Ferro Cement

Check out the Ferrocement network:

http://ferrocement.net/

and here's another resource:

http://ferrocement.com/Page_1/english.html

and the story of how we built our tiny cottage which we've been living in for over three years. The cottage is a mix of RC, FC, stone and brick work:

http://www.google.com/images?q=site%3Aflashweb.com%20tiny%20cottage

and our current big project, our on-farm butcher shop, which we're building along somewhat similar lines:

http://www.google.com/images?q=site%3Aflashweb.com%20butcher%20shop

An important thing to keep in mind when planning projects is not to fixate on one particular material or technique but to utilize each to its strengths. This may sound obvious but I've seen all to many cases where someone forces one method (e.g., FC) to a purpose (e.g., foundation) where another method (e.g., RC) would have been far better.

Another key is to do models. Make little things. Then make a little bit bigger things. Make a dog house:

http://www.google.com/images?q=site:flashweb.com+%22dog+house%22

animal sheds, wood sheds, etc. This helps you figure out technique and how things go together, how you work. Practice makes, well, better than before.

Cheers

-Walter
Sugar Mountain Farm
Pastured Pigs, Sheep & Kids
in the mountains of Vermont

we have a little bit of info on Ferrocement on our site, and more on our blog (just search for ferrocement)

Thanks for all the great info. I am stuck in 2G network the next few days - so hoping that i can get more into the sites this weekend.

The weather is supposed to be warm so planting prep takes priority and I am starting some seedlings earlier this year. Vela, I liked the soil cube device and gave me an idea that will go well with something i was planning for seed starters..

I like the cottage Walt, Is the roof going to have a finish coat of some kind or is it finished? Sorry i haven't read everything as I am on the way to Cedar Falls Iowa and will have 2G signal for the next 2 days... It looks like that place is cozy..I love the design.

ronie wrote:I like the cottage Walt, Is the roof going to have a finish coat of some kind or is it finished? Sorry i haven't read everything as I am on the way to Cedar Falls Iowa and will have 2G signal for the next 2 days... It looks like that place is cozy..I love the design.

Eventually the roof will get insulated and then a top coat of more concrete and then it will get buried as the house is bermed. That has to wait until we build the tower and the wings. I want to wait on doing the final exterior stuff until the building is completed so it has a unified appearance to the outer shell. See this post which talks about that a bit:

http://SugarMtnFarm.com/blog/2011/03/kitchen-ice-feathers.html


Right now the barrel vault ferro-cement roof is just 1.5" thick. It is sufficient to get us from here to there while we finish up some other projects that became priority.

Cheers,

-Walter

Using less than a cord of wood to heat with is amazing. You're going to miss that wood fire after you insulate the roof and bury the structure as i can't imagine that design needing much fire after you get to that point.

Good job there Walt.

I have been working on a barrel vault design for years, but just about gave up on it as I had never heard about ferro cement  until recently. I was going to use wood -  I got side tract by Earthships and was going to use tires for thermal mass and walls... Some think that the tires may put off toxins - I'm not sure.. The tires sure are labor intensive..

I have more dirt and clay than stones on my place so was starting to consider adobe or cob for walls/mass. 

Thanks for all the links - I like Norton's castle - just wish I had those volcanic rocks on my place.

Thanks everyone for the great resources.  I have had some tips on where to read about this stuff, and heard the name Bo Atkinson, Roger Dean, Hubbel and Hubbel.  I'm just trying to hit anything I didn't notice above.

Aso see www.mortarsprayer.com.  A great resource for these techniques, plus a great DIY tool which I own and use to spray earth plaster on all my earthen houses.

Cement, although costly in energy, has wonderful useful properties, and shouldn't be totally denied.  It's hard to me to say this as a natural builder type because I always tell my students to avoid it when possible because we are all brainwashed into thinkin cement is the only way - hogwash!  Earthen houses can have great, cheap, long-lasting roofs of ferrocement or similar methods.  Kelly Hart recently told me about the new Magnesium cements that are not toxic and can actually enrich the soil around such walls.

I really want to get into some sculptural ferrocement roofs soon.  Let me know if you have a project for me.  I specialize in sculptural architecture, and you can see some at the link below.

Cheers,

I have been interested in ferrocement for some time, I just did not have a place to build with it - now that I have a small homestead I am working on a ferrocement building guide - right now I am working on a FC conduit dome and a FC cabin - but the intent of the book is to start with limestone, cinter it with clay to make the portland cement and build a variety of homestead projects from animal hutches and shelters, fencing, water storage and aquaponic tanks, and of course a few types of buildings.

