Lime Plaster on Strawbale Gone Wrong, And How I Fixed It
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- เผยแพร่เมื่อ 5 ธ.ค. 2020
- How do you fix lime plaster gone wrong? Early in the building of Dancing Rabbit Ecovillage, when strawbale building was a budding technology, people tried some experimental stuff. It was the early days of the natural building craze. But to be honest, people are often experimenting because not everyone that builds their first house has all the knowledge they need to do it right the first time. We all make mistakes, and the combining of earthen and lime plasters on strawbale exterior walls was one of those experiments that failed.
In this video I show you what happens when you put lime plaster on top of earthen, and how it can be repaired to make a long lasting wall surface. It's a late season lime plaster repair job.
#LimePlaster #NaturalBuilding #StrawbaleBuilding
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I'm attempting to garner as much knowledge as possible, and you've given me much food for thought. In my 40 + years as a carpenter, I've been a strong believer in avoiding dissimilar components/ aggregates. Lime is gaining more attention as I go forward. The slow drying time has been pointed out regularly.
Hardcore sustainable keepin it moist
Nice video. You're very methodical and explain things well. Thanks for sharing your knowledge
Very informative and interesting video. It was fun to see Banjo, too.
Thanks for shooting this video. Nice work on the prep for the restoration/repair. Its looking gooood😁✌🏽
Thanks! I finished up this wall section this year and I think it turned out good. I'll have it in a video before long.
This is very informative!
thanks learnt a lot of solid key knowledge from you all most important stuff!
Great!You know what you are doing!
Thanks!🙌
I love your videos like this!
Thanks for sharing
Love the Lime!
What a cool house. Hope a can live in a house like that someday :)
Om Ah Houm
Great piece!
I did a lot of reading on the Earthen plaster vs. Lime plaster debate for straw bale. One of the main motivations for using Earthen plaster was of course was the better moisture permeability, and is more natural material. The other motivation is that if you have Earthen walls on the inside of the house and lime plaster walls on the outside of the house, then there is a difference in permeability between the two, which is not desirable. Another motivation might be the cost of the lime.
Regardless, I totally agree that lime plaster should not be put over Earthen plaster. I think this is a bad idea.
You may be interested to know that I used a hybrid approach on my exterior walls, which is far as I know I'm the only one who has done this. My plaster was 25% lime/75% clay for the first layer. 50% lime/50% clay for the second layer and 75% lime/25% clay for the third finish layer.
Now, my walls are only 3 years old, but so far no signs of cracking and separation. The outer surface is acceptably hard and weather resistant. My main motivation was getting more equal moisture permeability and protection due to the extra clay content. My interior walls are 100% earthen plaster.
Yes, that difference in permeability is something to consider because condensation can build up in the wall if there is a difference. I'd heard though that the difference was not as bad between earthen interior and lime exterior as opposed to earthen interior and lime with _cement_ exterior. Both lime and earthen plaster allow the flow of moisture, or the breathing of the building. I suppose there could be minor difference between them. I guess if you read in a book that it can cause moisture problems then it could be true. When I removed a portion of my exterior lime wall to put in my mudroom, the straw underneath was like new. I didn't see any moisture issues and my house has lime exterior and earthen interior.
I'd love to hear an update on your plaster in a few years. I've heard of people doing that transition using proportions of lime and earthen. The problem is that mixing clay into lime pretty much disrupts the lime curing process and the strength that it would otherwise have if it were pure. You are likely just getting the strength of the clay and the uncured lime putty in the plaster. Some sources also say that you should go from stronger on the inside to softer on the outside, which means do the lime first and the earthen over it. If you're doing that I'd say why even bother with the lime, though. You use the lime for the durability of the exterior layer.
The idea at the time was largely that earthen plaster is more sustainable, affordable, and breathable, which were all desirable qualities. But it's also less durable, more susceptible to damage from horizontal rain, etc, so using lime plaster on top, which is slightly less sustainable and more expensive but more durable, would be a good compromise. Of course with time ppl have realized that this isn't a great idea
I would like to ask the opinion of those experienced her with lime and clay. I want to build a tomato shaped house with strawbales as the starting point. I can visualize building vertical regular walls on the inside with strawbales, and the bulging look of the tomato as it were on the outside. It seems this works be possible using cob to make the bulge shape and then lime plaster as the protective layer? What about a clay soil style render on the protective outer coat? Opinions and observations welcome.
@@LitoGeorge Why?????
@@rubygray7749 why are you asking why?
Sweet pup 🐶
think I would be inclined to cover with some sort of mesh where the bale ties have been compromised
That could help in making the application easier, but I don't think it would make a difference in the wall strength or integrity for what is needed.
