Replies

1. Expert Member
   Akos | Jan 12, 2023 12:57pm | #1

   If you already have the basement, I would go for a crawlspace.

   The extra cost of floor joists is offset by not needing infill and sub slab insulation. Plus you'll end up with warmer floors and a way easier way to run mechanicals plumbing and electrical. Keep in mind that a crawlsapce is essentially a mini basement, so it needs to be treated the same. Insulation on the walls and conditioned air supply.

   Crawlspaces also make for a great long term storage where items go to die before being thrown out.

1. 
   aunsafe2015 | Jan 12, 2023 02:13pm | #2

   "where items go to die before being thrown out"

   Hah hah. The trash can before the trash can, so to speak.

2. Expert Member
   BILL WICHERS | Jan 12, 2023 03:17pm | #3

   Crawlspaces also permit for future maintenance issues, so something like a leak in a water pipe is a minor repair instead of the *major* rework that would be needed if that pipe were under a slab.

   Personally, I prefer to go with a full basement if you have the option, since you can put mechanicals down there and also store stuff in a more accessible space. If you're already excavating for a crawl space, going a little deeper to get a full basement isn't usually hugely more expensive -- and the construction part is pretty much the same, just with higher walls.

   Either way, if you go with a basement or a crawl space, insulate the walls, not the underside of the floor. Ideally you would do this with rigid foam on the exterior of the masonry foundation walls.

   Bill

1. Expert Member
   MALCOLM TAYLOR | Jan 12, 2023 04:20pm | #5

   Bill,

   "Crawlspaces also permit for future maintenance issues, so something like a leak in a water pipe is a minor repair instead of the *major* rework"

   Having spent the best part of a day tearing out and replacing half the t&g ceiling in our dining room to get at a leak, got me thinking about what the most flexible house would look like.

   Building on a crawlspace with a trussed roof goes a long way. Having services centralized and exposed in a mechanical would be nice too. Even using a suspended ceiling system below a second floor would make changes or repairs a lot easier.

3. Expert Member
   Michael Maines | Jan 12, 2023 04:15pm | #4

   I prefer slabs when possible. Less material, reduced risk of moisture-related problems, usually lower cost. Ideally with a concrete-free slab but that's not always practical. The main drawback in a situation like yours is the amount of interior fill required. If you have to bring in a lot of it, you might be better off with a crawlspace.

4. 
   bauchin | Jan 13, 2023 07:33am | #6

   Hi all . . . thanks so much for the insights and feedback. After talking with my structural engineer and reviewing everyone's feedback, I am going to pursue the crawlspace/basement option and, per your collective advice, detail the walls as a basement. My structural suggested that I draw it as a full basement given that we don't know the extent of ledge or its removability and we make adjustments after excavation reveals the extent of ledge. We can then decide where and how best to create/insulate the crawl space. The two factors that tipped me in this direction were the "warmer wood framed floors" and the "plumbing access" in the crawl space for future maintenance/reconfiguration. Thanks all for your helpful feedback

5. 
   walta100 | Jan 13, 2023 11:59am | #7

   I think living on a slab is hard. It is hard on your back and your feet the imperceptible bounce in the joists makes a huge comfort difference.

   Note a large excavator with a jack hammer often can remove the ledge rather quickly consider asking for a bid.

   Walta