Over the past twelve years I have repaired or built on many different home foundations. So when it came time to build our cabin foundation I was a little surprised by how strongly I felt about one over another, and in the end surprised by the choice we ultimately ended up with. Our choice of going with a concrete slab foundation was mostly based on building cost and maintenance.
A basement foundation would have been great for installing mechanicals (HVAC, well pump, etc.), but no bones about it, this would have been the most expensive option. If you think about it, a basement is pretty much a concrete slab foundation (basement floor) combined with an extended crawl space foundation (concrete walls with a wooden subfloor). It is often said a basement is the cheapest space to build when building a house. I don’t necessarily agree or disagree with that statement, but want to point out each situation is different and should be evaluated. There is so much more to building a basement than just pouring some concrete walls and calling it a basement. Special care needs to be taken to waterproof this area, especially if it is to be used as living space. When I built my personal residence, I spent over $2000 on products such as Volclay Panels and Dryloc to ensure the basement was waterproof. There was just no way to justify all the additional cost of a basement foundation for a rental Log Cabin. And don’t forget the ongoing cost of heating and cooling the additional space that would probably never be remodeled anyways. Just not a good choice for the cabin.
Crawl Space Foundation
This option did not stay on the table very long because of previous experiences I’ve had working in crawl spaces. I have to say, laying on my back in a mud puddle on a cold January day, working on a waterline is NOT my idea of fun. However, I would almost choose the winter over the summer to do that work because of all the bugs and spiders that like to hide in the crawl space. It sure is hard to tell the good spiders (wolf spiders) apart from the bad (Brown Recluse) while crawling on your belly with a flashlight! Bugs aside, the crawl space foundation was the cheapest way to go. And it would have allowed me to change things around some, if I needed to down the road. However, the cost difference between a crawl space foundation and a concrete slab was around $1500, according to my estimate (see cost estimates – PDF or Excel) and just was not enough difference to look past my dislike for this foundation type.
Concrete Slab Foundation
As with the other options, the concrete slab foundation has it’s pros and cons, but overall I think it will be the best choice for a rental cabin. I really like the idea of not worrying too much about termites or rot, and with the drainage tile installed, water should not be a problem. A slab is pretty much indestructable, which is a great thing considering I’ll never really be sure what type of person I rented to until they are gone! Going with a slab foundation requires all the main plumbing to be mapped out before the floor is poured, but I pretty much had that already done. Building on a concrete slab will also give me a little more piece of mind about the weight of the cabin itself. Even thought I visited serveral cabins with double rim joist, I was always a little nervous about the load put upon them. In general, a concrete slab foundation should result in lower maintenance. I have a feeling one of the keys to running a successful cabin rental business will include doing all I can do reduce maintenance.