How to make cob and earth plaster waterproof.

21/4/2017

Frenk, Nicole, Noah, Tess and Me.

Last week, as luck would have it, I ran into a two natural builders tucked away in the hills of central Portugal. Lucky me; they showed me around their fabulous cob creations (not to mention plying me with vinho frisante and humous).

Take a look at this wonderful cob oven with cob seating area Frenk and Nicole built. It's gorgeous. But that's not the half of it. It's also water-resistant. The area containing the cob oven and seat isn't protected from the rain. Yet the cob has stood its ground.

How did they do it? They coated the entire thing in 3 layers of linseed oil. I'd heard about linseed oil from a few Mud friends in India where the stuff is cheap and easy to find, but I'd never tried it myself, because in Turkey the cost was prohibitive, more than organic olive oil!

The whole beautiful area.

"Yeah, it's not cheap here either," Frenk lamented to me, but good on him, he tried it anyway. "You heat the oil in a pan first, though not to boiling point. Otherwise the brush melts,” he explained.

Frenk and Nicole made their cob mixture out of clay, straw and sand. Initially, like me, they imported the clay. Then they realised the local earth was clay rich, and a glorious rust colour to boot.

The cob floor showing no signs of deterioration after a winter of rain.

Frenk is something of a rocket stove wizard, and has engineered another in his kitchen. If you want to look around it, check out the video. It’s very informative. The guy should have his own channel:)

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68 Comments

Daniela

22/4/2017 11:46:14 pm

Yes, it is usualy used to protect outdoor and exposed wood, my friend used it for raised garden beds, no heating, two layers and at least 24 hours between them so it dryes properly. It is a must, otherwise planks would desintegrate due to elements. It's miracle that it can be used basically on earth as well.

Chi

23/4/2017 12:03:34 am

Also, with linseed oil [aka: flax oil]: The organic flax oil used as food, is very costly.
But there are two kinds of linseed oil I have heard of, that are used for waterproofing cob, adobe, earthen floors.
1st kind has chemical preservative in it...avoid that.
2nd kind has no preservatives, but should be heated as described, to help it last longer without turning rancid.
Both kinds are sold in paint stores, or hardware stores. Might find the no-preservative kind in stores selling art supplies.
The tricky bit is figuring out which ones have the chemical preservative, and which don't.

Atulya

23/4/2017 04:18:15 pm

Hi Chi!
Yes, I did look in art stores in Turkey. It was even more expensive there. No idea why. Thanks for the information about the chemical preservatives issue. Should be more readily available in Europe, I'm guessing.

William

19/9/2017 09:05:12 pm

If your not concerned with organic you can recycle used motor oil to waterproof it.

Atulya

23/4/2017 04:15:04 pm

Thanks for that tip Daniela.

Chimonger

25/8/2021 03:19:51 am

Oh..yes, the cost is high for non-preserved, raw linseed/flax oil. That is because flax seed oil is fragile…that is, it turns rancid real easy.
The more easily an oil turns rancid, the more costly it’s likely to be.
Edible flax oils must be kept refrigerated, & not longer than a month or so after opening,
Coconut oil, on the other hand, has a very long room-temp shelf life, lasting many months before threat of rancidity.
But each type oil can do things others cannot. And, coconut oil was not available in Europe hundreds or thousands of years ago, so, heated flax was used.
Flax oil has ability to turn into a shell-like layer, sort of like a varnish, if it’s heated right…applied warm, it soaks in, & the chemistry that turns it into a hardened layer, starts.
Q.: Has anyone tried other oils for sealing earth floors & cob? I don’t know if coconut oil might do similar to flax oil, to coat cob. Or some other potable oil? Is there a difference between PUFA oils vs. nut oils—could that be the difference?

Dave

4/8/2022 11:17:27 pm

I have a silly question. I have just built a rocket oven and cobbed the base furnace all the way to the oven. Given linseed oil is flammable, could it catch fire as a sealant or do all the volatiles etc disappear once it’s used as a coating and dries? Just wondering if linseed oil on an oven adds an element of fire risk before I try it. Very excited about the idea though as the Cobb just melts away when rain hits it.