My straw bale house near Moab, Utah is a couple of years old. My exterior walls have a clay slipcoat mashed in well, then a browncoat of earthen plaster a couple of inches thick, then natural hydraulic lime (from France, and yes it cost an arm and a leg-but it's not a large house). The only metal is around the windows.
I had read some warnings about putting lime over clay but this is a very forgiving hot desert climate. There are quite a few straw bale houses in the area and I think a number of them have earthen plaster under lime, although the number using NHL is probably minuscule. Interior walls are earthen plaster.
We'll see if the lime eventually falls off! But again, very forgiving climate.
One comment on your video: I for one did not want smooth flat walls. I like the undulations.
Hello, i’m a natural building expert in France. Do check regularly for hair cracking, whitewash it with any local lime. Over clay render i recommennd a binding mesh ( jute or stucco screen) and a softer lime, aerolic, aeriel ? Air curing ? (yikes, translation ?! The term is chaux aerienne )
@@TheEmbrio Hi there, from your comment I gather that it could be OK to have the outermost layer(s) be Lime Plaster with the inner layer being clay/cob, IF you provide some matrix between them, such as jute (burlap) or wire mesh, and use a softer lime--but going softer as you protect against the elements seems to mean your outer coat will wear away sooner.... any thoughts? Thanks from California.
hi there. please share your recipe. are you not using any clay at all?
Excellent, Sir would lime+sand plaster hold on to concrete roof top too?
If you have hydraulic lime it can hold up to exposure like that, but not non-hydraulic lime.
Using a mesh wire would help retain the loose strawbales, otherwise, it may separate later on.
It would help especially if it was well secured to the bales. I think the plaster is pretty well bound to the bales now though. I worked it in good.
@@HardcoreSustainable thanks for response! Please update on the progress. I appreciate natural building!!!
Very interesting I did not know you shouldn't lime plaster over cob due to different moisture rates as you say. I will be building a straw bale house in the future and I would of done lime on top of cob so thanks for the info. Where I live it is impossible to get lime putty, but what I can get the bags of dry hydrated lime have you used this and if yes would you mix the lime to a cream cheese consistency and then add straw to in fill and leave the straw out for the finishing lime plaster Thanks in advance.
Lime plastering on cob is really common, but that is when your wall is all cob and not just a thin layer of earthen plaster, which is more susceptible to expansion and contraction. The bags of S type lime are all we can get here too, unless you pay an arm and a leg for shipping.
@@HardcoreSustainable would you mix the dry hydrated lime to a creamy consistency add straw allow for the straw to soften up then use it to level the walls up? WHAT mixture would you use for the final finishing coat cant wait for the spring lol thanks
@@johntraynor8777 I would do as I've done here, which is mix aggregate of sand with lime putty (made with slaked hydrated lime) and mix that with the straw to fill in. Ideally you'd want to have the layer be thin enough that CO2 can reach all parts for the curing process. That the straw is permeable would help with this, but still you don't want it too thick. You could also just use the lime plaster mix with aggregate and putty, but it would have to be pretty thin and would take a while to fill in the gaps. You could also just fill in the gaps with loose straw and then plaster over that.
@@HardcoreSustainable cheers and thanks so much
Couple things, important rule with lime plaster is soft over hard, lime over earth plaster would be hard over soft, so likely to spall. on Permiability something simler, lower permiabilty first, higher permiability later, so that mositure does not get backedup within the strata, so again earth plasters more permaibel than lime especialy hydraulic lime, so this was also the wromng way around.
Good point. There's someone here who wants to do earthen on the bales and then do a mix layer of earthen and lime and then gradually transition to all lime exterior. I question whether this will work and your point argues against this being a good idea. The mixture could possibly help with the difference in expansion and contraction, but the mix of lime and earth will not have any chemical process binding it like the lime will, so I doubt it will affect the expansion and contraction difference much. I don't understand why people want to mix the two anyways, but they keep trying. It's such a big risk and I don't see any benefits.
So anyone building a straw bale house today should skip the earthen plaster use on the exterior and go straight to lime plaster then it seems. . 20+ years of knowledge comes in handy for us all to learn from.
I would definitely recommend lime plaster instead of earthen. You can do earthen exterior, but you have to build large overhangs to protect from the weather and expect to replaster pretty regularly. This is done annually in some parts of the world where earthen plaster is traditional.
Might a courser aggregate on the base coat control shrinkage and cracking better?
Do you mean if you actually wanted to do lime on top of earthen plaster?
