As a member of the UK/France CobBauge research team, we have produced over 30 KZread videos related to this composite wall building technique.

At around 5.30, you depict what appears to be a polyiso insulation panel between two layers of cob. Polyiso insulation is not vapor permeable, but rockwool (e.g. Roxul) is vapor permeable and has a high r-value. Something to keep in mind.

Nice video. Looking forward to a video where you show how to practically make a dual wall (e.g. combination cob/light straw clay or rammed earth/hempcrete, etc.).

@KernSutton

10 ай бұрын

:59 and forward here shows a method- kzread.info/dash/bejne/mZN2y8Wrnbnfp7A.htmlsi=Ed29Q-97JjrPPKnI

R value is one of the greatest cons in the building industry because it isolates the material from real conditions before testing it. It doesn't account for air flow, sun exposure, evaporative cooling, passive heating, porosity to name a few. Condensation on glass fibres rapidly erodes its r value but nobody ever tells you that. Nor do they tell you that it's saturated in hyper toxic formaldehyde and will off gas in to your house for its entire life. Cob is so much more than thermal mass. It's straw fibres break up the conductive path of heat transfer. The clay modulates humidity perfectly to the most comfort and healthy range. No other wall material can do this. R value is a giant profit making lie for building product manufacturers. That's all. The genius of traditional cob foundation building isolatrs the ground inside from the external environment and once it has dried out it cannot be a source of evaporative cooling. This is why old cob cottages always feel so cozy inside. Condensation never occurs on cob. Condensation is the biggest enemy.

We are planning on doing Strawbale with Cob on the outside and inside.

I'm interested to see the slip form cobb video in the spring. I love cob as a building material, but the structure and organization of a slip form appeals to me a lot more than the free form of traditional cob buildings.

@thiscobhouse

Жыл бұрын

Stay tuned! I'll be building the foundation for that structure in March, and we'll begin cob construction in May.

@AnxiousCowboy

6 ай бұрын

What’s slip form mean

Mr. Cob . Sir. I have almost Summer with temperature 38 to 45 degree most of the year almost 9 months. No snow. Low rain. In winters temp not less then 10 only for few days. Mostly we have 20 to 10. So what kind of Insulation we need for Cob walls ?

There's plenty of different vapour permeable insulation materials, at least here in Europe. Wood fibre, hemp fibre, flax fibre, cork, wool… They're not structural, but some of them come in batts/blocks as an alternative to loose blow-in materials. I think wool is a seriously undervalued insulation material with some interesting properties, comparable to wood fibres, which is otherwise my favorite. When it comes to moisture, it's important to ensure that the outside is more "vapour open" than the inside. The innermost layer should slow down moisture. In wood fibre insulated timber walls, we use a (relatively diffusion open) vapour retarder on the inside and an even more diffusion open wind break on the outside. When sandwiching, it's important that the insulation layer is able to transport moisture to the outside. Glass/rock wool fails in that regard. If it condensates and runs down due to gravity, you've got a big problem.

I wish we were neighbors. I would build me one of those cob houses too.

For the dual wall system, the hemp/fiber exterior wall is not load bearing so what happens at the top of the wall? Is there a header poured that the fiber wall can support, or is the roof only attached to the earth interior wall? Thanks for the information.

Why are you not useing the berk wall tie system. Seems it would work well with the venter insulation style ,or really any of the form styles. The bad part is all the plastic cones left to dispose if when the wire ties are broken off. Still a great system

I live in Nova Scotia, I'm not coastal but I am considered in the Snow Belt. Currently dealing with 4ft of snow. Is cob a viable solution for building? Most of the components I can source from my farmland. Could I do cob/strawbale for insulation? Was thinking of using straw bale for the centre and build cob walls around

7:30 _Unfaced_ fiberglass, the type that has no paper on either face, is vapor permeable. But the type with paper facings is much more vapor retardant. It seems like one advantage of this approach is that you an run your wiring inboard of the cob wall, which would make things a lot easier, both for the cob and the wiring. I'm curious about the possibility of putting mineral wool insulation against the outside of the cob. This would keep the good thermal mass of the wall on the inside of the insulation, which is where we'd really like it. But it means we need to come up with a way to get an exterior finish on the mineral wool. Wood siding would obviously work. I know that standard cement stucco is done over mineral wool. But cement stucco is vapor retardant. Maybe something like a lime plaster would work better?

@thiscobhouse

Жыл бұрын

Thanks! Sure, a lime plaster would do well as an alternative to the cement stucco.

@mouthfulacoque3580

Жыл бұрын

if you intend to use mineral wool within proximity of living spaces, landscaping cloth an keep the insulation from getting in the air

Have you considered curved forms for your house? i think i may do that with my future home.

@thiscobhouse

Жыл бұрын

Yeah. They're just a lot more challenging to build curved.

Why not Wood fiber insulation mounted on the outside. E.g. Steico

I really like the idea of wattle and daub, though of course low R value. Any thoughts on a double wall with wattle and daub with the gap between the two walls filled with straw?

