Building a Basement

[VannL]

Has anyone tried this before?

I have an idea, but wanted to see what has been done by others first.

Specs: 20 x 34 full basement, with center supports for center beam.

[Squirl]

I will repost this here.

Have you decided what you want your basement walls to be made of?  (wood, concrete, block, stone)

[VannL]

I would prefer concrete or block. Just something that will last.

[UK4X4]

Mine is 26 x 36 long with a beam down the middle on both floors
Glulam supporting on the first floor and an LVL beneath the ground floor
2 steel adjustables in the crawl space and two logs on adjustables on the first floor

I was getting close to max height for the HOA, so 16 or 20" I-joists were out

[Squirl]

I have not.  I built a crawlspace.  I didn't want to have to worry about flooding/water problems.
http://countryplans.com/smf/index.php?topic=10998.msg140857#msg140857

It isn't that different.  You will have to pour some type of floor in the center, reinforce depending upon depth, and probably should water proof the walls.
That is another reason I didn't do a basement, I would have had to hire someone to work with for the slab pour rather than doing it alone.
I had lived in a place with the basement slabs poured in 8x8 foot sections, which might be doable alone.

The walls and footings aren't that difficult.  The walls are dependent on soil type and depth.  The footings are based on soil bearing capacity and stories.
Block wall requirements.
http://publicecodes.citation.com/icod/irc/2009/icod_irc_2009_4_sec004_par001.htm
Concrete wall requirements.
http://publicecodes.citation.com/icod/irc/2009/icod_irc_2009_4_sec004_par003.htm
Footing Requirements.
http://publicecodes.citation.com/icod/irc/2009/icod_irc_2009_4_sec003.htm