Understanding Lime NHL5 etc

I discovered lime (chaux blanc here in France) as a cheap way to paint my cellar and started looking into it's uses. I thought I understood, but TBH am totally confused by different terms used on different sites.

I used the lime which is described as NHL5, mixed it with water and applied it and it's been great for cellar walls. I don't know whether this is referred to as limewash or whitewash, but it seems to have worked. I applied after damping the cellar walls, and it seems to be setting to a fairly good finish, but taking a long time.

I applied some to some dry plaster (and dry cement) and it set almost immediately I think drying rather than setting. I have also mixed it thicker and used it as filler, and also mixed with sand where it seems to set harder, more like cement.

I would like to try some on some interior walls because I like the finish, so I've searched Youtube, and found lots of mentions of lime putty, and using it to make whitewash/limewash. I've also looked at an old method of mixing with tallow to make it waterproof.

Confusion arises, because some people seem to say that NHL 5 is granulated slaked lime, but when I mix it I am not getting any heat from the reaction. Everyone warns about the reaction being almost explosive, but I get no discernible heat at all. This makes me think that my understanding is totally wrong and I'm worried I'm using wrong materials/mix etc.

From looking at lime putty It seemed this was just premixing with water and then leaving to settle. It's been said that this mix will then keep (under water) indefinitely and can be used to make whitewash. But then elsewhere it says that the NHL means that it can set under water.

Anyone out there can put me straight? BTW also looking at pigments if anyone has any ideas.

Thanks

Lots of good questions here that I'd like to know too
hope someone with some knowledge speaks up

Hi David, et al,

Lime is a wonderful traditional and natural product with a vast array of applications, uses and types (as you are discovering.) If you don't have years of experience working with it, and/or studying its different vernacular forms through history, it can be rather confusing and daunting, especially when you have companies trying to sell things to you (which is agenda driven.) Or the many...let us say "they think they understand?" types on the "boob tube," videos. If a video is "free for the taking," and not part of an educational program backed by a school, nonprofit group, or collective, you can guarantee someone is either "clueless," or trying to sell you a product or service. Be very careful with the "YouTube," culture!

I only had time to try and glance at your post, but see you have different thoughts and questions (as did Jimmy.) I will get around to writing an article here at Permies on "Traditional Lime," but in the mean time, if you could "boil" your question down into:

1.

2.

3.

etc.

I can then more efficiently try to answer them and give you reference links where applicable.

Regards,

j.

Hi Jay C and thanks for all your help?


1. What's the difference between NHL 5 Lime and slaked lime.

2. Why am I not getting exothermic reaction with NHL5.

3. Can I make Lime Putty with NHL 5?

4. Do I need to make lime putty for limewash/whitewash (is there a difference), or can I just mix it neat and use after a short rest.

6. What mix should use for internal plaster/filler on a plastered wall?

7. Can I use limewash on internal plaster and get a finish that won't be dusty?

And on a totally different note - can I use NHL 5 lime to on soil that is too acidic?

Jay C. White Cloud wrote:Hi David, et al,

Lime is a wonderful traditional and natural product with a vast array of applications, uses and types (as you are discovering.) If you don't have years of experience working with it, and/or studying its different vernacular forms through history, it can be rather confusing and daunting, especially when you have companies trying to sell things to you (which is agenda driven.) Or the many...let us say "they think they understand?" types on the "boob tube," videos. If a video is "free for the taking," and not part of an educational program backed by a school, nonprofit group, or collective, you can guarantee someone is either "clueless," or trying to sell you a product or service. Be very careful with the "YouTube," culture!

I only had time to try and glance at your post, but see you have different thoughts and questions (as did Jimmy.) I will get around to writing an article here at Permies on "Traditional Lime," but in the mean time, if you could "boil" your question down into:

1.

2.

3.

etc.

I can then more efficiently try to answer them and give you reference links where applicable.

Regards,

j.

1. What's the difference between NHL 5 Lime and slaked lime.

NHL5 (like NHL2, NHL3.5 ) is made of naturally hydraulic limestone which can set up under water; and slaked limes (or more commonly called "hot limes or quicklime) need exposure to air to set up properly. Non-hydraulic limes (what you get from cooking; sea shell, and some limestones that aren't naturally hydraulic) need air to carbonate and set.

