Fire Resistant Earthen Houses

Hey Mud Family,
After my friend Chris' house burned down in the LA fires one of our mud buddies seems to have the ear of the LA Times right now to have a shot to talk fire resistant mud building and affordable sustainable rebuilding.
Ray Cirino who I've been building a fire resistant cob house with out on the Mojave still lives part time in LA not too far from Fire Central. The Ojai fire of a few years ago came within yards of burning him out.

The house we're building up there is made almost entirely out of the local sand and clay, with eaves designed to not catch blown embers in a fire, high mass walls to keep it cool inside and steel shutters to protect the windows


He's designed an updated adobe block, more like a mud lego, to speed up mud building and we think we've found a machine to manufacture them on.


So there's a bunch of us who are getting serious about pushing mud building to rebuild LA better, cheaper, and safer with mud. The data is there. The ASTM standards are there. The International Building Code now has an earthen wall addendum and the folks who wrote it live in California for pete sake. We have the architects and builders whose earthen buildings have weathered the fires. So what else do we need to do to swing things toward natural building?

If you had that two seconds what would you want people to know? What resources would you point them to? Bonus points if you've got something self promoting. Who has plans and engineering ready to go? Who doesn't care so much about all that right now and is just going to start sculpting something in the ashes with their friends?



Also Chris could use a hand if you've got coffee money to spare. webpage

Thanks for bringing this up.

While there are many things which could have been done, or might be done in the future, to mitigate the hazards of conflagrations such as we have seen recently, fire resistant construction seems to be low hanging fruit, especially since so much will need to be rebuilt.  Earthen construction (whether adobe, CEB or rammed earth - cob, too, if there is less of a time crunch) seems the obvious choice - climatically appropriate, environmentally appropriate, cost effective if done DIY or by neighborhood cooperatives and volunteer agencies.

In the Midwest of the US, from which we both hail, seismic engineering of earthen structures isn't generally much of a consideration.  In Cali, though, it is a primary design criterion.  I see that the bricks do have core holes, through which a tensile member can be run to tie the walls together.  Surface reinforcement may also be an option.

Th Australian government, both federal and more local, has considerable guidance available online regarding making structures more bushfire resistant.  Everything from eave details and roofing materials selection to landscaping ornamental choices.  We might take a page or two from their book.

Hmmm, my initial thought is perhaps overly cynical, but I'd suggest that this kind of paradigm shift won't fly at high levels unless/until people stand to make lots of money and cachet off it. So, what kinds of industrial scale earthen-like construction methods could be near-term commercially viable, while also providing  openings or cover for many more crafty hands-on vernacular approaches to slip past the permit desks? I would probably want to look closer at the potential for "3D printed" building systems, mostly cement based now but of rather similar massing and engineering standards to earthen methods. CEB would be another easily scalable, standardized system with ample advantage.

Kevin Olson wrote:In the Midwest of the US, from which we both hail, seismic engineering of earthen structures isn't generally much of a consideration.  In Cali, though, it is a primary design criterion.  I see that the bricks do have core holes, through which a tensile member can be run to tie the walls together.  Surface reinforcement may also be an option.

Here in Aotearoa we have recently seen our earth building standards updated and they're even freely available to the general public:

NZ earth building standards

We're in an active seismic region and there are several historic cob and adobe structures that have survived major earthquakes. A mate of mine is an experienced earth builder and his go-to designs are post frame with light earth infill. My project currently underway got a good shake (5.3) a few days ago and nothing cracked or changed.

Chris McClellan wrote: After my friend Chris' house burned down in the LA fires one of our mud buddies seems to have the ear of the LA Times right now to have a shot to talk fire resistant mud building and affordable sustainable rebuilding...

I sooo... wish I could give you some magic words which would convince the world that you are right.

I figured out in 1970 that California needed building codes that focused on defense from fire and I was still high school aged! OK, I'll admit a good marks high school student, but if I could figure it out, I figured the people who make the codes should be able to.