I recently shot some youtube footage on slaking limestone and building the dome frame.

The book project is in its last week on kickstarter if you are interested in seeing the videos I have up so far.

http://www.kickstarter.com/projects/tngun/ferrocement-for-sustainable-living-a-guide-for-bui

cement has a negative reputation in regards to sustainability - but it can be made on site in small quantities and it absorbs carbon as it ages (which makes up for the carbon it releases as it is formed) - I like it because it is a flexible material that is inexpensive and owner buildable.

The bad reputation is not deserved. Concrete contains only a small amount of cement. Most of it is aggregate, that is to say sand and stone. Building with concrete or ferro-cement is very energy efficient, ecologically friendly and green. Realize that I do sustainable forestry so I should be telling you, if I was paying heed to my 'best interests' to buy more lumber since I sell lumber. But the reality is concrete is a better idea because it lasts so long. Wooden houses are typically 40 years, maybe 230 years like our farm house, rarely much more than that. Wood rots. Stone, mortar and concrete will last for centuries to millennia. That is why even though I have all the wood I could possibly want I build my own buildings out of stone, RC concrete and Ferro-Cement - they're green building materials.

Well, this is a very old thread but I hope my dilemma attracts a few glances, and thoughts.

I am about to put a barrel vaulted roof on a 4x8m (13'x26') room here in Morocco. The exact span measurements will be 14.4' wide and 5ft high, so a relatively flat arch! The plan is to do it on a metre or yard wide moveable form and to lay locally fired bricks down first so we have a really stunning interior for our permaculture classroom. A thin layer of cement will go over the top of those, then chicken wire, then 10mm rebar (3/8") in a welded mesh, then expanded metal lathe, then the cement in one go. A final layer over something for insulation, probably polystyrene, will follow.

The problem: My walls are not strong, being built of limestone with an earth and lime mortar, 1.3' or 40cms thick by 3 yds/m tall and split by 3 large arched doorways on one side. There's compressive strength but cohesive strength is minimal and there is no possibility for buttressing. I could put a couple of steel bars, say 1" thick, across the bottom of the span but would like to avoid that and achieve a clean space if possible.

There is an existing 8"x8" reinforced concrete ring beam atop 8 x embedded vertical pillars. I decided on ferro cement as I would like this roof to be self supporting with regard to shear forces or sideways thrust. The added weight of 2400 bricks for purely aesthetic purposes is a risk but they amount to less than 2000kgs/4000lbs which, spread out over 26' doesn't seem too much??

I have been advised to solve thermal expansion issues by simply having the roof sitting, unattached, held there by it's own weight and inertia, on a strip of asphalt along the ring beam. This seems to make sense until you come to the question of whether or not this roof will actually be self supporting or not. Should my ring beam be imparting strength to the roof as well as the walls, or will the roof take care of itself?

I have a tendency to over engineer things and am putting another ring beam on top of the first (because the first wasn't made very well in my opinion) but the more I get into shear forces and the like the more bamboozled I become and I don't want to knock these walls over. If any of you can illuminate me a little I'd be very grateful. I'll post up a picture of the project on the facebook page below tonight when the internet connection allows.

Many thanks and happy New Year.

Mark
Fertile Roots Foundation
www.facebook.com/fertileroots

Ditto the seepage. I built a ferrocement barrel vault roof on top of an earthbag walled cellar. I didn't seal it or anything. Only when it rains really heavily does it seep. It's not bad, not at all. Thoroseal is good, and pure portland/water as a final coat is good for dealing with any seepage.

I think the seepage could have been addressed 100% if I had coated the exterior in Thoroseal in the first place.

Ferrocement (and earthbags) are so great, and I would like to see many more people using them.

Abe Connally wrote:I've done a lot with ferrocement, including vaults, domes, water tanks, buried homes, etc.

One thing I can tell you is that IT IS NOT WATERPROOF.  That's right folks, it will leak, or at least, seap.  But, depending on the water source, the leaking can actually cure itself, as minerals get deposited in the cracks/pores, and the leak eventually stops.

To make it completely water proof, you need a final coating of Thoroseal or just cement, water, and acrylic.

Very fine sand and/or fly ash helps with the waterproof issue.

Cold joins are the biggest problem with water tanks, you need to reduce them as much as possible. 

Great content. Thanks for sharing. Here is a case study of a Trial practice i perforemed in one of my project which may interest you

<a href="https://constructorz.blogspot.com/2020/04/how-to-install-wire-mesh-for.html?m=1  "> Ferrocement / Seismic Retrofitting of Masonry Walls

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