The foundation training  was designed in the following order:

1. read the text below
2. Watch the ZOOM support session (sandslab) > Q&A for the text
3. Watch the lesson - Foundation Part #1
4. Watch the ZOOM support session (non insulated) > Foundation Part #1

FOUNDATIONS

ZOOM SUPPORT Q&A CALL IS BELOW

There are a lot of various foundation types for a variety of climates and soil conditions as well as weights of the structure. After this document I will present you with 3 video lessons to back and explain this text.

1. 3D render of a sand slap with tire foundation presented during this Sunday
2. Uninsulated foundations I used in Brazil and at my own building site 
3. Insulated foundation I will build with as soon as the ground thaws in April 2023 

The video lesson with uninsulated foundations built in the trench will follow straight after this doc, and the other video with insulated foundation will follow in May 2023.

The foundations range from super expensive to super cheap depending on the speed you want them done in and what effort are you prepared to put in.

If you want it fast and with minimal effort from your side then prepare to pay. I.e. wooden formwork above ground with concrete truck automatically pouring in mixture over reinforced steel.

For the sake of our course I want to present to you 1 method in detail that I will be using myself and I will explain to you other methods in warmer climates from my own previous builds

1. Super adobe or Rammed un-stabilised earth into tires on a sand slab NEW
2. Rammed un-stabilised earth into tires into a trench - Pskov build
3. Stabilised earth Super Adobe placed in a trench - Pskov build
4. Concrete pored into a trench - Brazil build 
5. Concrete poured into a wooden formwork - Aircrete Harry

Keep on mind that for warmer climates where the ground does not freeze, one can get away with a lot simpler and easier foundation methods. At Cal-Earth we just used a 1 foot wide bag for foundations and the same bags for building of the actual dome or curved wall. NB: Remember that a wall with curves is self supporting!

NOTE that a light weight aircrete dome weights 100s of times less than an earthship, so foundation to support aircrete construction does not need to be as strong as the foundation to support a MASS home. Thus said a foundation for an aircrete dome in sandy soils can be literally made just by throwing and slightly compacting gravel in a trench. 

One of our students in India did just that and build his 5 room aircrete dome home above it. For sand bag or aircrete dome in warmer dryer climates it could be a viable quick “bed” for a 1st row of sandbag to start off with. Gravel, once slightly stomped will not compress any further. If you are choosing this method please do your research. 

In my subzero climate and wet clay soils,  the trench with gravel will end up being full of water. If uninsulated properly it will ice up and may result in a wall cracking. 

In this training I’ll focus on a robust and low cost foundation method that can be applied for a variety of climatic conditions, soil types, as well as underground water levels. 

The Wautillarium is a heavy puppy, being buried by earth it needs to have a solid foundation that will hold the walls that in turn hold the beam, that holds the vault, that supports 3 feet of earth and 3 feet of snow above it.

I will discuss the most difficult condition, aka worst case scenario, such as really high underground water table (water is 1-2 foot below the surface of the earth),  super cold subzero winters, where wet soils turn to ice, up to 4 feet deep and thus expand, and we have wet expansive clay soils. This is what I have to deal with, where I live.

Worse than this could be living on a marsh land where the water is at the surface or sometimes even above it. In this case deep concrete pillars or as Mike Reynolds recommended huge bus tires filled will gravel. Keep in mind that the house will sink over time. Do your research if you are planning to build on a marsh. Usually it is not allowed. St Pietersburg has been build on marsh land and they are excavating an entire 1-2 storeys that have sunken over time

If you are not encountering one or more above conditions then you could make changes that will low the price and energy input for your foundations

In all of the below scenarios, foundations need to have a plastic water barrier so the moisture does not wick up. Unless you are living in dry desert then make a call about the placement of plastic barrier. Earthships always use plastic in the first course of tires, it is their standard tried and tested practice. 

