Foundation
The foundation type you choose to build will depend on a few factors: your preference, your concrete contractors preference, and particular requirements of your land. There’s a ton of information out in the world already about foundations and the building science behind them so here I’ll simply talk about my two options. Two great resources are JLC Online & Green Building Advisor
The foundation was one of the trades I simply don’t and didn’t know a lot about. The best I could do here is go with a trusted contractor in the area and leave it to them to create something good. This is one of those areas when you’re building on your own you just have to let go and have faith you picked the right person to help
My 24x52’ ICF foundation cost $11,472.00 + $350.00 for the exterior peel & stick waterproof membrane
The two style I had to choose between were:
ICF crawl space / Insulated concrete forms
Monoslab / I would likely use EZ Slab Forms if I did this type
Benefits of each
ICF crawl space creates ‘free’ space for your HVAC equipment without having to create sq footage inside the home for the equipment. It’s also easy to run run plumbing + electric today and into the future. I personally like forced air HVAC (for the air movement in the home) and todays heat pumps are crazy efficient pulling heat out of freezing outside temps. Another subtle advantage is not needing a plumber to visit the job sit in between the foundation forms being laid and the actual concrete pouring. Today there’s little reason to use traditional concrete forms & then adding EPS foam insulation after. ICF forms are fantastic and the concrete team doesn’t need to return afterward to get their forms.
Advantage of Monoslab is slightly lower cost and not having to build decking or stairs to get into your home. The entry into the home can be flush with the ground. A disadvantage is that it’s more difficult to change or fix plumbing in the future. Another disadvantage of the Monoslab is finding a proper contractor that fully understands the building science of creating a frost proof foundation, it’s why I would spring for the EZ Slab Forms and be done.
An extra expense of the Monoslab foundation is needing to run hydronic floor heating, aka radiant flooring. I would budget $15,000 for that + the utility space to hold the boiler equipment. That extra expense can be offset by not needing to buy hardwood flooring and instead sealing the concrete as your finished surface. I do love concrete floors (a lovely design contrast) but I also love moving air! With an ICF crawl space you get both heating & AC in one.
Neither choice is the wrong one and both have their advantages