Non-hydraulic lime is basically ( >~ 95% ) composed of calcium hydroxide. Non-hydraulic lime is created by first heating sufficiently pure limestone (calcium carbonate) to between 954° and 1066°C, driving off carbon dioxide to produce quicklime (calcium oxide). This is achieved in a lime kiln or just a pit fire for primitive mixes. The quicklime is then slaked – thoroughly mixed with water to produce a liquid matrix (and your exothermic reaction so be careful!) —the lime putty—or with less water to produce dry powder—a hydrated lime(or calcium hydroxide).

2. Why am I not getting exothermic reaction with NHL5.

Because it is a hydraulic lime.

3. Can I make Lime Putty with NHL 5?

No, remember it is a naturally hydraulic lime, and can set up under water.

4. Do I need to make lime putty for limewash/whitewash (is there a difference), or can I just mix it neat and use after a short rest.

No you do not need to make lime putty, and with hydraulic limes there really isn't any resting per se.

6. What mix should use for internal plaster/filler on a plastered wall?

Lime putty (many types from homemade to "fancy-schmancy" stuff. Just a little research (or the end of this post) will give you more info than you probably wanted.

7. Can I use limewash on internal plaster and get a finish that won't be dusty?

Only if you are really good, and knowledgeable (or experiment) with your mixes. It can be done (kind'a) but you can also put a tung oil or flax oil coat over it as well to stop "dusting."

A

And on a totally different note - can I use NHL 5 lime to on soil that is too acidic?

NO! at least I would not recommend it. Let see what some other gardeners besides me would say?

Regards,

j

there is 100 times more in my files (and head) if you want more academic and esoteric stuff like lime cobb, tadelakt formulas, etc....

http://www.buildinglimesforum.org.uk/why-use-lime

https://ncptt.nps.gov/blog/durability-of-traditional-and-modified-limewashes/

http://www.realmilkpaint.com/powder.html

http://www.traditionallime.com/consult/index.html

http://www.buildinglimesforum.org.uk/why-use-lime

http://www.limepaint.com/

http://www.lime.org/index/

http://www.scotlime.org/en/materials-analysis/

http://www.naturalhydrauliclime.com/index.php?display=what_is_lime

http://limeworks.us/index.asp

Thanks very much for the clarification.

I'm experimenting with colours atm and got a nice colour adding rust. Any idea if this will be stable or deteriorate over time?


Do you apply the flax oil by adding to a mix, or by sealing afterwards. And will this not colour the finish?

Do you apply the flax oil by adding to a mix, or by sealing afterwards. And will this not colour the finish?

There are ways to do both with oil-before and after. Either will make the color slightly "richer" (or darker depending on your perspective.) I have perfect color pitch (kind'a like perfect pitch in music except for colors...so when I look into a "blue sky" I don't get to just see blue, but red, purple, yellow, etc.) Colors look way different to me as I can see tone and shade in them as well as the base color.

Your addition of rust (iron oxide) is a normal coloring pigment for many different finishes and is very UV stable in its own right. Glad to see you are experimenting. Many of the links I gave you (once you get through them) have info on pigments, or you can just "google" pigments for finishes and you will get a lot of info. Feel free to bring questions back here, and I will do my best to help.

I gave you a link to "the real milk paint company." The owner of the company (Dwayne Siever) is a friend of mine, and has some excellent videos on mixing oils into paints for exterior work that you should find helpful. He is one of the most helpful company owners out there I have met. Doesn't try to "sell stuff" just want to talk "pigments and traditional paints and finishes." From watching Dwayne's video and reading his web page, you may have more questions. He does not sell lime paint (yet) but the info he shares has cross over to your work.

http://www.realmilkpaint.com/videos.html

Thanks for links. Loads of info. Still a bit confused.

Couple of supplementaries if you don't mind.

1. Because people talk about 'whitewash' and lime paint almost interchangeably. Most information is about the whitewash as when made from lime putty, whereas I am making mine from NHL 5. Is it not the case that this will be a different chemical composition than the stuff made from lime putty?

2. If it's different which rules still apply. You already said you don't need to let it rest (in fact I discovered you cannot let it rest!). eg Do you still need to apply to damp surface?

3. Still not been able to find a standard mix for whitewash and NHL 5. Any idea's (understand they might not be rules dependent on surface)

4. Theres a lot of talk about crystals forming (which ) I don't seem to be getting? Should I or is it a time thing?

My experience. I mixed a small batch to use/test in my cellar. Maybe It was a little too thick about 1:1 volume with water. I applied that to -

1. Damp render- Took about a day to dry. Reasonable finish
2. Dry render - took less than an hour to dry. Quite a textured finish - quite like it actually.
3. Damp stone - took a few days to dry.
4. Dry stone - took about a day to dry.