Just subscribed! Can I use lime plaster instead of concrete on an underground dome home? Or is there lime concrete or something?
I heard roman concrete (lime based) gets stronger over time, which is what all those ancient buildings are made of.
heard
Lime plaster wouldn't be usable in place of concrete. I've heard the same thing about Roman concrete, but I don't know what kind of mixture they used.
How many sq ft is your house. Are there any earthbag homes in dancing rabbit. Is your house earth in plaster or lime plaster.
Hello, thank you for this very informative video.
May I ask how was the ratio of your lime plaster mix?
Thank you 🙏
You mixed sand, straw and lime right ?
I believe I used 2 parts sand to 1 part slaked lime. I added a little water to get the right consistency.
th-cam.com/video/Xrwwcx9ZAGE/w-d-xo.html
@David Seiffert here is a great video ..it's explains and shows the ratios for lime plaster ..My 1850s home is lime plastered as grandparents were Irish...I do love watching HS though as he is in USA
Thank you for concise and informative video. We are about to start plastering, but it’s December in TN. Now I’m concerned: is the cold weather bad for plaster to cure, or is it just inconvenience for the worker?
Yes, do not plaster if you expect any temps below freezing. And you need at least a week after applying the plaster for it to cure enough to leave it. If it's still wet and it freezes, ice crystals will form and expand the plaster and prevent curing. It will never be a strong plaster and will likely flake off. I'd definitely wait until spring unless it is inside in a heated place.
@@HardcoreSustainable thank you! Glad We came across your video!
@@halinamann9535 you can use hot lime in most conditions, if that is something you can get over there?
@@bccochrane1 we didn’t know that, that you. We already have the plaster bought, so will have to wait for warmer weather. But good to know for next possible jobs!
@@halinamann9535 All the best with it :)
Can you give me your receipe for the plaster
Would you contemplate using a Darby on that next coat?
I do have a follow up video to this one where I show the final steps for the finish plaster. I use a trowel and a sponge or float to finish so it leaves a rough surface.
Thanks for the knowledge. Can you please tell me the ratio of the plaster Lime : Sand : straw
I usually do a mixture of slaked lime to sand of 2:1. You can mix the straw in the base coat in what amount you want. I made a pretty straw heavy mix in the base coat for this project. The finish layers shouldn't even need straw, but you can add chopped straw. I wouldn't recommend it for the finish layer though. You can use other kinds of fiber. Some use a plastic but I'd never recommend that because it isn't natural and will end up as microfiber in the future.
@@HardcoreSustainable Thanks a lot, I would use rice bran or husk for the base layer
Can you put like plaster on basement cinderblocks that have been painted with drylok?
If there is a rough enough surface for the lime plaster to key into it will probably stick. The drylok would probably make it less likely to make a good bond with the cinder block. I can't vouch for how long it would hold up.
@@HardcoreSustainable The cinderblocks and mortar are not very smooth but the drylok on top of them is in a flat kinda sheen. I wonder if it will help with adhesion if I use quartz primer first on top of the drylok then use lime plaster! I wonder if I could just use rough Intonachino plaster instead!
One piece of wire, and you're worried about the security of the bale? You should have secured the bales beforehand. The lime has corroded the wire, which is another reason why earthen plaster was a very good idea in the first place.
Actually, it was rust from moisture that corroded the wire and rotted the bale. This is pretty obvious. The lime wasn't anywhere near the wire. The earthen plaster was covering the wire. Why would you possibly think the lime, that is on the outside of the wall on top of the earthen plaster and doesn't corrode metal, would corrode the wire? Earthen plaster under lime was a really bad idea.
@@HardcoreSustainable somehow iron (also galvanised!), either mesh or rods etc should never be used with lime or mixtures with high lime content, as the lime reacts with moisture in a very intensive way with the metal and will make it rot very quickly. That's why in conventional building with cement, for long-lasting surfaces you use only cement mixtures without lime if you want to build in iron parts for strengthening. Of course, in your case, the lime was far away from the wire, which nevertheless corroded due to moisture that was held by the clayplaster. When building with strawbales a good idea is to only take bales that are bound with synthetic cords, which are really super strong and will never have any moisture problems. We used the spare cords from the opened bales in our straw-clay house for sections where we needed to bind parts together for strengthening... But we also did the claypalster-lime mistake over 7 years ago and in some parts there are some cracks and obviously some minor separation has begun. I guess it will still last many years to come, but it finally may need some replastering, at least in some parts... By the way, where is part 2 video of this one, with the final render coats? All the best and thanks for your good videos!
@@alexandrospfaff3637 I posted a video on my Instagram and Facebook pages. I haven't made one for my youtube channel yet. Probably should give an update, but I was trying to get crossover.
