alternative foundations and flooring

Hi everyone,

I've read many books and articles on building alternative buildings, but find it nearly impossible to find anything on alternative foundations construction. I've seen a few articles about rubble trench foundations, but wasn't able to find any really extensive and detailed information on it. the same goes for non-concrete flooring - there are bits and pieces, but nothing exhaustive, with details, drawings, pictures, lessons learned etc... as concrete foundations and slabs are 1 of the most expensive and energy/CO2 extensive parts of the house (if not the #1 in it), I would like to avoid building those, but I still need to build "on the ground" - i.e. no wooden flooring above the grade, on pilots, etc....
can anyone recommend a good book or link for those topics? does anyone have personal experience with it?

thx

Ianto's book has a pretty good chapter on floors http://www.cobcottage.com/node/82

I built our house on a rubble trench foundation and it has not heaved or settled at all since 2001 with winters down to -17F. They are easy and relatively cheap. Dig a two foot wide trench around the perimeter, place a perferated drainpipe at a gradual slope to daylight, place 6mil poly draped into trench from inside and filter fabric draped into trench on outside. Fill trench with clean drain rock and compact. I used round drain rock because it consolidates well with minimal compacting. If I do it again, I would probably put extruded foam board on outside of trench and pour grade beam against it.

I was interested in using Limecrete for a foundation and your post inspired me to have a google at it.

Have not found that much yet but did come across a site that says that the houses of parliament in London are built on a limecrete foundation so it must be feaseble.

http://ecoswitch.com/eco-build/eco-build-directory-1c-lime-as-building-material/

geo-polymer cement ? i dont think it viable to heat the poured cement for 1-2 days to 176F i want to use ICF also so really no

sticky_burr wrote:
geo-polymer cement ? i dont think it viable to heat the poured cement for 1-2 days to 176F i want to use ICF also so really no

Inertial confinement fusion should offer plenty of heat for that task, if you can get the system running. Are you going with laser-driven, or z-pinch? Will you use the standard FLiBe mix to re-generate tritium?

(kidding...I used to work in ICF, but not the ICF you intended)

Not all geopolymer requires heating beyond (warm) ambient temperature. These huge blocks were made outside  in France which is not exactly in the 176* temp range.
  http://www.youtube.com/watch?v=znQk_yBHre4

What about "recycled" concrete?  They tear up sidewalks all the time in my town, and I've seen big chunks of cement used from these sites before for simple garden walls and paths ... I'd love to see how they hold up building something larger with more structural needs.

briggsshore wrote:
What about "recycled" concrete?  They tear up sidewalks all the time in my town, and I've seen big chunks of cement used from these sites before for simple garden walls and paths ... I'd love to see how they hold up building something larger with more structural needs.

I think that's what's called "urban recycling".  Of course I can't find it now, but I had run across a site where some guy was picking up this concrete as you might select stones for a wall.  Then he'd build a section of wall using that used concrete, laying slab on top of slab, and cover it with either new cement or cob (can't remember now).

We are almost done digging the trench for our community house rubble trench foundation. But there is something we just don't understand....

Philip said

Philip Freddolino wrote:
place a perferated drainpipe at a gradual slope to daylight,

What does "to daylight" mean? Our trench is sloping, but we just don't know exactly what to do with the perforated pipe. Does it go in around the trench in a closed loop? or do we have to dig an exit trench for the pipe?
Ianto's book has been great in explaining all other areas.

Have people with a rubble trench foundation in a temperate climate found that enough water flows out of the pipe to sustain a wetland? Or should we only hope for enough to periodically moisten our garden?

Once we understand this, we will be well on our way to struggling with indoor plumbing!

Also, the other term for used concrete and urban recycling is "urbanite". Hope that helps in the searching!

ardillaDeneys wrote:
We are almost done digging the trench for our community house rubble trench foundation. But there is something we just don't understand....

Philip said
What does "to daylight" mean? Our trench is sloping, but we just don't know exactly what to do with the perforated pipe. Does it go in around the trench in a closed loop? or do we have to dig an exit trench for the pipe?

To daylight means the pipe needs an outlet, someplace for the water to go and drain away.

