cowtown ag02 said:
62- that makes sense in your example to excavate the additional space and make a larger living area. In my example, I just don't know how the costs would shake out on excavating the entire footprint of the main house to only have a smaller basement.
I guess my question is if you have a partial basement (which from additional research online I think it is what the basement is called that does not cover the entire first floor footprint of the house), is what type of foundation can be used on the additional main floor of the house? The one poster above indicated that it would probably have to be pier & beam with a crawl space. Could a slab on grade be used for the other portions of the house or is that just too complicated because I assume the portion over the top of the basement has to be wood floor joist and making the tie-in with the concrete slab would be awkward plus the issues mentioned above with differential movement.
Thanks again for all the input, very helpful in planning.
yeh for a partial basement (again, in CO), the 4 basement concrete walls are on continuous footings (even your 'walk out' has a 4th concrete wall, it just doesn't come above grade. It's 2' tall). Behind your back wall, the crawl space begins, and house above is on pier and beam.
You say "excavate the entire footprint of the main house to only have a smaller basement." that doesn't really make sense.
If you excavated all 4k sf, you might choose to only 'finish' 1000 sf., is that what you mean? Your remaining 3000sf is still there, and it is concrete floor, concrete walls, and exposed beams above. It is simply unfinished. It's not like it's just a dirt hole. It is how every basement starts. You could decide to finish more square footage at a later date. This is the beauty of excavating it to begin with. It costs roughly $30/sf to 'finish' it into basic livable space. With a crawl space, it is a major undertaking to convert it into livable space, likely way more than the initial cost to excavate it and include it in the basement.
It is very common to leave a portion of a fully excavated basement unfinished here as well. You put the furnace/water heater in there, and generally just use it for storage. A ranch home with a large footprint (say, 2500sf), will generally have 1700-2000sf of finished basement, and 500-700 of it remain unfinished.