Skip to Content.
Sympa Menu

permaculture - Re: [permaculture] Ferrocement water tank pix

permaculture@lists.ibiblio.org

Subject: permaculture

List archive

Chronological Thread  
  • From: Keith Johnson <keithdj@mindspring.com>
  • To: permaculture <permaculture@lists.ibiblio.org>
  • Subject: Re: [permaculture] Ferrocement water tank pix
  • Date: Sun, 16 Dec 2007 13:11:13 -0500

Stella,
You can certainly combine multiple functions with ferrocement and many have. The links included in the document below clearly indicate the potential. As I mentioned I have built and lived with 5 of them over 20 years. The media lends itself to walls of homes or gardens and merging either with a tank is within reason. When combined with the walls of a living space you would need to be conscious of higher humidity levels as the walls of the tank will "sweat" both from very fine seepage (especially if you haven't sealed them inside and out) and from condensation. They can offer the extra advantage of being both a heat sink in the cool months (especially with sun on them) and a cool sink in the hot months (when they would need to be shaded).

The challenge with building thick walls-as-tanks is to make them stronger than a round tank since rectilinear forms are not as rigid as round tanks and the higher they are the stronger they need to be. A series of tall round forms would be MUCH stronger than rectilinear forms. Curves of course would add strength as long as the curve was into the earth (which is to say concave in relation to your view of them). Since you are proposing to use them as retaining walls you also need to account for hydrostatic pressure from moist earth and so, as you've guessed, you need to provide exits for ground water to leave which can be gaps and or drainage pipes behind the wall.

I'm not sure where you live but I get the impression that it's a warm climate, whereas if you lived in a cold region where the earth could freeze then frost heave would also create pressure on the walls. In either case you need to account for pressure from the earth side of your wall so that they don't gradually lean out and start to crack and leak.

Go to this page to learn more about the various types and characteristics of concrete media: http://en.wikipedia.org/w/index.php?title=Concrete&oldid=88108392 <http://en.wikipedia.org/w/index.php?title=Concrete&oldid=88108392>
There's an art to the proper mixing and curing of concrete for maximum strength (eg, keeping the newly set material wet for as long as possible to improve curing and reduce cracking, etc.)

As far as the durability of the media, LIFETIME"S" are not out of the question. There are stuccoed houses built in the late 1800's that are in fine shape today. Concrete was first made around 500BC and I've read that it can last 50,000 years under ideal conditions (a number quoted often in a bit of online searching). Concrete continues to cure / harden for 85 years and then it starts to slowly weaken. Salt water, acid rain, and freeze - thaw cycles take the greatest toll on concrete and will shorten its life substantially.

It can be made to look as elegant as cut and polished stone as evidenced by applications (which will likely long outlast the home) at this site: http://www.grottodesigns.com/html/faqs.htm

Keith

Stella wrote:
has anyone seen or tried ferrocement walls/tanks, as a multifunctioning idea?

i´ve never built a ferrocement tank, but fell in love with them in Brasil after seeing so many for the first time this year. Of all different sizes and shapes, and heard of very few problems with them (although of course this could be local bias..)

have been wondering if it would be possible to somehow combine two big jobs we have to do on our new finca: re-build & repair some big and small terrace walls, and build as much water storage capacity as possible. It would be very handy as the positions of the walls are perfect for both water capture and usage, and we'd like to avoid using much land for making tanks as all of it is good for growing, and we don´t have a lot...

the embrionic idea (so far... if nobody tells us it´s just completely crazy) is to build 'walls' as 1m thick tanks of ferrocement which could be as high as 2 or 3 m, dug into the earth about 1 to 1.5m, and as long as drainage allows (either many small 'tanks' with gaps in between for drainage, joint for support to one another, or install drainage tubes across the back and front walls).
it´s all totally at the initial idea stage, would love some advice from experienced folk.
no idea if it's been done but seems a logical thing to try, unless there are some contra-indications with the material of course.

here terrace walls are traditionally of stone (about 50-70cm thick, big stones with small 'fillings') and drainage is provided by the natural gaps in the material (cement is only used in some 'modern' versions). And most of our walls are curves (we have crecent-shaped terraces), so that would help, am guessing.

in Brasil we were told on various occasions how suprisingly strong these tanks are, even outside 'reccomended' sizes and shapes (normally given in books and literature).

what am wondering about, is ..

1) if anyone has tried this / has similar practical experiences that might help (not having anyone here with a 'feel' for the material but yes some fairly good basic notions of pressures, etc, this is a semi-blind guess)

2) the life expectancy of cement .. I suspect these tanks arent' 'for life' as we were told ... but just how old are the oldest one we know about? anyone tried it with lime? (cal)

3) how the ferrocement would be affected by constant contact with earth on one side, water on the inside and just air on the other side (long-term)


thanks for all the sites you have sent! will go study them with time ..