Below are the changes that I could recommend that could save some of your energy and money;

• Low water table - then you can just dig a trench and place your foundation in it. No need to make a sand slab to place your foundation above, unless you want to speed up by not digging any trenches. 
• Ground does not freeze - you don’t need to insulate the foundation. If you are in a warmer climate then building a home straight on the sand bag foundation that’s wrapped in plastic is good enough. If wet ground then do a trench to dry up your site. Wet clays will sink and move your home
• Sandy soils - sandy soils have good drainage so unlikely they will make a house move. Water wicking up your wall should not be an issue. 

In our cold climate the traditional method, which is relatively costly is: 2.5-3 foot deep foundations: loads of rebar with concrete poured over it, into the formwork. Then the entire foundation gets insulated around the perimeter at least 3 feet deep or deeper depending on how deep does the ground freeze. Area specific.

The foam can be used as a formwork to pour concrete into. It is not the method I have used or will be using due to its high cost.

In the cold subzero climate, John Hait recommended to create a skirt of insulation as much as 3-4 metres 9-12 feet out all around our home Sometimes even bigger). Thickest insulation of 1-2 inches right next to the house and and halving it / thinning it out for every 1 metre metre away from the house. This method is the one I will present to you in May 2023.

Because our home is warm which keeps the ground above freezing, coupled with insulating the top of the ground, just a foot or less under the surface, gives us a scenario where the ground below and around the home does not freeze up. 

By utilising this foundation method we avoid:

• Digging 3-4 feet down - which is hard work 
• Insulating 3-4 foot down - which is costly 
• Using wooden formwork - wood had sky rocketed in price
• Using expensive concrete and steel (this is what makes sure that foundation is monolithic

After building quite a few structures in different types of soils and climates, I recommend doing a foundation using just one course of tires {215-75-R15(27.7” x 8.5”) } with Hyperadobe going straight onto the tire foundations. The “porcupining” method with nails “glues” the wall to tire 

The wide tire footing allows for a wide surface area that distributes the pressure of  the heavy wall mass. The UNDISTURBED earth will not “give in” due to such a large surface area of the tire. Very important to note that the earth must not be disturbed, before placing the foundation. Disturbing the earth can be achieved by using the pick too deep or ploughing the foundation trench with a spade, DEEPER THAN NECESSARY.

Having undisturbed earth is crucial should we want to get away from using rebar and stone infused concrete. In the practical session, that will follow this document,  I will show you how we “shaved” the level final bit of soil.

NO DIG FOUNDATION ON SAND SLAB

The Video lesson with insulated foundation on a sand slab I will present in May 2023 as it will be the method I’ll use in my own construction. This Sunday I’ll present you with a 3D render to visually explain this method. In future you will be able to watch this recording on this link

No dig foundation on a sand slab is one of the fastest and lo-tech methods I’ve seen done in cold climate. Yes the price of sand + delivery VS digging to undisturbed earth.  

This method is performed in the following way:truck or two of coarse sand gets spread out 30 cm / 1 foot high over the area of the home + 1 metre / 3 feet extra all around. 

The rain and snow will naturally compact the earth over the course of 1 year and thus no machinery is necessary to compact this sand.

This is an excellent method especially if you have a super high water table. It will make sure that the home is risen well above the wet earth, and will keep the foundation and the home dry. Due to large grain size, the sand does not allow any water to wick up. You also skip a step of doing any digging. 

The site should obviously be cleared of any logs and large biomass. Lawn and low shrubs will just rot under the weight of sand and one year later it is good to build upon as is  

In the case of wautillarium there are some technologies that are going to be placed underneath the room, such as:

• Low lying oven to pump heat under the floor. 
• A space under the sauna to collect the manifold for the air ducts of the passive heating system.

I am preparing a detailed drawing for you which I will present shortly on how I will be achieving this method for the wautillarium home. The thinking is to avoid placement of sand where one needs to dig down. As I said this will be explained in the drawing  as well as in the practical lesson following may 2023. By that point I will have the practical experience of what worked and what did not so you an follow a perfected methodology.

Sand Slab will work well if you are in a swampy area and thus forced to build your whole home above grade. In this case the air channels, that will be discussed in one of the next video lessons, can all be placed on sand slab as well. In the cold climate before placing sand slab I will place insulation. The insulation underneath will turn this dry sand slab into additional mass that will  assist with temperature regulation.