Wolf Jordan link

5/8/2022 03:13:11 pm

Linseed oil is not more 'flammable' than other vegetable oils, like olive oil, rapeseed oil, hemp oil, sunflower oil, etc.... Contrary to most vegetable oils, linseed oil is a 'natural drying oil', which means that this oil will take op Oxygen molecules from the air, connect this inside their molecular structure and in doing so it changes into a totally different product. Chemically spoken, this is a natural polymerisation (the molecules become longer).
After this drying process this linseed oil is not flammable either.
For a better penetration and for faster drying process, you can dilute this linseed oil (raw, boiled, standoil, etc.) with turpentine. The turpentine is flammable, so this mixture will become inflammable too. But once this turpentine has done its job, it partly participates in the drying process of the linseed oil and the rest will evaporate. Turpentine is a natural and vegetable product. You could also use orange terpenes or a mixture of both.
Some people use thinners made from petroleum, but they are too toxic in my opinion and they do not add any advantage to the linseed oil.
A dried linseed oil is, of course, not flammable.
Very high temperatures could destroy the dry linseed oil film, but if your oven gets that kind of high temperatures at the outside, then your oven design is definitely wrong.
The best way of protecting cob structures from rain, still is putting a good roof on top of it....

Dave

5/8/2022 03:21:03 pm

Thanks very much for the comprehensive and easy to understand response Wolf. Very much appreciated.

Erik Rowberg

6/8/2022 05:57:12 am

Agree with Wolf. put a roof over ovens. moisture will always be present and you dont want to seal that moisture inside, you want it to escape every time you use it.

Dave

6/8/2022 11:33:21 am

Maybe Erik, but when you’re in the open with nothing to attach a roof to, waterproofing is a good short term alternative worth exploring.

Atulya

7/8/2022 01:11:09 pm

Super thread here. Thank you so much Wolf for this brilliant explanation. You've answered some questions I had about turpentine too. When is your book out? :))

Jim Thompson

23/4/2017 02:20:46 am

Linseed oil - I've used in through the years on various wooden items.
For the application to cob are you using boiled linseed or or raw?
Normally we would use boiled linseed oil outside on fences, wooden house siding etc. and raw linseed oil elsewhere. The latter is seldom used around here (Mesa, Arizona USA) these days.
Thank you!

Atulya

23/4/2017 04:19:39 pm

For the cob as I understood it, Frenk used raw and then heated it (I'd heard about the boiled phenomenon, hence I asked him if he boiled it). So perhaps the heating isn't necessary at all? Hmm. Experiments are needed:)

ErikRowberg link

23/4/2017 02:31:35 pm

I have had good success water proofing masonry roofs by applying a clay-sand-lime plaster. then somewhat like tadelakt i press it repeatedly when it is leather hard. then several coats of lime wash. i imagine the moisture goes in some but even with repeated 8cm rains the mositure is not reaching the ceiling.

Atulya

23/4/2017 04:21:07 pm

Now you've answered another question. Good on you Erik! I wondered what would happen if there was lime in the mix. Apparently it still works fine. Very exciting and useful news. Think it would work for a pool?

ErikRowberg

24/4/2017 03:43:36 pm

I also dont think it would work for pool. roots would be destroying it. as i said i dont think my roofs are water proof, but very water resistant

Hans Quistorff

23/4/2017 11:54:16 pm

Think it would work for a pool?
Reply
Not likely. The linseed is making a water shedding surface not a water holding surface. Eventually the water will find entrance and begin softening the cob underneath. The clay itself of course is used to fill the pores in the dirt which resists the flow of water through it but the surface remains soft and open to failure when disturbed.

Atulya

24/4/2017 06:46:39 pm

Yeah, I thought it would end up seeping through. Really hard to find natural pool options. Clay also isn't enough when you're in a dry area and need to retain every drop you can get your hands on. The only answer is to live next to a river I guess;)

Cherokee

18/10/2019 09:30:49 pm

Ever think of a pool built like a cistern? So you enter through a door to minimize water loss...line the inside only with cement...not concrete but a fine, creamy layer of cement to make the inside of cistern/pool water proof....it was done similarly in petra...in Jordan

