I am planning on building a house by myself a few years from now. For two reasons : I want to learn the skills, and to save money. I will do most of the work except the roofing and the plumbing. I estimate it will take 2 years.
So far I came up with this budget for a 2000 sqf structure (does not include land or paperwork) :
-5K for foundations
-5K for cob / straw bale walls, I'm planning to get the cob from the land which should be over 15 acres
-13K for the roof frame and the tiles provided I manage to make the tiles myself out of free clay from the soil
-10K for doors and windows
So that's 33K not factoring in the electrical and plumbing. The finishes should be plaster, how expensive can that be ? I don't want to use painting. Let's add an extra 10K for the finishes and renting the tools.
I will probably build all walls with cob, except the north wall. That one would be cob doubled with straw bale on the outside for insulation, so as to use the thermal mass to radiate solar heat back inside the house. The floor would be made of cob also. Thick cob walls should give the structure sufficient load bearing capacity.
The climate I will be building for is very dry, excessively sunny, moderate to warm temperatures during the day to close to zero at night, or below zero in winter.
Back to back plumbing is definitely a cost saver. I will not have septic, but a combination of incinerating toilets and a compost system. I have seen videos where people treat their grey or even their black water using plants.
Millwork I would buy that used. I don't need much of it, probably. The hardware could also be had used. I looked up doors and window prices, they don't seem that much expensive on home depot.
So is a 43K budget realistic, without plumbing and electrical ? Thanks for your help.
"and the tiles provided I manage to make the tiles myself out of free clay from the soil"
I can't speak for the cost of most materials (which varies drastically depending on what part of the world you are looking at, among other things), but this is a catch unless you have experience doing it. Even assuming the clay you find is good enough quality to make strong tiles, there is a lot of labor in forming all the tiles, drying them, and firing them. A very dry location is not likely to have the quantities of firewood needed to fire tiles without expense in money or long-haul labor. A kiln to fire the tiles takes work to build and experience to fire without destroying a large part of the wares. A very dry location can make do with unglazed softer tiles like a home operation is likely to produce, as long as you will never get the tiles wet and then frozen.
For a few other factors, why do you necessarily need a significant monetary expense for foundations? If there are stones available on your land, and easier if you don't need to go deep in the ground for frostproofing, you can make a good "rubble trench" foundation with no more manufactured materials than maybe drainpipes and filter fabric, and maybe you can do well without those in a dry climate.
You say you want a 2000 square foot home, but expect to build it by yourself. That is a huge amount of space for one or two people, and I would think about how much house you really need for the next few years. If planned well, you can build a small efficient house now and add to it when you need more, having a usable house all the while. Are you planning one floor or two? A big roof may make cooling harder, and a two-story house takes half the roof and gives more spaces sheltered from heat. It is really hard to give the right advice, including costs, when we don't know more specifically where you are looking at building. We don't need exact country, but a region will help inform appropriate materials and designs, and help give a handle on relative costs.
I just looked up how tiles are made, seems like a straightforward process except the firing. You're right that might be a challenge. I am eyeing the southwest around Utah/Colorado, I don't live there yet. It gets below freezing there so maybe I would have to frost proof the foundations. As of now I know little about foundations, as you can see I'm still researching. I know a 2000 sqf house is a huge task, however I have seen people using backhoes to mix the cob and build the walls at a faster pace. I will probably exert my skills by building a garage in which I could live first, then I would build the house, which I plan will have only one floor.
Why do you need 2000 sq ft? Are you planning on having more than 1 person living there? The smaller you can make the house (within reason), the cheaper and faster it will be to build, and the cheaper it will be to heat, cool, and maintain. In my experience, 600 sq ft is plenty of space for one person, and 800 is enough for two if they share a bed.
Foundation is way low, unless you are basically building directly on bedrock. And even then you need a stem wall (the boots to keep the cob out of soil moisture and rain splash) which has to be quite substantial.
I know someone that build a 2000 square ft cob home. They said never again. Next time was a small home and then simple workshops spaces.
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Re foundation costs - if you build a conventional concrete foundation, it will need to be much much wider than usual to serve as a base for the cob. In Colorado, there is serious winter even if it's dry (I suspect Utah is similar), and you will need real freeze protection for your foundation. A rubble trench can still work at little monetary cost, but it would take significant labor.
It sounds like you are considering substantial and sustained work with a backhoe, which means you would have to buy a secondhand one - renting would get prohibitive fast. Factor in the cost for that, and don't plan on resale value, as one you can afford may not last much longer than your use without major repairs (don't ask me how I know ).
Water is also something you need to consider carefully, as the water laws in the Southwest are totally different than elsewhere in the world, and you may not even be allowed to use water that is on your own land. If the specific climate of the area you move to is really dry enough to fit your description, this will be a serious issue for you.
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