“In order for that thing to sit here you’re gonna need to put it on some piers as well as strap it down!”
I remember those words so well. The year was 2011 and the speaker in question was the building inspector who, despite the concrete pad our house already sat on, was not pleased with the trailer still being on its wheels and stabilizer jacks.
I turned to my wife and asked, “Now what?” In her infinite wisdom she calmly said to me: “Do what he says. Ask him who to call and just get it done.”
Thankfully those days are gone and the options are much more obvious thanks to Mr. Google and all of the other tiny housers that have traveled down a similar road. So what are these foundation options other than post-build, cinderblock piers? Glad you asked.
SLAB FOUNDATION. Now this will only work if you are building a small house. A house already built upon a trailer with wheels simply will not transfer over to a slab foundation. But if you are building a small house it is important to know that slab is a type of foundation consisting of a structural concrete slab poured directly on the ground. No accessible space exists in slab construction. They are most popular in areas of the United States that have a high water table. Slab foundations are popular in areas (i.e. the Southern United States) where there is a relatively high water table. (Water table refers to the depth in the soil at which you find water).
CRAWLSPACE FOUNDATION. Again, this type of foundation is best for a small house as a tiny house on a trailer has a natural crawspace despite its openness to the elements. A small house with a crawlspace has limited headroom but offers a bit of space between the soil and the bottom of the first floor of the house. This allows you to get to your utilities easier (electric, heating/air, etc) and is most popular in areas of the United States that have a heavy clay content.
BASEMENT FOUNDATION. A basement is an accessible space between the soil and the bottom of the first floor of a home. It has a lot more headroom and can even serve as an emergency hideout or a storage area. They are most popular in areas that have colder climates. I have often thought this would be a cool thing for a tiny house on wheels. Designed a bit like a mechanics pit you could drive your trailer over it, have stairs leading down, and have some sort of basement. Not all the kinks are worked out of the design including weather protection, security, etc. but it is a cool idea nonetheless.
TRAILER FOUNDATION. This is probably the most obvious and perhaps the only foundation available to true tiny housers. Equipped with axels and wheels this foundation allows your tiny house to be fully mobile. They are most commonly found on a house that is rolling down the Interstate.