Chimonger

19/10/2019 02:00:38 am

I’d think slaked lime would work ok, as a water-holding layer inside a cistern, whether used only for cistern, or for pool. It swells up when wet, so should prevent much leakage; the swelling of it, from water, blocks water passing through it. Probly won’t prevent all leakage though. And, it won’t stop plant roots growing into it...,lime would be more as a coating, on, say, stone, block, or brick main containment.
Cement/concrete in various forms, has been used for thousands of years...maybe it could be the main containment, then slather on the slaked lime to help seal the cracks.
Tricky bit with cement, is that its nature is to crack..large and small; once cured, nothing but a good silicone water sealant or something like an EPDM barrier, will stop water trickling through the cracks of cement.
Maybe a slaked lime coating.
But, there are ways to decrease crackage in concrete....adding pozzolanic ash to the mix, helps cement be more fire and water-proof.
And, Using finer-mesh as part of the metal skeleton of the cement, helps.
(Use rebar tied into a 4” grid, then, tie on 1/2” metal mesh. Then apply the cement, working it completely into/through the metal structure, then scree off excess to finish the surfaces smooth, to just a bit thicker than the mesh.)

Chimonger

25/8/2021 03:30:38 am

Oh..forgot bit of info. Years ago, I tried an off-brand of glue as an additive to plastering mix. It had similar consistency to Elmers white glue, except it was a bit thicker. No VOCs. Name: WeldBond glue. It was a general-use glue.
Adding about 2 Tablespoons of WeldBond to a 5 gal.bucket mix of dirt, Portland, pozzolanic ash, & slaked lime for good measure, then added water to mix..then plastered the 1st layer onto the bales with it. That experiment never got a 2nd coat.
About 15+ years later, with total neglect, the weather-exposed plastered corners appear to still be in very good condition.

Dianne G

24/4/2017 11:35:24 am

Love this article and the tip for using raw linseed and heating it, I have used it to weather proof wood and other putty to glaze windows. Needless to say it has been imported from he U.K. In my baggage. As someone mentions above the boiled linseed oil you buy has chemical compound to make it go off quicker. The word boiled is totally misleading.
Would love to try and create a floor using cob and the oil. Another project!

Atulya

24/4/2017 06:48:14 pm

Yeah, there are some AMAZING cob floors. I can't imagine how nice they must be to walk on.

Greg Pappas link

25/4/2017 02:29:08 am

Very nice find. I've found in a number of natural building books the recommendation for using linseed oil for earthen floors, which require a new coating every few years to stay durable and fresh. The application to walls sounds like a possibility, dependent upon the area of the world.

I've been looking for a natural solution for plaster on my earthbag constructions in Honduras, and so far we've used a cement/lime mix simply because of the tremendous amount of rainfall and possibility of hurricanes (and rain often blowing sideways). The cost of the oil and maintenance schedule makes it prohibitive for my applications unfortunately.

Keep up the fantastic work Atulya and safe travels!

Atulya

25/4/2017 03:50:53 pm

Your school project is fantastic. Well done Greg! I know how challenging it can be when funds are limited and far from resources. Your project has heart and soul. That's the most important thing. Take care there!

Jehane link

9/5/2017 06:34:09 am

Have been plastering with paper Crete at least beginning layers final lime plaster thanks for tip on linseed oil for rocket stove on con LOVE AND SO FOLLOW YOU

ErikRowberg

1/5/2017 11:41:05 am

I would stay away from cement in plaster on earthbag. i also used cement in plasters in years back but have come to read and experience they can cuase other problems down the line. i have earth walls in direct exposure to rain.

Atulya

1/5/2017 01:30:54 pm

Yes I know. It tends to crack and fall off. Earth and concrete don't mix well at all because Potland cement holds onto moisture and isn't breathable. Lime is the way to go in wet climates. Trouble is It's not available everywhere.

ErikRowberg

5/5/2017 06:33:53 am

Greg, curious if rain is actually affecting your walls, even sideways wind. I have garden walls that go through 2 years of heavy rains. then get wet on the tops and dry in between. I see some two story cob houses that have only small deterioration after 15 years and only on one part of house. a tree right there would stop the driving rain.