Unfortunately, I suspect it comes down to "follow the money". TV and Social Media tells everyone what their house should look like all across North America, and Fire resistance, nor Tornado resistance, nor Hurricane resistance, seem to get more than lip service. (And don't even get me started on earthquake resistance - here in BC the focus is on people getting out of the building alive, but that's it. If it's unlivable afterward, too bad, so sad even if it happens to be snowing like today!)

I do believe awareness is growing. I would collect every picture people can that show natural buildings surviving in a livable condition, ideally beside buildings in ashes. Maybe collect those pictures in this thread and then maybe try to get a famous talking head to get on board?

At least believe me - your friends here on permies are totally on your side!

I'm a supporter of masonry buildings for several reasons:
-cavity walls are nesting grounds for vermin, all the stick construction I have lived or visited had some insect and rodent problems
-it does not burn - of course contents or wooden roof structure can burn but house can be reused, arguments that concrete is destroyed by fire do not convince me - the amount of fuel to damage concrete is greater than available fuel inside the house, also masonry homes are actually being extinguished by firefighters in other countries; when a lumber building here is on fire, they just secure perimeter (I experienced it first hand when I had a local fire), so it will incinerate to ashes safely; also clay based masonry material are much more resistant to fire than concrete
-it creates lasting beauty, which is a very important factor - if not for quality building, France or Italy would not be the most visited countries in the world and it applies to other countries too
-stick houses are full of chemicals, retardants, plastics and allergens and no expensive finish will change it
-the houses are overpriced for the low material quality they offer; argument that the major price factor is location additionally supports quality build of lasting low maintenance materials - either way it will be only a fraction of the final cost

Good architecture is beautiful, functional and built from quality materials,

I don't know that you have realized that a lot of building codes revolves around fire: outlet on each wall, distance to flammables, egress windows, smoke detectors, sprinklers, firewalls, all to avoid noticing the elephant in the room: structure built from flammables.

Reading comments on youtube under 2025 LA fire videos I got convinced that people got programmed for a century that in earthquake areas you build from wood, but it's far from truth. Even Japan built only 55% wooden homes in 2023 and the rest of the world (except New Zealand) uses concrete skeleton with infill masonry material or structural bricks (for example Poroton in Italy) or concrete blocks/solid concrete.

Stabillized adobe would be a material of choice for California:
-ingredients abundant everywhere around. Lumber products seem easily available, but only because they are transported for thousand miles - frequently form Canada. In economy of scale, the CEB blocks could be very cheap
-thermal mass is perfect choice for a place with high diurnal temperature changes
-of course it does not burn
-the oldest buildings in California were built by Spaniards from adobe and a lot of them are still standing
Poroton or structural bricks would be even better choice, because like someone said - fired bricks have advantages of adobe, but none of its faults. Surely they need energy to be fired, but the structure will be strong and not affected by elements. Everything comes at a price. Aerated concrete blocks could be also used - they are very popular in Europe, are light and offer good insulation values.

Challenges:

Each custom home (and every masonry building falls into this category in California) has to have structural engineer plan and stamps. It cost me around $5k, but another $3k after revisions I requested. This bureaucratic barrier should be somehow broken. The best would be to prepare, let's say 10 designs of various layouts and sizes, prepare structural plans and be able to reuse them. I don't know how to approach it, because I'm not a "legislator" and I don't like "legislators". It would simplify the process and save a lot of money.

Vertical rebar should be continuous all the way to the bond beam and it creates a serious challenge: it's difficult to build from blocks if you have to stand 10 feet high (rebar height is some spots) first to put all of them. Solutions are either welding the rebars with 8000 type stick or use expensive connectors that require rebars to be prethreaded first. I chose welding, but welding rebar (weldable type) is not so easy.

Every third course of wall had horizontal ladder mesh. Stores stock only standard mesh for 8" block wall, so I had to custom order it for 24" and 16' wall. There are only two companies in US that make them, both in the East.