Notice I put dry - it does seem to dry (rather than go off)!

I've also painted over old emulsion - and it dried very quickly. Covered really well though. Very textured think it's probably a bit thick, but the thin stuff seemed so translucent I added some more chaux blanc.

What mix would you recommend?

Hi Dave,

You are not feeling different than many. I know of folks that have been working with one type or another (and many sales folks) that still can't explain just the basic lime cycle, let alone pozzolanic reactions, crystallization, and variances. Many (like myself) still are learning new "tidbits" every time we look at like, experiment with it, or think about it. "It is an ancient alchemy of loveliness to build our structures, cover things with, and generally make life better."

1. Because people talk about 'whitewash' and lime paint almost interchangeably. Most information is about the whitewash as when made from lime putty, whereas I am making mine from NHL 5. Is it not the case that this will be a different chemical composition than the stuff made from lime putty?

Now the "teacher" in me can't stay silent...so forgive me...I can't help myself.

What do you think?

Look at what lime wash is made of...relook and study the "lime cycle" and break down the constituent agents into their "common chemical names." Then ask what are differences (if any) in the finished product (especially in a protected space after a few centuries.)

2. If it's different which rules still apply. You already said you don't need to let it rest (in fact I discovered you cannot let it rest!). eg Do you still need to apply to damp surface?

"Wetting" is always advisable in many water based (or activated) covering materials. In this case whether you are dealing with "hydraulic" lime wash or "quicklime" wash...wetting is a good practice (and essential in some formulations to work properly or well.)

3. Still not been able to find a standard mix for whitewash and NHL 5. Any idea's (understand they might not be rules dependent on surface)

You answered this, really, in the end of your question...it depends. Hydraulic lime wash on wetted stone...you probably are going to get decent results...on a log or timber frame barn or house...maybe not.

4. Theres a lot of talk about crystals forming (which ) I don't seem to be getting? Should I or is it a time thing?

Depends on what facet of crystallization you are speaking on in the lime cycle, or some other component of "adherence" and "bonding" modalities within a render, wash, plaster, mortar, etc. Read more and I am sure more will reveal itself to you...then you will have more questions.

My experience. I mixed a small batch to use/test in my cellar. Maybe It was a little too thick about 1:1 volume with water. I applied that to -

1. Damp render- Took about a day to dry. Reasonable finish
2. Dry render - took less than an hour to dry. Quite a textured finish - quite like it actually.
3. Damp stone - took a few days to dry.
4. Dry stone - took about a day to dry.

If you do not wet the surface to be finished...you may not get proper bonding and adherence, as well as, may see more "chalking" or "powdering" in due course.

Notice I put dry - it does seem to dry (rather than go off)!

It won't "go off" you are using NHL not a quick or hot lime.

I've also painted over old emulsion - and it dried very quickly. Covered really well though. Very textured think it's probably a bit thick, but the thin stuff seemed so translucent I added some more chaux blanc.

As long as you are painting over with another fashion of mineral paint..."good"...latex or something else...most likely very "bad."

Also remember to "wet" the surface (not soak) between coats. I use a misting bottle or adimizing bug sprayer.

What mix would you recommend?

depends....

Seems that lime putty and NHL5 are at similar stage of cycle, just one is dryed to store, but one is mixed with more water and stays under water. If this is the case, I can't understand why NHL5 can set under water. If you end up with Calcium Carbonate at the end of the day, why will it sometimes be dusty and not others?

Anyway done second coat and we really like the finish so far (rustic) is how I'd describe it. Mixed it a lot thinner this time, so didn't spray between coats (hadn't read your reply at the time). Can I not just correct this on last coat. I do want to 'seal' it anyway.

Hi Dave,

Great stuff going on with you...thanks for reporting your progress! Photos of it during the process and after would be grand.

Since you are putting on a last coat (and sealing later I assume with an natural oil) you are fine to just use a "wetting" with the last coat. You may not even need to use an oil sealer as this is a protected area and not got see any UV degradation or precipitation erosion of the surface.

Seems that lime putty and NHL5 are at similar stage of cycle, just one is dried to store, but one is mixed with more water and stays under water. If this is the case, I can't understand why NHL5 can set under water. If you end up with Calcium Carbonate at the end of the day, why will it sometimes be dusty and not others?