Wolf Jordan link

25/4/2017 10:54:14 pm

Most vegetable oils will not dry. There are a few exceptions: linseed oil is one of them (toghether with tung oil and poppy oil)? This oil will take molecules from the air and change into a completely different product. This is why linseed oil is so extremely good. You can use raw linseed oil, but the process takes a very long time. Boiled linseed oil dries much faster and becomes better water resistent. You could do it yourself, but this is bloody risky, I can assure you! Vegetable oils are becoming very inflammable when heated and would you take the risk of your house burning down for just a few litres of boiled linseed oil? Our country (Flanders part of Belgium) has been famous for flax, linen and thus also for linseedoil and its technologies. We have excellent quality of linseed oils in different forms (raw, bleached, boiled, standoil etc.) for affordable prices. And 'preservatives' in linseed oil? No, this is not done. But there are siccatives available, those drying agents usually salts (uasually calcium, zirconium, zinc and/or iron) who will speed up the drying proces (they act like catalysts) but don't worry, they dissapear into the new chemical structure of the linseed oil. If you don't want to use this, just take raw linseed oil. If you heat it up just a little bit (please: be careful!) it becomes more fluid and will penetrate deeper into your cob (or wood, or stone or whatsoever).
If you want your cob to become stronger, then mix some ash from the woodfire (from the pot of the stove, the 'pot ash' because this contains potassium, hence the name) and linseed oil directly into your cob mixture.Especially good for strong floors.
btw: in Africa they waterproof their cob houses with shea butter.

Stephanie

10/10/2017 10:27:09 pm

Hi Wolf,
I want to protect some clay areas of my strawbale structure. All they have in my little town is boiled linseed oil so I got that. I have been told that it deteriorates from sunlight. Do you know this to be true? Also, how do you dispose of your brushes as the container says it can combust on rags?

Wolf Jordan link

11/10/2017 11:43:46 pm

If they got boiled linseed oil, well that's just perfect.
If you could also find turpentine, then you can dilute the boiled linseed oil with this turpentine oil (up to 50/50), which will give better penetration.
The sun will slowly deteriorate the superficial layer, that is correct, but this proces will take quiet some time. That is why diluting the oil will make it penetrate deeper into the cob and there, don't worry, the sun will not penetrate into your cob... Re-doing depends upon the surface, the weather, etc., it can take from a couple of years up to 10 or 12 years.
All vegetable oils are inflammable under certain conditions. The spontaneaous combustion is only possible when rags, impregnated with oil, are left in a rubble. If you dry them flat out, there will be no problem. Don't worry about your brushes, they will not explode... But once dried, you cannot use the brushes anymore, they will become hard. So clean them (with turpentine) and wash them (with soap and water) so you can re-use them.

Stephanie

12/10/2017 05:49:07 pm

Thank you Wolf!!!! Very helpful and straightforward!

Atulya

12/10/2017 09:18:24 pm

Yes, thank you Wolf for your generous sharing of your wisdom.

Arlene Saunders

4/5/2020 03:35:16 pm

Hello Wolf - If you could answer this for us. We have built a cob oven - and will final treat it with the boiled linseed oil as described (we do have it under an open walled structure as well)... I would like to do the first coat 50/50 mix with turpentine to ensure the mixture penetrates effectively.. but am unsure about this as it is an oven - High temps.. should we just stick with the Boiled Linseed Oil? Safest bet?
Thanks for your help!~ Writing from Ontario Canada

WinterStar

9/7/2020 05:22:36 am

How is non-boiled linseed oil, or Shea butter, into cob, not turning rancid?
Heating/ simmering a vegetable oil, denatures the food value of the oil, helping it to remain stable, instead of turning rancid...which makes it toxic.
Using a raw food oil in a long-term application like a house, begets a rancid house, sooner than later. And maybe attracts pests. You don’t want to make your house attractive to pests!