Once the sand slab is compacted, wether naturally during the course of 1 year or with a machine; then one just levels out slightly and then manually stomps it to accept one of the following foundations:  

1. Rammed stabilised earth in a bag 
2. Rammed raw earth in a tire
3. Concrete & rebar poured in a formwork.

I.e. The foundation goes straight on the levelled compressed sand.

The method foundation that will support the wautillarium home is to use a pickup tire. I’ve chosen it for a variety of reasons:

1. We clear up a plenty of hard non biodegradable waste from the dump that otherwise would pollute the earth. Tires in a huge pile at a dump are prone to very toxic fires
2. The steel encased rubber tire provides a little amortisation for any earth movement. 
3. It is one of the best and free formwork containers out there.
4. If rammed correctly and kept dry, if clays are used, they are extremely strong on compression. 
5. They provide a wide footing so the wall does not sink down.
6. The are free and I even got paid to remove them from the tire replacement workshop which covered my petrol. Delivery to your site is usually the only cost associated with them.

I will be experimenting with doing an insulation barrier before I place a sand slab, but one needs to prepare a slightly Convex shaped “lens” first. This is done in order for the water not to pond under your home causing insulation to be wet. Insulation impregnated with water looses its R value. 

1. I am planning to use a little bit of sand to shape this lens,  
2. then place the foam non compressive insulation on this lens
3. Then cover the rest 30 cm / 1 foot of sand above that

The skirting around this slab will be done after the foundation and stem walls are build. The skirting will start from the walls of the house and “fan” out  like an umbrella as much as 9 feet away. As I mentioned this is done to prevent the ground from freezing up. Expanding ice in soil causes cracks and failures! Skirting will be discussed in one of the future lessons.

Please note, sand slab is tried and tested however I will only be able to quantity the result of placing the insulation under the sand, during the winter 2023/2024. If all goes well the1 foot of sand slab with the ondol super adobe channels that support the massive natural floor will all provide tremendous mass. On average the entire layered floor & channels & sand slab will be 2.5 feet or 70 cm thick,  once heated or cooled, it will retain its temperature for a long time. Insulation will not allow for this stored energy within the 3 layered MASS to cool down by the ground.

I also do not have a luxury of 1 year waiting period and thus I will rent a machine to compact the sand. 

Previously I did not use this sand slab method and the process for me looked something like this:

1. Removing the shrubs and turf/grass with roots - 1 month
2. Dug out trenches and level the trenches - 2 weeks
3. Placed the row of tires or 2-3 layers of bags to get back to the original grade (level of the earth) 1 month
4. Due to my slow building the grass started to grow where I previously removed it and this took also another day all in all. 

As “fun” as it was it cost me one season, working half day. I was demotivated due to the slowness of this process and do not think I will ever repeat it. Trenching is great if you have the cash to hire a team and get a concrete truck to pour a foundation in a day. 

If you are wondering why the hell did use so long. I am used to design and computer work. I am also used to building with teams of students at my workshops or labourers at my dome site in South Africa.  This last build I was doing alone. This is what I realised: you can not compare your own strength levels with others who are used to digging and using their muscle power in outdoor conditions.

If you plan your build in advance and thus apply a sand slab one year prior the construction of foundations then this really gets FAST.  To spread and shape the sand will take you no more than 1 day with 2 people or a couple of hours with a machine ! WOW, I mean only ONE DAY VS a whole season, to get compacted earth, above grade , ready for foundations to be build upon!!! Because it is already above grade, in essence you are building the wall of your home.

The ondol floor or any other air channels I will be placing above on the actual sand slab.

Sand slab can also be used to level irregularities and even make a flat site, for your home, if you are on a slight slope.

Chunky coarse sand drains well and therefore no soil erosion should be observed even if you abandon your site for a few months to a year. If you are on a slope, please make sure you do a diversion swale “bump” to redirect any water coming down the hill from washing away your sand slab or constantly wet your foundations

FRENCH DRAIN AND TRENCHING 

Wet conditions on your building site: The best way to dry up a site is to use a trench around either your building site or your home as well as surrounding garden.