El 15/12/2007, a las 7:02, Keith Johnson escribió:

The steel rebar and expanded metal lath give it strength and the mortar
gives it rigidity. The two combined make it VERY strong. Very large (130
f) ocean-going boats <http://www.ferrocement.org/> are made with this
technique (the Brits built a 120 foot submarine) and their walls are not
much thicker. Many homes are built with it.

This is my fifth tank and my second 10,000 gallon one. We intend to add
onto the tank a ferrocement room that wraps around a third of the tank
and will serve as a root cellar, storm shelter and spring house
(utilizing the overflow). The tank will be bermed about 3 feet high
around the rest of the circumference. Freezing has not damaged our
tanks, though the coldest climates would require more extensive berming
or partial burying.

The cylindrical shape itself is a principal source of strength as the
outward pressure is equalized over the entire surface. The overall
thickness is one to one and a half inches. The walls are not thicker at
the bottom of the wall than the top of the wall. The roof is the same
thickness. When empty, it rings like a bell when you whack it with a
rubber mallet. If you sing in it, it echoes nicely. A really lovely and
versatile material and well worth the embedded energy.

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

http://www.ferrocement.net/

http://en.wikipedia.org/wiki/Ferrocement

http://www.thefarm.org/charities/i4at/surv/ferro.htm

http://www.green-trust.org/2003/ferrocement/default.htm

http://www.eugenesargent.com/bench1.htm

The stone gutter you refer to WAS essential to direct a large flow of
water into a sinuous garden path that provided many infiltration points
to prevent erosion in a very erodable landscape.

Lawrence F. London, Jr. wrote:
Keith Johnson wrote
Peter and I recently finished laying pipe to plumb our water tank and
have started to install the roof catchment parts of the system.
You can look at pix of the project at
http://picasaweb.google.com/KeithDJPcA/FerrocementTankPix02

Nice work. What design factors are required to give it enough vertical and circumferential structural rigidity to keep
it from bursting from hydrostatic pressure and is the concrete thicker at the base that near the top?

http://picasaweb.google.com/lh/viewPhoto? uname=KeithDJPcA&aid=5141688084664055841&iid=5141688179153336402
The stone gutter in this pic is just like downtown. I used to build some of these for landscape customers.
If you have a lot of flow this feature is essential.

--
Keith Johnson
"Be fruitful and mulch apply."
Permaculture Activist Magazine
PO Box 5516, Bloomington, IN 47407
(812) 335-0383
http://www.permacultureactivist.net
http://www.PermacultureTradingPost.com
Switch to Solar Power the Easy Way
http://www.jointhesolution.com/KeithJ-SunPower
http://www.PowUr.com/KeithJ-SunPower
Blog: http://kjpermaculture.blogspot.com/
also Patterns for Abundance Design & Consulting
http://www.permacultureactivist.net/design/Designconsult.html
also Association for Regenerative Culture
http://www.ARCulture.org
also APPLE-Bloomington (Alliance for a Post-Petroleum Local Economy) It's a small world after oil.
http://www.relocalize.net/groups/applebloomington
also Bloomington Permaculture Guild

_______________________________________________
permaculture mailing list
permaculture@lists.ibiblio.org
Subscribe or unsubscribe here:
http://lists.ibiblio.org/mailman/listinfo/permaculture
Google command to search archives:
site:https://lists.ibiblio.org/sympa/arc/permaculture searchstring



_______________________________________________
permaculture mailing list
permaculture@lists.ibiblio.org
Subscribe or unsubscribe here:
http://lists.ibiblio.org/mailman/listinfo/permaculture
Google command to search archives:
site:https://lists.ibiblio.org/sympa/arc/permaculture searchstring





--
Keith Johnson
"Be fruitful and mulch apply."
Permaculture Activist Magazine
PO Box 5516, Bloomington, IN 47407
(812) 335-0383
http://www.permacultureactivist.net
http://www.PermacultureTradingPost.com
Switch to Solar Power the Easy Way
http://www.jointhesolution.com/KeithJ-SunPower
http://www.PowUr.com/KeithJ-SunPower
Blog: http://kjpermaculture.blogspot.com/
also Patterns for Abundance Design & Consulting
http://www.permacultureactivist.net/design/Designconsult.html
also Association for Regenerative Culture
http://www.ARCulture.org
also APPLE-Bloomington (Alliance for a Post-Petroleum Local Economy) It's a
small world after oil.
http://www.relocalize.net/groups/applebloomington
also Bloomington Permaculture Guild




Archive powered by MHonArc 2.6.24.

Top of Page