Wolf Jordan link

9/7/2020 05:48:59 pm

Hi WinterStar.
As I explained earlier in this (interesting!) thread:
Yes, most vegetavble oils will get rancid.
BUT: there are a few exceptions.
Some natural vegetable oils are "natural drying oils", which means that the fatty molecules will take oxygen molecules from the air into their chemical structure. This way, they change fysically and become a totally other product.
Chemically spoken, this is a completely natural proces of polymerisation.
Those drying oils are linseed oil, tung oil (sometimes also called chinese wood oil) and poppy oil.
Some oils are partly drying or semi drying, like rapeseed oil. Which is the reason why in earlier times this was used to lubricate for instance the axes of train wagons. The drying part of the oil sticks very well to the iron while the none drying part can lubricate in a way that the axles never ran dry.
Back to the linseed oil: because this forms a solid, flexible, breathable and long lasting film, our ancestors have developed the know-how to make excellent linseed oil based paints. First to treat wood (you can imagine: both are plants, or plant related, so there are family) because the very fine unsaturated fat acids are super fine, so they can penetrate deep into the wood structure (wood consists of small chanals) an nourish them. Then they will polymerize, meaning change their chemical structure, and the adhesion afterwards is incomparable to the modern paints, where petroleum derivated oils are transformed into 'polymers' and then used as binders in paints. Those synthetic paints have already long molecular chains (hence the name poly-mers) when applied. This gives a much poorer adherance. Many of those 'plastic' layers can easily be be removed. Not the natural oil based paints: they go deep into the surface.
About the sea butter: I do not know if this is also a naturally drying oil. I only read that in some African countries, where the locals build wonderful, organic and colourfull houses and dwellings from earth and mud, that those people apply shea butter to protect their buildings from rain.

Atulya

16/7/2020 01:25:25 pm

Thank you so much Wolf. Let me know when that book of yours is published:) There isn't much you don't know about natural oils and lime.

Chimonger

25/8/2021 03:38:37 am

Wolf Jordan, thank you for such great information!

Atulya link

26/4/2017 02:04:30 pm

Whoa! So here's someone who really knows their oil. 😁 Thank you so very much for taking the time to offer this expert information Wolf. It's incredibly useful.

Frances

30/4/2017 09:43:28 am

In Mexico they waterproof their adobe, cob or mud houses with cactus slime.

Atulya

30/4/2017 11:26:54 pm

Yes I heard about that too. Wonder if Turkish cacti would have worked
The for reminding me of it.

Wortex

4/5/2017 10:42:56 am

I know that this goes much against natural building principles but ... as we should also seek for ways to help industrial waste stay off from landfills, it kind of make sense. Any way. What if one used used motor oil to seal the cob? Would it work and would it be stable? I mean, has anyone tried it? Mud should bond with the oil so rain cannot wash it off to ground so it wont reach the groundwater right? So if it would work as a sealer for cob as well, it could be cheap option? Or what do you think?

Wolf Jordan link

4/5/2017 06:29:26 pm

Motor oil is a petrochemical product. Certainly when used, it will be full of really toxic elements. You get chemicals that evaporate as well as chemicals that will soak into the cob and into the earth as well.
Motor oil is not a drying oil, don't forget that.
So, in my opinion, an absolutely irresponsable and bad idea.

Chi

4/5/2017 08:05:21 pm

Absolutely agree: motor oil, and other kinds of petrochemical-based oils and substances, = very bad idea on Cob, adobe, or straw.
What's the point of making a non-toxic, earth-based building, then pollute that with petrochemicals? [bad air quality forever; toxic to living things]
One solution is to have 4' to 8' deep overhangs all around, and keep the building to single-story height...then it's not necessary to waterproof lime plaster on Cob or bales.
OTH...if you want something durable and waterproof, and don't mind some petrochemicals, maybe Cob is not what you want.....maybe Earth-filled tires would suit your purposes better? Those also get plastered [which blocks their VOC's from outgassing into living spaces], but can be plastered using stucco or cement.
Adding a glue like WeldBond [only takes a little] to the plastering material, can help make it far more wear resistant and strong.
I think my experiment used about 1/4 c. of WeldBond glue, per approx. 5-gallon bucket mix of: about a shovelful of Pozzolan + about a shovelful of portland cement, + a few shovelfuls of dirt from the site to fill the bucket, mixed to consistency with water.
I worked that into an exposed corner of a strawbale experimental wall [was wrapped with chicken wire, too]....which is still intact over 10 years later, with no further care given it...location: Pacific NW near Olympic peninsula.
I might be wrong, but the WeldBond addition, and the Pozzolan addition, seem to decrease crackage, increase water-resistance, and seems to decrease spalling from freeze/thaw cycles.
Pozzolan also makes cement more resistant to fire damage. It is sourced from volcanic ash, and from coal ash. It is extremely fine, sharp particles, so _do_ wear breathing protection when handling the powder. Once it's been wetted, it can cure like cement does, and, once wetted into the mix, is no longer a breathing hazard.

