Tiny House Foundation Ideas

Hey all! I'm a new here to Permies, and new to Permaculture in general. I was hoping I could get some opinions or thoughts on what I could use as a cost-effective foundation for a 14x24 wood frame tiny house. The frame is being built off-site and transported to our property, but we need to have the area levelled and a foundation ready to go. The builder has said that previous clients have done cement blocks that the pier posts can sit on, but I was wondering if there were any other thoughts out there. Not sure if patio slabs would be sturdy enough to take the weight of something like that or not.

Thanks for your help!!

solid patio slabs are ok.
The advantage of them is they are easily moved while you are leveling them across the site.
Create a pile in the shape of a pyramid to spread the load on the ground.
If you are putting them on filled ground, pound the soil firmly to reduce sinking.
Get a supply of wedges for the delivery day so the building can be levelled easily on the day.

Thanks! We were thinking of possibly doubling up on slabs and slapping some wet concrete between them to bind and let cure. The thought was to have something a bit thicker to take the weight of the structure but I'm not sure if that would be necessary with a structure this small.

I think you are thinking of overkill.
As a Civil Engineer I need to remind you 'concrete' has aggregate [stones] and they would be trouble for you.
Maybe some loose dry sand  but if the blocks are straight you should be ok.
Doubling them up does not made them stronger.
Increasing the area of the stack on the ground helps reduce the load per square foot on the ground.
Sometimes that is not an issue.
Have wedges as mentioned and also small bits of lumber that will not rot, IE 4x2, 4x11/2, 3x 3/4 say 6 inches long for packers.
Think about space under so you can get under and insulate etc.

Okay awesome. Yeah, the builder advised that the crawl space is typically something like 2 feet and is skirted for insulation and protection from elements. I think he mentioned something like a plastic drop sheet to contain moisture as well.

Okay, that's great, thank you so much!

Yes, you want a couple of feet at minimum of space under the floor, both for plumbing etc. maintenance access and to keep ground moisture from getting to the floor framing. Patio blocks under common concrete blocks may be good to spread the load over more ground to minimize sinking. How is the frame going to be placed onto the piers? A crane, or something else? You need to know where installation clearances under the frame will be needed, if any.

How level is your building site? Depending on how that compares with plumbing locations, you might be able to have the floor close to the high corner of the ground and still have accessibility where needed. Digging out some of the interior *while still having the surface slope to drain away* could get your floor closer to ground level to minimize steps.

Brad - you haven't mentioned, so I'd just like to make sure you've considered your geology/weather patterns etc?

I live in an earthquake zone, and it doesn't take that much to prevent a shelter from shifting off its foundation - and you can read that both ways! Not much for it to happen, and not much to prevent it! The last shed I built, I just hammered stakes into the ground and tied the legs to them with  wire, but it was just a 5'x10 shed - enough that reasonable winds can't tip it, and an earthquake short of the big one, won't shift it.

Similarly storms have been getting more active, and a tornado that would just take a roof off a secure home, may pick up and toss the whole house if it's not tied down. Mobile parks in some places require the homes to have "anchors" - again, it doesn't have to be complicated, just strong and in appropriate places.

This is a spot where "The Code" isn't necessarily your friend - housing codes in BC only care about people getting out safely, not still having a home to come back to. I want something on my land to still be safe to live in after shit happens (and we didn't build the house so all bets are off there!), so I'm much fussier than I was 20 years ago when I didn't know better!

Hey! I'm not 100% sure how the installation will be done but I could imagine a crane would be the most logical method. There is a slight slope from South to north on the property, so factoring a path for water is definitely something to consider.  Thanks so much for the info! I like the idea of working smarter, not harder!

That's a good point! I don't think we've got a lot of risk in the earthquake department, we're building inland in New Brunswick, so not commonly known for earthquakes. Doesn't mean that it's not something to consider to have good ties.

Thanks for the advice!

Has anyone used Ground Screws before?  I've been thinking about using them as foundation for a smaller future project.

They are excellent bits of gear.
Some are driven deep with machines.

We dug down 2 feet, filled with rock, then poured a footing. The pour is not required, you can simply build upon the rock surface.

Fwiw, I have not built a home of any size, but I've worked on a lot of them.
The prospect of a two foot tall crawl space gives me pause.
Its not that you can't work in such a crawl space, it more like you will hate it.
I say make it 3 feet , keeping in mind that plumbing , insulation and hvac ducts are liable to occupied some of that space.
The thinest block wall will make the best pest resistant skirting.
The thinest slab will keep out pests, protect your plastic, give you a better surface to work on, and potentially a place to store things.

Good point William.
Its nice to be able to actually move a bit while under a house.

Personally, 3 ft is a minimum - 4 feet is soooo.... much better, and I'm pretty short. At 3 feet you still mostly have to crawl which is hard on the knees. At 4 ft, many people can bend over and have their knees only partially bent.

Jay, you have a good point, that is another of the reasons for the thin slab.
With a slab, a creeper ,dolly or other wheeled device can be used to roll around, with dirt, not so much.

4 feet is open enough that  it won't invite animals to make a den, so maybe skip the skirting and the slab, box any plumbing etc into a purpose built chase, and insulate the hell out of everything.