You are right that the lime was nowhere near the bale wire, so couldn't have caused any corrosion. It was from moisture from the bond between the earthen and lime plaster being non existent, as was demonstrated in the video.
Lay in some wire or expanded masonry metal lath! Good greif!
That would be a lot of unnecessary work and materials. I'd only do metal lath along the bottom of the wall to keep out pests. You don't need wire or lath on the whole wall.
That was the recommendation years ago, but not so much anymore.
Lime plaster! Roman cement!
Do you have another video on this.
On lime plaster, or repairing plaster?
If you scratch that with acrylic base coats first,then your plaster it will bond better, guaranteed!
Acrylic?? You mean paint? No, this is natural building.
Mine are straw bale and cob then lime plaster
What kind of lime you using please. Slaked putty, hydraulic (NHL), hot lime, hydrated type S ? Complicated thing lime as I’ve been learning.
Check out this other related video I made that explains what I'm using. This is S type lime.
th-cam.com/video/13OmC6ehn04/w-d-xo.html&lc=UgzjakPrIT6uuddKMOV4AaABAg
What material is preferable for tying bales? Should I look for bales that use plastic instead of metal?
I think the plastic are better for holding up over time, but ideally you shouldn't have so much moisture in the wall that corrosion happens with the metal. I personally think the metal can make tighter bales, which can be better for building.
@@HardcoreSustainable Sweet, thanks!
@@HardcoreSustainable as to tighter bales. when I saw teh bales zoomed in I thought it was compressed too much . teh straw was flattened (which decreases U factor significantly).
As to lime over clay issue it is all about different rate of swelling and crystallization of lime and clay (well ....purist would say it is hard to talk about crystallization in case of clay).
So the only way to give it a try is to do it teh way @Douglas Smith did. but .... one need to take the dew point under consideration.
@@Rafikius Yes it is the differing expansion and contraction rates of the earthen plaster and lime plaster. Lime doesn't expand and contract nearly as much, but the under layer of earthen plaster does.
It's true that less compression means better insulation, but you also want to have the bales be durable and firm enough to stack and form a wall. It could be it was compressed too much if the straw was flattened.
I think it can be done, but not with just any clay and you would need to do a lot of testing to get compatible clay. Our local clay isn't compatible with lime.
@@HardcoreSustainable Yup. Sigi Koko managed that on a very thick walls.
as to bales: I Also often used Tom's Rijven Method CUT (cell under tension) where we cut the rope after placing the bale in its place.
Nowadays we only use strong spraying the clay into bales as deep as possible. But I remember the best option was to pour very loose clay onto the bale so as it could sink in (percolate)and let it dry in full sun for 2 days. the clay penetration depth was almost 10 cm. the bale was of course much heavier. but moisture was driven away almost perfectly.
TFS
If the wall is made of clay sand and straw and plaster with lime clay and sand still the plaster collapse (or crack) like this after some time? Please reply
I would not recommend mixing clay into lime plaster. It will prevent the chemical reaction from happening that is necessary for lime plaster to cure.
👍
Guess you had to replace all those loose boards in the soffit also? How is your wall repair holding up?
The wall is holding up great. It looks no different than the day I finished it. I do need to do some work on the soffit and fascia of the house.
@@HardcoreSustainable Thanks for sharing your effort on this repair. That was a bit of work.
Yes there was a lot of exposed lumber in the trim and soffit and did not envy whoever had to address that.
BTW, was interested in placement of the meter base. What was the reason for this?
If I could I would insist the electrical meter is mounted at the last pole where the electrical drop is made and not mounted on the side of the house. That makes no sense and I am not sure how that convention got started.
I think the real problem is that the straw bales have settled. Wouldn't be surprising.
In order for the bales to settle they would need to be detached from the plaster on both sides right? that seems unlikely, though the lime plaster did detach from the earth plaster. I assume that the bales are only supporting their own weight, because the building was described as a "timber frame". That frame is supporting the building, not the bales.
Did you replace just that wall or the entire house.
Just that section of wall for now. The west wall needs to be replaced as well though.
Does lime plaster crack a lot. How long has the plaster been on. Where building a Strawbale and want to do lime plaster. Can it be sprayed on. What are the pro and cons of plaster.