Wortex

9/5/2017 12:22:29 am

Thanks for the reply. I have not found similar discussion from forums and toughed that it is best to ask. My house is made of old tires, round wood, straw and COB. You can see it in here: http://www.thepoosh.org/buildproject/andres-andrekson/sassumaarja

To clarify, I do not plan to seal cob plastered walls with used motor oil - i am planning to lime wash. But I do plan to build other cob structures around the house like some sculptures or other design elements of the garden for example. Or extra elements for the bridge. In other words - structures that we are not in contact with all the time.

Everything forward is just a proposition and I hope we can elaborate on that. I would appreciate open discussion:

In here, folks use used motor oil to seal wood structures for instance, or dip the ends of a wooden pole in it before burying it. It is something we have laying around a lot - nearby farms with tractors, farming equipment etc. I mean - why use specially made petrol based sealers if used motor oil can do the same job with the same toxicity and is free. Goal there is to stop bacteria and fungus etc and oil seems to do pretty good job here.

But. Obviously we do not want the stuff to pollute groundwater or... any water to be correct.

But! It seems to me that even if the motor oil is not drying, when the oil has bonded with the material - wood and cob should absorb the oil and keep it in its pores - it should be "inert"? Right? The rain cannot wash it away? So it should stay inside the materiel indefinitely? I do not completely understand the physics in here but water should not be able to replace oil in the pores and gravity is not pulling the oil out of pores as well. Rain can wash of the oil which has not been sucked in by the material but it should be minimal.

As for other toxic elements inside oil, I am not sure how probable it is that those would be released. This would mean decomposing process of the oil but I am not sure how this works.

The other problem I can see is, how would the oil change cob-s properties. I suppose it may soften the cob.

Thoughts?

ErikRowberg

9/5/2017 06:25:47 am

I think your last paragraph is the issue you need to look into. would engine oil change the cob properties in a negative way?

Clay and lime are known to work/bond well together, making a strong water resistant surface while still breathing.

Linseed and similar oils harden over time exposed to air.

Engine oil you should find out how it bonds with your earth and whether it makes is completely waterproof so no water can escape.
I doubt engine oil makes the eath wall any stronger, most likely less.

Now that you mention it i might try painting some exposed earth garden walls with engine oil. I probably get more toxins riding back and forth to work than exposure to chemimcals in any product around my house.

Walrus

6/6/2017 05:58:12 pm

Engine or motor oil IS, simply a petroleum product thus is toxic and defeats the whole idea of natural building.

Linseed Oil (wonderful Linseed oil - the stuff of legends) is, was and always qill be a natural substance which has been used since time immemorial to preserve items for use around the house and work place. When we talk of "oil based paints" linseed oil is the vehicle or carrier referred to - yes paint can and has been used in paint and varnish for many things but please remember if you are going to use it it needs to be heated and the gases coming off are to say the least VERY volatile!

As Wolf warns above making paint with linseed oil in the old ways can be very dangerous! The flames can in an instance jump up to 6 feet (1.8 metres I believe)! And when it goes it really goes, hard to stop it - actually it's not so much the linseed oil that is the trouble but more the resins that need to be heated with it.

There are other ways - it has been used as part of a mixture to prserve boats since the Vikings and before - 4 parts of boiled linseed oil (dries quicker) and 4 parts of natural turpentine and 1 part of Stockholm Tar makes a nice 'soup' to paint your boat with. You'll need to read up on it before trying it but it works and works well.

Another use for linseed oil was that wonderous old waterproof thing "Oil Cloth" (I'm sure some remember it, if only the mention of the stuff) That was simply made from cloth that was impregnated with a few coats of Linseed oil mixed with glycerine (to make the cloth flexible) in a ratio of 95% oil, 5% glycerine and it works wonderfully - I have some in use at the moment, in the Devon environment so you can buess it does get 'damped down' frequently! I'll shut up now in case anybody else want's to get the odd word in!