@thiscobhouse

Жыл бұрын

You might as well just built a straw-clay wall, and add earthen plaster over the interior and exterior. Just a thought.

@HeroOfTime303

Жыл бұрын

Straw bale and timber frame would work...you can just daub in between the timber and you do it straight onto the straw bale as the lath for daub. You would have a nice aesthetic look with that combination.

@231rft

Жыл бұрын

Pallets filled with straw and mud plaster on bath sides would be similar to that. Check out sir cobalot.

Is hempcrete something that could be used? I don’t know much about it but the internet says it’s vapor permeable. And in the dual wall type of insulation, will it still have the moldable, cob feel/look to the walls? Or is that going to change how it looks?

@thiscobhouse

Жыл бұрын

Yes, absolutely. Hempcrete is a good insulation layer for this too. The walls will still be rendered with lime plaster in the end so they'll look like cob walls.

I want to know how to do a roof, because I want to build a cob house but I want the roof to be rounded.

How about, instead of making a form for external insulation - make big blocks of this insulated material and fix them somehow to the wall? That would be my personal go-to, because it's easier than dealing with a custom form.

Do you know the R factor for insulated Cob? Also, what is the disadvantage of straw bale to make you go to insulated Cob?

@thiscobhouse

Жыл бұрын

The R value will depend on the thickness of the insulation layer, if you're doing the dual wall system. This is not to show one system being better than another (cob vs strawbale). It's just to give people options. Codes may require insulation levels not met by regular cob, so having options is always good. In my personal opinion, I would do an insulated cob over strawbale though. I just feel that a cob hybrid system would last a lot longer. I have some doubts about strawbale in the long term.

My adobe walls are extremely insulating! Feels like I left the AC on inside on a hot day.

@thiscobhouse

Жыл бұрын

Yes! It is amazing, isn't it!? I only recommend insulating cob/adobe walls when necessary.

@patandersen4271

Жыл бұрын

Wow that's great @mutantdustbunny

@godaboveall8344

Жыл бұрын

How about in winter below freezing temps that's what is the concern

The guys at Abundance Build Channel use styrocrete which has some pretty crazy R values. I wonder if you could incorporate shredded styrofoam into Cob as an insulator? I wonder how that might affect it's R value?

Seems like a slippery slope using more and more traditional materials and methods. If insulation is needed, why not just go to straw bale construction?

@thiscobhouse

Жыл бұрын

Yes, and sometimes this is the thing to do. It all just depends on your situation, environment, and what you want.

@mouthfulacoque3580

Жыл бұрын

have you heard of something called a hospitable environment?

I know a lot of builders are trying to pacify the building code monkeys by hybridising cob but it defeats the fundamental strength, litteraly, of Cob. Cob works exactly because it is monolithic. If you start burying stuff in the middle you will weaken it. You will loose the passive humidity modulation it does so well. Insulate the roof by all means, thats where its really needed most. Use plenty of straw in your mix if you want to raise the r value. Because of its dynamic living nature, Cob is not like glass bats or polystyrene foam ! Lab tests mean nothing in the real world. Cob is tougher than concrete. It is self healing and self reinforcing. It exploits gravity instead of fights it. Dont mess with the formula to indulge the building industry mafia. They have a lousy track record. Straw bale and rammed cement cowboys have done a lot of damage to earth buildings credibility. You cant improve this system. It's already tried and tested and proven.

@thiscobhouse

8 ай бұрын

I agree with you. But I do like to explore options, so people have them available just in case. I just see more options as more opportunities for different situations. I'm not a fan of strawbale, and I do see the majority of rammed earth is just mostly concrete at this point. I've steered away from stabilizing the earth wall materials.

@joschmoyo4532

8 ай бұрын

@@thiscobhouse Good man ! Cob is the common man's building material but if we allow the code Mafia to reinvent it they will kill it eventually because it threatens their toxic extortionate industry. They will do to Cob what Monsanto did to crop's. Where I think you can explore is using other fibres than straw that are organic. Gorse used to be a straw substitute. Reed and Bamboo perhaps. But in the end straw works so well and it's easily available just about anywhere. Straw bale is such a con ! But it appeals to those who want Lego speed results. Cob can be done fast with a crew of three or four. I mixed mine with a rotary tiller and tractor. Formed/ shuttered Cob was my method. You can get higher lifts without having to worry about slumping.

If you are going to claim Cobb homes don’t have insulation value then you should take a thermal view of the house other wise me personally I can’t take you seriously. Not saying you are wrong just saying you are a minority.

@thiscobhouse

Жыл бұрын

I'm not the one making the claim. The tests have been done, and the insulation value for cob is even written into the cob building code. A two foot thick cob wall has an R value of about 3. That's not significant insulation. Cob has significant thermal mass, not insulation.

Just go bale cobb and call it good? Focus on a decent heating method.

Never stop posting! I love this channel!! Get the following you deserve > "Promo sm"!!