Here is a method that may be less labor intensive than a full stone or concrete foundation: build a series of masonry (stone) piers that will support your floor beams at 8 or 10ft. intervals.  In between the piers, hang expanded metal lathe and coat with mortar to make a 1/2 inch thick ferrous cement "foundation" walls.  You are still using cement, but only a fraction compared to a concrete stem wall.  You can increase the insulation factor by applying cob or something to the interior of the ferrous cement.

your roof is by far the most expensive part of your building.  Foundations and floors can be expensive, but they are not even close to the cost of the average roof.

For a decent floor, easy to do, and a decent description, check this out:
http://www.velacreations.com/cebfloors.html

The bit about concrete being so high energy/CO2 intensive is deceptive and a myth.

1) Cement is really what they're talking about, not concrete when they discuss the energy issue. Cement is the binder. Concrete is the mix = cement + stone.

2) Concrete is almost all local stone with just a little bit of cement in it. Thus when you build with concrete you're building with local materials. Do you avoid electricity because copper doesn't come locally? What about aluminum which doesn't come locally and is extraordinarily energy intensive to produce?

3) Concrete lasts essentially forever. Cordwood, cob, strawbale, timber logs, post and beam, stick lumber have very short relative life spans. There are concrete structures that have been in place for thousands of years. I built our home to last. Modern wood construction is only rated for 20 years. I expect my home to last 10,000 years. The next glacial period is the problem. Divide out any CO2 by that.

4) Concrete is ultra low maintenance. Once I built it I don't have to do anything. This further reduces the CO2 impact because with most buildings you're constantly reroofing, repainting and repairing them.

5) My foundation, walls and roof are all concrete so it is one unified object making it ultra strong. It floats in place and has both compressive and tensile strength (RC). It is earthquake, hurricane and tornado proof. Windows might break but the structure will endure.

But back to foundations: we did a floating pad with a ring beam thickening around the edge which sits on insulation and crushed stone keyed into the ledge of the mountain. This is similar to what is sometimes called an Alaskan Foundation. If you want it to last build it tough.

See:

http://sugarmtnfarm.com/home/cottage

and follow the links for more about the construction. The only reason I didn't use the ledge itself as my foundation is the ledge shifts and transmits heat/cold. That would be an option if one liked the temperature of the soil and didn't mind the water coming through - an issue here on our mountain.

Cheers,

-Walter
Sugar Mountain Farm
Pastured Pigs, Sheep & Kids
in the mountains of Vermont
Read about our on-farm butcher shop project:
http://SugarMtnFarm.com/butchershop
http://SugarMtnFarm.com/csa

I totally agree with Walter on these points. 

And as a side note, cement alternatives are available for your concrete (fly ash, roman cement, geopolymers, lime).

velacreations wrote:I totally agree with Walter on these points.  And as a side note, cement alternatives are available for your concrete (fly ash, roman cement, geopolymers, lime).

Good points. The fly ash is cool, just don't breath it although the same is true of any dust. It is supposed to make for far stronger concrete. For parging our walls we used lime in the cement mix with sand, fiber and colorant (iron oxides e.g., rust) to make buff parges for our walls. Like adobe but far stronger. Lots of neat stuff to play with. Another related trick is we parged on recycled insulation board. This produced a thin strong wall that is also insulated.

Well,  there are a couple of points. One is that the concrete that has lasted for hundreds of years is NOT the same concrete as we use today, most of the time,. The still existing concrete that the Naboteans used for water cisterns in the desert 1000s of years ago were apparently made from burned lime and local soils. The concrete of the Romans was also a combination of lime and local pozzolans from a nearby volcano. One structure built by the Romans ( I cannot recall offhand which one it was )still amazes architects as the tall columns are  still standing and apparently have no reinforcing as would be required by today's materials and techniques. The concrete of the Chinese palaces and bridges lasting until today was also lime based with various materials, apparently including a proportion of liquid made of rice /water but it didn't include cement as we know it today.