NHL 5 and "quicklimes" (which lime putty is made of) may be in similar stage in the lime cycle...but they are made from different types of Calcium Carbonate - CaCO3. One has the presence of "silicates" in sufficient quantity (NHL5) that allows it to set with just the addition of water, while the other types of lime (like from sea shells) is absent these silicates. The "going off" or "extreme exothermic reaction" of quicklime is because of its need to take up 100% of the Carbon Dioxid it lost in the thermal decomposition reaction, or calcination when it was made by firing it in a kiln (industrial or primitive-traditional.) NHL5 only needs about 50% of this to start recalcification (or less) and sets rapidly without the "going off." Both get stronger in time.

If we keep going like this, the chemistry is going to get "thicker" and we will start talking about my other favorite subject in this area...geopolymers.

Regards,

j

Geopolymers - sounds interesting??

After applying another coat - internally, I had some left over so did some experimenting outside. This was a very weak mix, pretty translucent when applied.

It had been raining so I didn't damp with spray or anything.

Shed is concrete breeze block. House is render (suspect it's Chaux blanc - sand - concrete mix) 1955 France.

Front of shed fairly protected was partially damp but pretty clean. Applied easily and dried in a couple of hours to a white colour not much dust on fingers when rubbed.
Side of shed - dirty and dark and damp - Applied easily and dried in a couple of hours to an off white colour (Because of dirt?) not much dust on fingers when rubbed.
Side of house - protected, and pretty dry and clean. Applied easily and dried in a couple of hours to a brilliant white colour but much dust on fingers when rubbed.
Opposite side of house - exposed to light and wind and rain. Applied easily and dried overnight (despite heavy rain) to a grey colour not much dust on fingers when rubbed.

The results on Concrete block seem consistent, but on the render (as far as a I can see the same material) I'm confused over the colour difference.

Hi Dave,

You are beginning to see the wonders of mineral and silicate paints. You are also learning the wonders of natural materials over things like OPC. Lime on concrete good...concrete on lime, very bad.

We are also delving into some "truths" that the paint industry has spent the last 150 "white washing" (if you don't mind the pun) to keep folks buying the "crap" they sell. Homemade paints of all types (or at least natural ones) are much better all the way around. Yes, you may have to reapply some of them more often (not all of them) but that is no real issue because of the general ease of using them. If more folks would get off the couch and from in front of the "boob tube," and start doing the things around them their Great Grand Parents did...the better off they and the world would be...

Glad to see you experimenting!

Regards,

j

P.S. Photos...more please

Any idea why it would be whiter but chalkier. Could it simply be because of dampness of surface?

Not wetting between coats and perhaps drying to quickly..."powder or dusty" surfaces come from that as well as poor mixing.

Just to clarify. I can understand the dustiness being because of drying to quick, but what about the colour. It was all the same mix. Will the currently slightly gray eventually turn white. It hasn't yet on any test patches.

So at the moment it seems the less dusty/chalky finish is also darker in colour. I can live with this, but am aiming for consistency and understanding.

Each mix type will have a certain "tonal quality," and this can shift even between different batches of lime mix (in your case NHL5) So it's not like a manufactured chemical paint that can be dialed in time after time with in very exacting tonal qualities. You will have to experiment with other "whitening" or "lighting" pigments suitable for lime. Make sense?

Regards,

j

Don't get the tonal quality. I'm a pretty colour blind kind of guy. I recognise the primaries but struggle beyond that, we have a laugh talking about colours when DIY shopping!

The point is though - two patches same mix applied to same surface, one damper than other. Damper surface less dusty but more grey. Dry surface dusty but white. ( and dries much quicker.)

Will the damper surface ever dry to same 'whiteness'?

I will struggle to get all surfaces exactly same 'dampness' before application, so don't want a stripy wall

Whitening pigments - need some of them my bedroom's turned out pretty dark and doesn't seem to be getting any whiter. Where do I get them. ATM missus is suggesting I Emulsion over it which I don't want to do.

ATM missus

explain and define?

Drying quick is not always (seldom) a good thing. Drying slowly is always much better, gives a better set, and more consistent color to the surface. As explained earlier, with this type of system there are some variations in tone and shade of the colors between one application and the next. Seldom are these extreme (or visible to most) and present a much deeper and natural look to the finish.

As for "white" other than applying a commercial mineral paint over everything to get "exacting sameness," you don't have much choice other than what you are doing. You can add a whiting pigment to the mix like a "white clay" or some other "white" mineral pigments like titanium...all depends on how "exact" you want it all to look and how much time and/or money you want/need to spend to make yourself happy with the affect.

Here is one to start with: http: earth pigments

Regards,

j

At the moment my wife