Water and frost are the two forces most likely to damage a building from below, and the most useful protection is deciding well before you build.
What the books cover and what they do not
The books say little about structural foundations, so this article sticks to the principles they do establish and to widely accepted basics, and it points you to professionals for the rest. Foundation design depends on your soil, slope, climate and building type and should not be improvised.
Keep water away
The book's site-visit rule is that water should flow away from the building site. Observe drainage before you choose a spot, check flood plain maps and note signs of a high water table, such as willows and alders (see drainage planning). Gutters and downspouts should send roof water well clear of the walls.
Respect frost depth
The book says to find out the depth at which soil begins to freeze, typically about 1 to 4 feet (roughly 0.3 to 1.2 metres), and notes that this is something to research before you lay your foundation. It advises keeping water pipes below that depth or protecting them, and checking local building codes for the figure in your area.
Protect what runs through and around the foundation
- Keep water and drainage pipes below frost depth or properly insulated.
- Keep soil around the house sloping away from the walls.
- Avoid planting large trees very close to the building, as roots can affect the ground.
- Inspect after heavy rain and frost, and repair cracks or settling early.
Choose the type of structure with the ground in mind
The book notes that small homes can be built on foundations or on trailers, and that beginners often start small. Which suits you depends on regulations and the ground. See planning a small off-grid home.
The Choosing Your First Off-Grid Home guide sets the building in the context of the whole property. If you want a practical overview first, see Off Grid Survival for Beginners.