The concrete we use today is not nearly so strong and depends heavilly on other ingredients to give it flexibility to withstand earthquakes, even with extensive steel reinforcing it doesn't do that well. Look at what happened to the roads outside Los Angelos  http://www.youtube.com/watch?v=mcoHJHo8d6k&feature=related as an example. Not only does the cement we use now not have the strength that the Roman  concrete had, it is very dependant on  reinforcing from other materials/fibers to give it the characteristics needed to last at all under various stresses.  Today's concrete in and of itself is a very limited material., and if the stuff isn't made just right can  collapse because of something so simple as water has got into it and frozen, for example. 

My understanding is that Kalili developed the earthbag house technique partly at least in response to the absolute devastation following a strong earthquake, in which concrete and other structures not only collapsed but killed a lot of people doing it. You might want to glance at this http://earthbagbuilding.wordpress.com/2010/01/18/earthquake-resistant-earthbag-houses/ for a more recent example in Haiti of concrete vs earthbag housing in earthquake zones. The same results of superior earthquake resistance has been shown by straw bale structures http://www.youtube.com/watch?v=mtV04KAxDco

Also, light straw/clay houses have been lived in continuously for hundreds of years in Europe and are still occupied to this day. There has apparently been a resurgence in interest in this  because the buildings  have been proven  for so long. Many of them were demolished not because they didn't function but because 300 years ago electricity and indoor plumbing was unknown and it was cheaper and easier to knock them down than to remodel them..as well as a lot of people always think the new (or more expensive)toy/technology has to be better than the old.

There isn't any question that today's cement/ concrete has a place but  even aside from the environmental problems associated with its production, it seems a bit extravagant to proclaim it as the answer to all problems. 

Pam wrote:it seems a bit extravagant to proclaim it as the answer to all problems.

I didn't claim that. No need for you to exaggerate. I was countering the eco-buzz myth that concrete is so bad. It isn't. Also don't compare the worst of todays concrete with the best of 1,000 years ago's concrete. Instead compare the best we have with the best of the past. Fair is fair. Anything else is false advertising. There are lots of concretes made now that are going to outlast the old concretes. Concrete technology has vastly improved since Roman days.

pubwvj wrote:
Concrete technology has vastly improved since Roman days.

What do you base that on, when with the best we have now, we still cannot duplicate what the Romans did?

I'm not suggesting there isn't a place for today's cement, but it's interesting to note that since the fuss has been made about the impact the production of it has on the environment there has been renewed interest in cements which are less catastrophic to produce. In the process  architects are finding that other types of concrete binders are at the very least equally effective.  There is some very strong evidence that geopolymer cements were used to make at least part of the pyramids.  I am doubtful that anything we have today could match that performance, and they didn't need to fill the skies with pollution to do it.

Pam wrote:What do you base that on

Current research. Things have changed in concrete technology a lot in recent years and they are exceeding the old Roman tech, Egyptians, etc. Some people like to keep the myth alive that the ancients knew secrets we'll never know but the reality is different and not as romantic or mysterious. Science is good.

Interesting articles on Roman and Modern concrete

http://www.romanconcrete.com/index.htm


And I agree that concrete makes an excellent foundation, probably better than anything else.


I deal mostly with stick framed buildings. Frequently people point to old buildings, still standing, and allude to how well they are built compared to today. Sometimes they are pointing to only one out of several hundred, the others having fallen down or into disrepair long ago.

pubwvj wrote:
"The bit about concrete being so high energy/CO2 intensive is deceptive and a myth.

1) Cement is really what they're talking about, not concrete when they discuss the energy issue. Cement is the binder. Concrete is the mix = cement + stone."

you might want to read this concerning the reason why people are concerned about cement. Not only is the manufacturing of cement the 3rd largest contributor to CO2 but the other emissions from its manufacture are considered directly or indirectly to cause a number of deaths  each year, which I didn't know.
http://green.blogs.nytimes.com/2010/08/10/e-p-a-cracks-down-on-cement-pollution/

pubwvj wrote:


3) Concrete lasts essentially forever. Cordwood, cob, strawbale, timber logs, post and beam, stick lumber have very short relative life spans. There are concrete structures that have been in place for thousands of years.

This is what I was referring to when I pointed out that the cement we use today is not  the cement which has been in place for 1000s of years. What we use today, portland cement, is considered to have been invented in 1824 by Joseph Aspdin of England, so it's actually a form of cement less than 200 years old.