Walrus

6/6/2017 06:35:39 pm

One final point (final - from me? you'll be lucky) when and if using linseed oil with or without anything else remember at the end of the day to dispose of all rags and cloths properly - on a rag that stuff spontainously (the Walrus dictionary works again!) combusts like crazy! Look the wrong way and a raging fire results, thankee for "listening" to this awld fool!

Atulya

6/6/2017 11:42:37 pm

Ha ha, ah nice to hear from you Walrus. I especially was interested in the viking boat building info. So this would also waterproof a roof I assume. And if I make it down to Devon, I'll shall look you up!

Walrus

7/6/2017 03:08:17 pm

Hi Atulya, it would be great to see you up here in Devon, but would you want to return to cold, wet England! I've just read my comment and yes it is true, proof reading has vanished . . . . . actually I never really had it! Thinking of waterproofing a roof, like all things a single entity would not do it, but used in conjunction with other items it would surely help and work well! the trick is to use many coats of the mixture and once in place maintain regularly to keep that coat whole! Buildings do as you know "settle" now and again and this cracks the coating which of course needs renewing, but it does not need renewing too frequently as to become a chore! Annually is normally adequate :)

Wolf Jordan link

10/6/2017 10:36:19 pm

About heating and cooking linseed oil, I quote mr. Walrus: "actually it's not so much the linseed oil that is the trouble but more the resins that need to be heated with it". Well, this is technically not so. There are no resins added to linseed oil. The drying process of linseed oil (and the other naturally drying oils) is, chemically spoken, a 'polymerisation', which means that the fatty acids start to form longer molecular structures. These are in fact natural resins. Those are all natural vegetable products. Plants take CO2 from the air thus reduce the quantity of carbon dioxyde in the air. Using plant matter helps us fight the climate problem. Telling this just to clear out the big difference with the synthetic resins and similar products, made from petrol...

Walrus

10/6/2017 10:56:45 pm

Mr Jordan (Wolf) I think you'll find that depends on the process that you end up with. If you are making oil varnish you first need to heat certain resins together until they are liquid and then add linsed oil and maybe turpentine, there are many varied recipes. If you are making paint some are just linseed oil and pigment whilst others require heating, pigment added, strained and aged - as I said depends on the recipe! May I refer you to Stephen A. Shepard's "Shellac, Linseed Oil & Paint" for a start, that gentleman certainly knows more about the various processes than I ever will for a start, your knowledge may of course be greater (if so could you please refer me to any disentations you have produced on the subject - I would like to learn more on the subject) Many thanks the Walrus

Wolf Jordan link

11/6/2017 12:06:48 am

Well, Mr. the Walrus, the topic was on treatment of cob with lindseed oil. The making of paint and certainly varnish, that's another thing. I am in natural paints (linseed oil, tung oil, lime paints, lime renders, etc.) for some 38 to 40 years now and my grandfather was an artist painter (Van Tongerloo), so I gathered some experience on this subject. Conc. varnish, we have a traditional marine varnish, made of a mixture of linseed oil and tung oil. We don't do this preparation ourselves, it is done by a company, founded in 1839 and they still make this traditional product in the old way. The oil mixture is carefully heated under pressure and the natural oils are transformed into resins. In this case, no other 'certain' resins are used. Some types of modern synthetic varnishes use similar types of resins as our varnish, but made from petrol origin. But there is a big difference between both type of varnishes, believe me. Not only ecological differences but also technical. The varnish made of natural oils is more elastic. For this topic, I would never have advised to use even a natural based varnish, since this will stop the breathability of the cob. Raw linseed oil and even boiled linseed oil will still result in breathable layers. The shellac you mention, is not to be compared with natural oils, that's something totally different. I have given many lectures and workshops where I explain (at least my vision on) natural paints, but I did not write any dissertations. What I started to do is writing a book, where I wish to share my knowledge. Best regards, from the Wolf to the Walrus.