It is often practiced in our country and works exceptionally well. The water seeks the path of least resistance, so when it finds even just an open trench the water,  that’s stored in the hard earth, immediately starts seeping out of the soil, towards this trench. 

French drain works in the way. It is just slightly more advanced. Due to the higher cost, the French drain is usually placed just around the building site. It uses a perforated pipe and it is layered in a 1x1 foot trench filled with gravel which is lined and closed with Geotextile cloth. The cloth prevents earth from clogging up the gravel or the pipe. Due to the large air spaces between the gravel the water pulls in from the surrounding earth and enters the perforated pipe which then sends this water lower down . 

A gravel in a trench also works well, it is placed at the end of the plastic waterproofing roofing layer and makes sure that any water coming from above gets directed into this trench. The water that comes front outside of the home also gets into the trench. The correct slope of at least 2 degrees (2 cm over 100) channels the water away from the vicinity of the house or its foundations.

If you are on a dry site in the desert this might not be required at all. In any case you should always think of a way for water to exit your building site and avoid moisture from ponding up and seeping around and under your home. 

If you are on a slope building up a little swale “bump” in a C shape, convening towards the direction that the water is coming from will redirect the surface floods around your home site. 

If you are on a level site then making sure water has a way to exit fast and out.   Any indents in the earth will cause water ponding up and possibly even getting under your home. You #1 priority is to keep your house site dry!!!

If you have a low water table such as desert conditions then as I mentioned earlier consider digging your home with it’s foundation down, like we did in Siberia, for obvious reasons, previously described. This underground method will make a lot more sense once I you will see the entire build, in practice, in the near future.

To recap: a simple trench, is fastest and cheapest way that will LOWER the water table around your wet building site or your wet garden,  provided this water has somewhere lower to go away towards! A simple trench, after years, will silt up with earth falling inwards and you will need to hire a machine or clean it out yourself.

Gravel  in a trench around the building site, lined  and covered with Geotextile (or any cloth for that matter) will last much longer as cloth keeps the gravel clean from earth and silt.

Important to mention, wet garden is what breeds anaerobic bacteria (without air) and thus sun conditions are prone to rotting of the roots

UNINSULATED COMMON FOUNDATIONS

These will be explained in great detail in the video lesson that will follow this chapter.

The most common way of doing a foundation is to dig into the ground and use plastic to make sure that water does not enter the foundation and wick up the walls. This is exactly what we did in Brazil. 

In this warm climate we dug down 20-30 cm , placed rebar and pored stoney concrete mix over the rebar in a plastic lined trench. Another beauty of pouring concrete is that it is easy to level due to the water in the mix. Concrete has a way to cover up irregularities, and therefore the trench does not have to be absolutely perfect.

However you should still use a water leveller to make sure that one end of the foundation trench is not higher than the other end as this will result in too thin of a concrete foundation on one of the ends. A lo-tech way to check level between various points, is to use a water level. NB Make sure it has no bubbles in the pipe. 

It will be explained in the following video lesson next week.

In a dug down trench you can use tires and sandbags or even gravel and stones.

I do not have experience with gravel and stones and if you have an abundance of rocks, then do you research on this kind of foundation.

As I mentioned the tires use offcuts of plastic to stop the water wicking up and sandbags get covered up: the first two rows are covered in plastic and the 3rd row is also covered completely in plastic. The 3rd Row is what sticks out of the ground. This double coverage in plastic guarantees that the water will not enter you walls.

MISTAKES AND INPORVEMENTS

• A mistake that I’ve made with my trench foundation is that I dug it too deep. For every 10 cm too deep than necessary you need to build one extra row of bag, which is not a joke.
• In future if doing a trench I would make sure I insulate other under the tires or use volcanic rock such as pumice or scoria, which have insulation qualities, rammed into the tire. This should be done in cold climate as the cold earth will pull the warmth out of our MASS walls, causing our walls to pull the warmths out of our rooms. In warmer climates such as Taos this is not necessary due to the mean temperature of the earth being much warmer than in Canada or northern Europe.