I'm sure your home is wonderful and will indeed last a very long time. However, I think it is unwarranted to imply that any house not built as yours is, is likely to blow away or fall down. and this is what I was reacting to. (As well as the comment suggesting that there is nothing to be concerned about regarding the manufacturing of cement and anyone who thought there was is wrong.)

Pam wrote:
..... In the process  architects are finding that other types of concrete binders are at the very least equally effective.  There is some very strong evidence that geopolymer cements were used.....

Pam,

I tried to make some geopolymer a few years ago based on the web info at the time.
Is there a more precise recipe now?
Mine never got warm, which disappointed me. And, they certainly never got strong.
I know it was my problem with the amounts etc, but it all seemed so proprietary.
I found a company that made some of the silicate products, but it was seriously wholesale,really OEM, and they didn't even have a retail outlet list for me.

I have moved to different methods because of that, but I am still interested.
(I am an unabashed experimenter, and would build a shed just to try it out if I had to!)

So, if you have personal experience with geopolymers, or know the recipe, I will appreciate some help,

jeanna

I keep trying to fix my spelling in the wrong window and erasing my message!

I am in no way even remotely a geologist , just got fascinated by the topic because of Davidovits' video about the pyramids http://www.youtube.com/watch?v=znQk_yBHre4 . He has a lot of info on the internet, some of it more useful than other. This is the one I have been using as a guide, sort of
http://www.rexresearch.com/davidovits/davidovits.htm#geopyr   What clays there are around here are not suitable for geopolymer  so it's been a bit of a challenge to find appropriate material. I was told with great authority by a geologist that there wasn't any kaolin clay in Saskatchewan but  recently found out that not only is there such clay but it is being processed on a commercial scale. I was looking for equivilient materials to try to  reproduce the "recipe" Davidovits used.  Since I am not a chemist either it's difficult to know what combinations of materials in what proportion will work. It's a bit like making a cake, using rice flour instead of wheat flour  or adding too much salt will make a huge difference in the final product.

There are a lot of people making variations on what he discovered (most of them giving him no credit at all  but claiming they invented it  ) so clearly there is no one 'recipe" and it really depends on the interaction of the various materials used.

The latest thing which has grabbed my attention is the cements used by the Chinese years ago, which included a "sticky rice soup".  As far as I can can tell (it's difficult to get much detailed info)  this was about 3% of the mix. So I have just bought a big bag of sticky rice, and once the weather warms a bit and I get some clay...

A couple of other links I found interesting are http://www.scribd.com/doc/12741093/Alkali-Activation-of-Natural-Pozzolan-for-Geopolymer-Cement-Production and
http://ferrocement.net/ferro/files/pozzolans-uwe.html

Wish I could be more help..

Thank you Pam,

My interest went the same sort of way as yours, but I tried a bunch of things that did not work.
i will look at the scribd article to see if it adds to what I have already.

thank you,

jeanna

This thread got a bit off topic and I, too, am looking for info about alternative foundations.  I am considering a rammed tire foundation under a slipform foundation wall.  It seems like it would be a perfect and inexpensive foundation, but I can't find any videos or other describing how it can be done, other than the earthship walls making an entire structure.  I was thinking to start on level ground and stacking two tiers all the way round the outside and then back-filling at least halfway up the second tier, and tamping it solid.  Re-bar could be driven through the tires at intervals and the foundation wall could key into this fixing it to the tire foundation.  Am I making sense?  At 3-4 hundred pounds each, I would think this would be more than adequate in all but the coldest regions of N. America.  I'd love to get some feedback on this idea.  Thanks in advance--K

I've also been thinking of a way to make a tire footing because of ease and cost. I have doubts about putting a stone wall on the tires that have been pounded down on the ground. Going below surface and adjusting to the soil conditions seems to be best to start a footing for stone walls. Any instability in the subsurface can have bad consequences to a rigid stone wall.

Have you considered  any of the dirt bag construction ideas?

I don't think there is much more stable than 400 lb tires on the ground stacked two high and pinned together with rebar and the slipform wall will act as a bond beam to hold it together as a whole.  Also, the foundation wall is only 30 inches high.  Timber posts will anchor in that.  Why would earth bags be more stable than tires?  I am not being combative.  I just need more convincing that I don't have a reasonably good idea.  Thanks for your comments--K

No I was trying to say to use the tires for the footing and then the earth bags for the walls.