Walrus

11/6/2017 01:02:33 am

Wolf sir, as with most "conversations" on the web in various places the subject had wandered slightly and I was under the impression that it was generally about the use of linseed oils in general following the old ways. Which is what I generally mentioned. As a mariner of some 37 years on various ships I became interested in the construction of paints and varnishes over the years however I merely dabble for my own entertainment (when I am not trying to set fire to myself!) The only mention of shellac I made was with reference to the tiltle of the book and yes to a certain extent it is different (made from the bodies of the shellac beetle mixed with denatured alcohol) but in some ways it can be as good as oil varnish - at least you don't have to heat the stuff! But it does require a lot of coats! It is however natural in every way! And Wolf when you finish the book you may consider at least one copy sold - to me! If I can find you when it is ready! (I wonder if Atulya could pass my email address on somehow?) Good luck with the book, best regards from the Walrus (and that's another interesting story)

Naomi Parker

23/9/2020 12:59:36 am

I am building with cob for the first time in Northern New York State. I plan to put a roof over the cob oven I am building, but was wondering if lime plaster or boiled linseed oil is preferable in a climate with hard freezes and at times drifting snow.

Ashhar Farooqui

16/6/2018 11:06:59 am

Hello all! Wonderful to find you. I'm currently applying double boiled linseed oil on mud walls. After 2 coats the finishing seems patchy. All lot of 'viens' become visible and also some parts are shiny like varnished wood while others are dull. I waited 24 hrs between coats. Really looking for an even finish. What am I missing? Thanks!

Atulya

16/6/2018 03:16:34 pm

It might be because of the actual plaster finish before you added the oil. If some parts were more compressed and worked smoother with a trowel, while others were left more porous, the oil will be absorbed unequally. But there may be another reason I'm not aware of, so I recommend posting your question on this forum: https://www.facebook.com/groups/naturalhomes/

waterproofing link

15/2/2019 07:02:19 am

For me, the above tips and suggestions are really helpful in preventing water from entering to the crawlspace. definitely, I'll follow the mentioned ways

Wolf Jordan link

4/5/2020 04:13:47 pm

A reaction for Arlene Saunders:

I see no direct "Reply" button on your question.
So, I hope this comes where it is needed:
Yes, you can delete your boiled linseed oil with turpentine for better penetration. The turpentine will partly evaporate and partly go into the chemical reaction of the oil and the oil will change into another substance, it is a 'natural polymerisation', so, once dry, there is absolutely no danger, don't worry. Your oven will not explode or something. Just wait a couple of days to let it dry. By the time you use the oven, both turpentine and linseed oil will not form any inflammable gases anymore.

JB_Plaster link

7/7/2020 02:42:11 pm

Thanks for sharing!
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Barry E. Holland link

18/11/2020 09:16:55 am

Nice Article...Very interesting to read this article. I have learned some new information. Thanks for sharing.

firoz dharani

22/4/2021 09:15:59 pm

I have read the correspondence above on waterproofing cob, it was most interesting.
Am in process of making cob house in kenya using black cotton soil. I can only afford to motor oil as waterproof, linseed is expensive.
I may even consider vinyl water paint, will thin it down to give peneration, any better cheaper options

Wolf Jordan link

22/4/2021 09:42:26 pm

Please note that motor oil really is toxic.Above you find reactions from several people confirming this.
Maybe look around in Kenia, how people traditionally treated the cob they used in building... Most local wisdom has been lost, worldwide, which is such a pity. Because our ancestors where very smart too...
As I also explained before, in many African countries where people used to build with earth/cob, they waterproofed those beautiful buildings with shea butter.
In other countries, like India, they add cow dung to the cob, which also improves the waterresistance. In many Arab countries, they did it with camel dung.
But please, don't use motor oil...

michal

24/8/2021 09:22:09 pm

Hi beautiful people,

i have a piece of concrete outside against the house wall, which every winter is full of water.
do you think i can put some dirt or mud, compress it, cover with oil, in a slight slope and it will be ok?
also, i fawned only synthetic linseed oil...(i think im going to try at the supermarket?!)

thank you for any advice

Best Access Doors link

27/5/2022 04:55:49 pm

Oh great! It is really possible to make something waterproof. It is my first time to know about this. I am going to research more about this linseed oil and how to use it more. Thank for sharing this informative ideas.

Cementitious Waterproofing link

17/10/2022 02:06:03 pm

Great explanation, Looking forward for more blog like this.

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Atulya K Bingham
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