ICF wofati

Just visited a guy with sunken passive greenhouse.  Truly inspiring!  His design to support the backfilled portion was corrugated metal backed by 4x4 posts.

He said that if he had it to do all over again, he'd do ICF all the way instead.

What are your thoughts?  Are ICF walls strong enough against soil pressure?

What are ICF's please?
Soil pressure can be dangerous, I believe each job may NEED TO BE DESIGNED, BUT THERE MAYBE A STARTING POINT.
Any wall resisting soil needs foundations with reinforcement bars, so its not a simple job.

Sure. If you choose the right thickness and design.

R Scott wrote:Sure. If you choose the right thickness and design.

Got any resources on how to choose that?

John C Daley wrote:What are ICF's please?

ICF stands for: Insulated Concrete Forms

From what I understand, you build the structure with hollow foam blocks that looks like this:

Image of ICF blocks, taken from nudura.com/

Then they get filled with concrete, either by hand or machine

Filling ICF wall with concrete. Image from businesswire.com

This makes a very sturdy (touted as being very earthquake and hurricane and tornado resistant) structure that is also very well insulated.  I'm not sure how much the foam bricks and concrete off-gas, or their ecological footprint. But, I'm really tempted to make our cellar out of this stuff, if we ever get around to making said cellar!

I imagine the space has reinforcement bars set according to the needs of the wall.
I will look.
Also, I dont think concrete off-gasses, where as the foam may.
This is a link to reinforcement details rebar-explained-a-comprehensive-guide-to-rebar-in-icfs/

K Eilander wrote:

R Scott wrote:Sure. If you choose the right thickness and design.

Got any resources on how to choose that?

Local building code, universal building code, icf manufacturer’s websites.

Keep in mind a sunken greenhouse might have to be stronger than a basement the same size. Many basements rely on the floor system to brace them, some even require the floor be in place before backfilling.  Larger newer earthships have buttresses to reinforce long straight walls. Most new homes don’t have a long straight wall just for architectural eye appeal, the corners add strength.

I wanted a wofati, but wife insisted she wanted a more conventional house, and where we bought land apparently the soil has too much movement during wet and dry extremes. So, we are building ICF, metal roof and siding, on a slab with radiant heating in the floor. In a relationship one makes compromises…

Anyways, it’s been a journey so far. The pictures are of our house this summer, I thought those curious about ICF might find them of interest. I’ve done the best I could to design it to be economical to operate long term with the in floor heat, will have a space for a wood stove or RMH in the living room. 85 tons of concrete in the footers, slab and walls should make for a good flywheel. I chose the most efficient attic and gable fan I could find so no plans on having AC. If needed we can consider a mini split later, but ceilings will be 9’ in the outer two thirds and the middle third is vaulted to about 14’. The patio was an afterthought, but the house is 44x40’ and it adds 15x44’.

With the metal roof at a 6/12 pitch and gutters running the length on both sides to one end we plan to catch as much water as possible in either tanks or cisterns like the local Amish do. Didn’t see any place under building to post, but thought this thread had folks interested so I wanted to add some pics!

Leif