I was considering to use heavy lumber bond beam but my engineer said it was too weak, so I poured concrete one. It has rebar cage: 4 x #4 + #3 stirrups every 16' and is 10" thick. Here comes another challenge. In masonry building countries it's quite standard that concrete mixing trucks have concrete pump attached. Here you need to rent a separate pump and because it's quite monopolistic business the prices are exorbitant: $250/h and 6 hours minimum for boom pump (it was 8 years ago and I used it for 3 hours) and around $1000 for inline pump that can pump only pea gravel concrete and is very painful to operate if you want to pour bond beam on all walls (never again!).
For the forms I used 3/8" plywood attached to 3/8" all-thread rods (sitting on the wall and now they are part of the wall after cut flush).
Bond beam should have embedded anchors (5/8" every 24") for top plates if the roof structure if made from wood.

In California the house has to pass Title-24 - energy audit done by independent company to be included with building plans. It costs only $250+. Wall insulation may be omitted if sufficient roof insulation is provided.
My original plan for roof structure was: rafters -> ceiling planks -> box structure with wool infill -> roofing boards -> roofing material. I have simplified it, by using massive rafters in which I routed groves. I slid ceiling planks into the grooves and the 10" cavity is for sheep wool insulation. I did it because first of all it would be elegantly hidden within the roof envelope and would not look like a thick hat slammed on the walls and secondly - I have access to the insulation.
Nowadays I would probably pour reinforced concrete (made from white cement) vault instead. It would be probably cheaper than all heavy lumber and timberwork and I could insulate on the outside with perlite cement and lay rooftiles directly on it. Or I would build brick vault and reinforce it with concrete.
With cast vaulted ceilings there would be no flammables in the house structure and it would not require extra carpenter to build it.

The roof has traditional brick cornice built and rooftiles are laid on clay/straw mortar so entire house is protected by 24" CEB walls, 12' cornice and 4" solid masonry on the roof.

I have more detail to share if asked. It can totally be done and the limiting factor is not money or red tape, but just state of mind.

Cristobal Cristo wrote:... Each custom home (and every masonry building falls into this category in California) has to have structural engineer plan and stamps. It cost me around $5k, but another $3k after revisions I requested. This bureaucratic barrier should be somehow broken. The best would be to prepare, let's say 10 designs of various layouts and sizes, prepare structural plans and be able to reuse them. I don't know how to approach it, because I'm not a "legislator" and I don't like "legislators". It would simplify the process and save a lot of money.

Canada has already been proposing this for "regular stick-built" homes in an effort to solve our housing shortage. This was done post WWII when there was a huge demand for housing for returning soldiers and a large influx of immigrants whose homes and countries had been destroyed in the war. So it can be done and I suspect the best way to accomplish it, is with a groundswell of support by everyday people who don't want to rebuild only to risk loosing everything again.

And wrote:

... the amount of fuel to damage concrete is greater than available fuel inside the house...

This is another area where we *really* need to keep trying to educate people. I've seen videos of the difference between wool upholstery burn rate vs artificial material and the difference is scary. I've heard in many places, wool is being composted because farmers can't get enough money to cover the shipping. People do have to choose with their pocketbooks.

Rick Caruso, who built the only shopping center that survived the fire in Pacific Palisades, has launched a non-profit to help rebuild those areas with resilient buildings. Instagram has a CBS news story about his surviving shopping center and his future plans: CBS video about resilient developments The nonprofit is called Steadfast LA.

Jeremy VanGelder wrote:Rick Caruso, who built the only shopping center that survived the fire in Pacific Palisades...

I like the quote in the video where he says it was a "failure in preparation". To my ears, he wasn't trying to deny the reality that California is a "fire ecosystem," but that it's past time that people treat it like one.

Yes, he seems to be focused on tech solutions like concrete siding, over "mud" solutions which are cheap, local, and accessible, but I still see his effort as a step forward rather than ignoring the reality of that area's history of wildfires.