I think that if you try to use the stone walls on a tire footing, it would be best to not place the tires on the ground, but dig down to stable clay or rock and put the tires on the clay. There are some things that makes me very uneasy about putting the tires on the ground and then putting a stone wall on the tires.

Mainly it is not so much your tire configuration that bothers me, but the ground beneath the tires.

Being someone who has worked with concrete for 22 years,I don't know where Walter gets the idea that concrete will  last nearly forever.just look at any 20 year old bridge or all the cracked,spalding and even rotting walks and foundations-I have repaired many and if there's steel in there it will eventually rust and pop the concrete.It's a common problem in concrete window sills.A problem that we have is that they are making brick and concrete to hard and brittle.If it get wet and freezes it will spall.With the damage I've seen to 20 year young foundations,I have my doubts they wall last as long as the 120 year old lime puddy mortar and rubble stone foundations that I very rarely get calls to repair.I'm not hating on concrete-I make a living from it-but it's very very far from a superior building material

As for maintenance free,look at any new home foundation or concrete floors or look at all the cracks in the floor at your local home depot.Properly fixing it is not a small or easy job.Plus it does not breath or dry out easily causing dampness and maybe mold and the concrete may even rot.

Harder and stronger is not always better.Movement and freeze/thaw can wreck concrete real quick.Softer(lower psi) concrete seams to hold up much better in the long term.From my understanding the ancient concrete that lasted so long is a much weaker,more flexible and  breathable material.

Glen

Ronie,
I got you now.  I am planning to excavate a flat spot into the gradual slope my proposed site is and then begin laying tires that I will backfill.  Seems like it would be very stable.  Washed rock on the inside and around the base on the uphill side.  The stone foundation wall is mostly a "toe-up" for the cob walls that will infill the timberframing, and because I like the look.  Foundation wall will be around 18in deep to support the 8in posts and cob that is 10-12in at the base. Slipform construction will have facing stones on the front and urbanite and 'uglies' on the inside.

Keithbien,

Will you be rounding the uphill side in a U - shape like Mike Reynolds recommends? (This would be very difficult to do with slip form.)

Also Reynolds uses machine packed earth around the outside...You mention packing around the tires, but I think that most folks are recommending a french drain or some kind of gravel trench with drain tile.

Won't the stone foundation wall conduct a  lot of cool into your place? Or do you have a plan to prevent the temp conduction?

castlerock wrote:
Being someone who has worked with concrete for 22 years,I don't know where Walter gets the idea that concrete will  last nearly forever.just look at any 20 year old bridge or all the cracked,spalding and even rotting walks and foundations-I have repaired many and if there's steel in there it will eventually rust and pop the concrete.It's a common problem in concrete window sills.A problem that we have is that they are making brick and concrete to hard and brittle.If it get wet and freezes it will spall.With the damage I've seen to 20 year young foundations,I have my doubts they wall last as long as the 120 year old lime puddy mortar and rubble stone foundations that I very rarely get calls to repair.I'm not hating on concrete-I make a living from it-but it's very very far from a superior building material

As for maintenance free,look at any new home foundation or concrete floors or look at all the cracks in the floor at your local home depot.Properly fixing it is not a small or easy job.Plus it does not breath or dry out easily causing dampness and maybe mold and the concrete may even rot.

Harder and stronger is not always better.Movement and freeze/thaw can wreck concrete real quick.Softer(lower psi) concrete seams to hold up much better in the long term.From my understanding the ancient concrete that lasted so long is a much weaker,more flexible and  breathable material.

Glen

Will you define, "... lime puddy mortar and rubble stone..." Is the puddy cement?

Also how do you make this soft concrete? Is it make wetter than the 'hard' concrete? Is it cured differently?

Hi,lime putty mortar is just lime that's been just made into a paste and left to hydrate for a few days,then added to sand to make mortar.Your basic lime mortar.I'm currently experimenting with weak concretes which is actually more like stablelized earth.I've also been playing with stablelized cob,which is cob with 5-10% portland in an attempt to keep cob from deteriorating when it get wet and freeze/thaws.