It shouldn't crack if it's been done properly. The plaster had been on for 20 years, but it had been separated from the bales for who knows how long, which led to moisture and critters getting in. There is a way to spray on lime plaster, but traditionally the based coats are harled on, so thrown on with a trowel of sorts. Plaster is good for strawbales because it breathes and it also can expand and contract with moisture levels. It's a natural material too. I wouldn't recommend earthen plaster exterior if you aren't in a dry region because it doesn't hold up in the weather. Many people do it at DR but they have to redo it every few years.
i realise this is a long time after your question, but I did a week long straw build workshop 15 years ago, and we discussed using a stucco sprayer with lime plaster. At that time the builder leading the build hadn't used one, and was skeptical about doing so. Several years later they reported that they had tried it and were recommending it. The plaster penetrated the surface of the bales just as well as manually troweling it and the application was much faster.
Is the lime bee friendly? I want to use this method to coat a honeybee skep. How would you advise me on that?
I would not be able to say. I don't know about lime's toxicity to honey bees. sorry.
@@HardcoreSustainable oh, googled it and read that dolomitic lime and lime sulfur does not harm bees. I wash thing to use it to to make hives exposed to the weather moisture resistant. Does breathing wall keep it dry inside your buildings? Again thank you so much in advance. I wish that I and my children grew up with this lost uncommon knowledge .
Maybe I am wrong, but after reading many articles and books, I thought they all said that the bales needed to be coated with clay slurry is that what you mean by earthen plaster?
I've never tried that, but I'd think that would have the same drawbacks as the earthen plaster, which is a mixture of clay slip, sand, and straw or some natural fiber, usually manure too.
From what i have seen online, it is common to start with an earthern clay "cob" slurry of a milkshake consistency, an earthen "cob" basecoat with a consistency similar to a cowpie, and finally a finish coat of earthen "cob" with color, 5 to 10% lime and up to 10% Portland cement as a protective finish coat.
Why no wire mesh?
Wire mesh isn't needed.
Забей на стену деревянную решётку гвозди на 120 мм и сверху шпатлёвка глиной
I’m sad that 23 years is “old.” These structures need to last for hundreds of years.
ONe that's properly built will. This one wasn't properly built in many ways. Ideally houses would last hundreds of years. A typical house these days isn't built to last longer than the mortgage.
Stucco wire over the bales.
Then plaster.
That's not needed at all.
3:57 what is the mix ratio ??? thanks in advance for the answer
I believe it was 2:1 Sand to lime putty, but i do add a bit of water for consistency. It's too stiff if it's just dry sand and lime putty.
@@HardcoreSustainable Thank you man for your kind answer ! So as I understood from the video, this mixture helps the wall to not crack in time (yes applied over hay) but talking about a situation where you apply it over a cobb house, lime on rough clay stickiness
@@sorin990 I don't know if I understand exactly what you are saying. This method of applying lime directly to the bales is better than trying to apply cob or earthen plaster first and lime on top.
@@HardcoreSustainable Sorry,maybe my english is not that good,I am not a native english speaker . I was wondering if this plaster goes well with EARTH walls (hope I explained myself correct )
@@sorin990 Lime plaster is used on earthen or cob walls in many parts of the world, like Great Britain. I think it works better that way because the earthen layer is a 3 foot wide wall, so there isn't as much shrinking and expansion that would not work well with the lime plaster.
So, what about lime plaster exterior and interior. So how many people live at dancing rabbit.
Lime plaster exterior and interior is good. Right now there are about 40 adults at Dancing Rabbit. and another 6-8 kids.
How much is she selling the house for.
Why not use a mesh??
Extra work and expense.
Lmao, it's funny because people figured out how to build thousands of years ago and many of those buildings still stand. Man today is having problems getting it right even with all the technology.
Or their bad houses aged away and the good lucky ones still stand :)
@@iknowyouwanttofly true, not counting of coarse, the whole cities that have been found, and uncovered.
Im a contractor in germany and it is easily possible to build for at least a couple hundred years. But the people dont want to pay for it.
There is less R value if bales have the straw ends sticking out !
Not sure what you mean. Maybe you mean if the bales are not on end like these ones. The wall should have a higher R value stacked the normal way because the bale wall is much thicker, meaning a lot more insulation. A typical two string bale would be about 4" wider than tall, so that's 4" more insulation. The straw ends shouldn't make much difference as long as there is plaster on both the interior and exterior. The point is to trap air in the bale.
Metal doesnt do well in lime. Poor choice of bale wire !
Sowing jute cords or staking perhaps with plastic
Why?.......seems like such a headache and why no framing.....makes no sense
No framing? Which part is a headache? Plastering? Building with strawbale? There is timberframing on the Timberframe.
And in general this is not how to do it.
Are you married? jk. I loved the video. Very relaxing voice. Would've loved to see more behind the scenes stuff. Pity your so far away; would love to learn how to do this type of home building repair.