advance
Genevieve says
Oh for sure! A 50 lbs bag would nearly cover a 1500 sq ft house.
Emily Hesslen says
I’m so thankful I came upon your blog. This is the most helpful info I’ve found for DIY limewashing (found you via link shared by DirectColors). I’ve been dying to limewash our house, but I wanted to make the mixture myself to save hundreds of dollars (avoid having to buy Romabio or another name brand to get a tinted color). Your links to the Carmeusd lime and the Earth Pigments are what I will use. It has been very difficult to find good info. (I also came across the coffee tinted YouTube video and was considering giving it a shot out of desperation.) Thank you SO much for sharing your knowledge!
Teema says
Hello, and thanks for all the info. Would you please list 2 or 3 brands other than Charmeuse for brick whitewashing? I am having a hard time getting my hands on the “Charmeuse ” brand. Thank you!
Genevieve says
I can’t as they are the only manufacturer I know of in the US that has high calcium lime. If you can get your hands on buckets of lime putty, that would work as well.
rajhlinux says
Hello,
Might be off topic… which “lime” stuff to use to make “Tadelakt”? I’m so dead confused which lime product to make from scratch my own Tadelakt, I want to use Tadelakt so that I can make modern bathroom walk-in-showers. Tadelakt is waterproof.
Would you happen to know how to make a 100% waterproof limewash or lime product? Lime seem to be dirt cheap like cement, about $4 / 50 LBs bags from home depot of “high calcium pelletized lime”. I could use cement to make shower walk-ins, but I will also need to use a special expensive sealants which needs to be reapplied every 5 years or so.
With Tadelakt, no sealant ever needs to be applied, so this seems more logical.
Thanks for any advice.
Isaac says
I found Tadelakt from this site that I ordered high calcium lime wash from. They are family owned, you can call and talk to the members who are incredibly insghtful.
https://lancasterlimeworks.com/product/tadelakt/
Sarah Ruiz says
Hi Gen, what about lime washing concrete? I’ve read here about brick n wood, but sadly, nothing about concrete!?
For concrete, do I absolutely need salt n if so, can use any salt(i.e. Epsom salt[mag. sulfate] or Kosher salt[pure NaCl] or etc…), instead of the un-findable Alum salt(aluminum sulfate)?
Thanks a bunch, I’ll await your reply.
Regards; SR
Genevieve says
No salt needed. You only need hydrated lime and water.
I have lime washed concrete before and it the exact same process as bricks. Just don’t lime wash driveways or sidewalks as the glare is terrible. Looks good from afar but it hurts your eyes without sunglasses on.
Sarah Ruiz says
OK, thanks for your response.
Gen, would you recommend white Portland cement, with the lime, to obtain a thicker, opaque coating and ‘smashing white’ effect?
Sarah Ruiz says
Oh ya, i forgot!? Please remember that concrete is quite simply reinforced cement(w/ aggregates n re-bar/steel) n I am seeing, in ur pictures, that the cement between the bricks becomes quite white…
Anyhoo, please simply give me ur best recommendations, OK?
Kristin Comer says
Thanks for sharing, as others I was also having a hard time with what type to get. I want a full coverage no brick showing and I read on another post (don’t know if it was correct information) but she mixed 1:1 ratio. One cup of lime to one cup of water. Is that something I should do, to get full coverage on exterior red brick?
Genevieve says
No. You will get full coverage with multiple coats. Do not mix 1:1 lime to water. It will be way too thick and will not properly adhere. I’ve experimented with this exact ratio and I hate myself for it.
I repeat. DO NOT TAKE SHORTCUTS WITH LIMEWASHING.
Kelci says
I went to buy from the link and it’s $85 for shipping. Do you have any other brands you recommend?
Genevieve says
Holcim hydrated lime worked really well for me recently.
The best way to get proper lime is to physically visit your local hardware store and ask for it. It comes in 50 lb bags and should be about $25. Bricklayers use it and it should be near Portland cement. If it’s in landscaping, you don’t want it. It’ll be too grey instead of bright white.
Anne Collins says
My husband and I did this 45 years ago. No type S at our store so it steeped for a day or two. We added some Portland cement for adhesion.
12 exterior walls with that house. Used wall paper brushes. Looked so much better white.
I naturally faded but buyers painted with real paint.
I intend to do this with my new house.
Don’t want to live in a bank. 😁
Genevieve says
Haha! Throwing shade at bank design. You’re so right too. Such a good analogy.
Mike S. says
I’m trying to make my own whitewash for my many fruit trees. I found that I need to use hydrated lime mixed with water and applied with a paint brush on the tree trunks. Would the 50 pound bag of QUIKRETE Hydrated Lime type S from Home Depot/Lowes work for this? If not, what would you recommend instead? I’m in northern VA and not really sure if this kind of hydrated lime will work. I’m trying to avoid high shipping costs if I can. In the past I’ve used latex paint and learned that the trees need to breathe and paint actually does not allow for that so looking for a cheap and effective alternative.
Genevieve says
For this application, yes any hydrated lime can be used since it will need to be reapplied anyway as the tree grows. While chatting with a neighbor about my limewashing adventures, he told me about his grandmother limewashing her trees every year.
Now, is it okay or practical to limewash trees to keep pests away? I don’t know and would need to do a deep research dive.
Sb says
For limewashing trees, use lime and water and horticultural oil OR copper sulfate. Apply up to the first branch point.