Another note on these 100+ year old lime mortar and rubble stone foundations that may be relevant to this tread.They are very loosely mortared.In a typical 18-24" thick foundation,the inside and outside 4-6 inches are mortared loosely,and the inside 12" or so are just filled with rubble,sand,gravel,etc.This method seams to have some advantages.First,if water does collect in the air space and freezes(much like in rubble stone foundations) there is space for the ice to expand without exerting force on the stones or heaving the foundation.Second,water can drain down the inner to the base and drain away.Also we have the advantage that theres give and flex in the wall that would help prevent cracks and off course the natural healing properties of lime mortar if it does crack.I'm building a cordwood sauna in the string and planning on a slight variation on this method.

glen

Good idea Glen.

I have always thought that cob needs some portland in it. How did you arrive a a 5% mix? How are the experiments going so far? Does it appear that the 5% cement mix will improve cob?

Will you be using soft wood for you cord wood structure?

When you put the water in the lime, to make a paste, you have hydrated it - so when you say you leave it for a few days to hydrate - do you mean that you leave it to 'set up' some or to oxidize or to evaporate some? Or what is it that is happening in the few days setting?

SO after you add sand to the lime paste then do you add dirt or clay to the mix?

Hi Ronie,I would not say that cob needs portland.I was shocked to find out how much harder and stronger cob was over some of the 100 year old brick I have worked with.I was trying to improve cobs weathering ability.I choose 5-10% because i read somewhere thats what was suggested for stabilized earth.I've build a cob oven and a cob moai out of stabilized cob.this is the first winter-its completely exposed and unsealed.I would say the stabilized cob is harder and stronger that regular cob which could be a building code advantage.

I'm luck with my property.To make cob I just need to put a shovel in the ground and I have mostly white ceder,which is perfect for cordwood.My first test with ceder and a line mortar worked very well.I used a very wet mortar with no sawdust and got very little pull back/shrinkage.

Lime absorbs a crazy amount of water,so after the first mixing,I let it sit for awhile then add more water till its completely hydrated.It's very important to completely hydrate lime.I do not had any soil to the lime mortar,but I'm curious to add some clay

Hey Glen,

You are lucky to have cedar and good clay source. I have good clay source, but it is under a lot of topsoil so i would have to dig quite a bit to get to it.

I guess saying that cob needs portland is not quite accurate. I think portland would be best for any uses that i would have for cob. I was thinking that the outer layer of a cob project would benefit from the cement to make it harder for moisture to get in from rain. Some folks have nothing better to do than re-coat their outdoor cob every year. I like things to not need yearly maintaining. (I also thought of using sifted wood ash.)

So if you hydrate the lime i guess you stir it often and have to stay close for the few days? Or do you just stir when you add water?

Did you notice Pam's post above? http://www.youtube.com/watch?v=znQk_yBHre4

It is a video where they are making huge stone out of limestone rubble , some clay and sodium carbonate.
I'm not sure if the sodium carbonate would be of any use for you or not -but if they are right - they have evidence that the  blocks will last for thousands of years.

Ronie,portland in the outer layer of cob may help or maybe not.I don't know the short or long term effect of portland in cob.What is known is that a line plaster will help and maybe even a natural sealer on areas more exposed to water.I may try wax on my cob over this year.

The lime is fairly easy to mix.I first mix it sloppy,let sit and then add more water before it get too thick so mixing is quick and easy.when it stop absorbing water I let it sit till it reaches a thickness thats right for mixing it with sand.If you keep your lime putty isolated from the air,ie in a container with a layer of water on top,it will stay usable for a very long time. The nice thing about that is you can mix large batches at a time and just use it as you need it.For example my place is 2 hours north of toronto,I can dig a hole,line it,mix a ton or so of puddy,use what i need,add lots of water,come back a couple weeks later,use what i need,then repeat the process.People have kept usable lime for a very long time like this.

All this going on about lime is find but I still don't think it's an ideal building material as it still has a lot on embodied energy.But as far as manufactured materials go it has a lot of benefits and a very long and successful track record,modern concrete does not! One thing I am very curious about is that since lime mortar are suppose to absorb co2,would it become offset the carbon produced in its manufacture at some point??