My barn is 40'x56'. I plan on boxing in a room on one of the gable ends. The room is going to be 16'x40. Instead of pouring cement in that are I would like to run floor joists instead. I plan on using 11'' I joists 16" on center. My question is how do I build the interior wall/foundation. I thought about constuction a beam as you would for a deck the 40' length for the joists to rest on. Am I on the right track for thinking this way? Any pics or help would be great! Thanks. -MATT
Floor joist for bonus room?
- Thread starter matt60j
- Start date
rieferman
Well-known member
What's your reasoning for doing the joists method instead of concrete?
rieferman
Well-known member
The reason I was asking is that by the time you buy the wood, and I think you'd need a pretty serious vapor barrier (else wood will rot, mold issues etc.), and the materials and effort to hold the joists... it's not going to be cheap going that route either. For a 16 foot width, and a bunch of buddies, I think you'd be able to finish the concrete yourself to save $$.
In any case, what I'd do if determined to go the route you're mentioning would be to basically build a deck using concrete tubular forms placed at proper distances. I'd want to seal moisture and critters out really well before putting the subfloor on.
edit: though not nearly as stable, there are also pre-cast concrete blocks that are formed to accept 2 by material or 4 by material. I believe they're used for sheds frequently. With these, in my opinion, you'd still want it sitting on a level, compacted gravel base. But, I'd be wary of this solution because for as big of a space that you're mentioning, and for as much effort as you'll be putting in, it'd be a bummer to have it not last as well as you'd want.
In any case, what I'd do if determined to go the route you're mentioning would be to basically build a deck using concrete tubular forms placed at proper distances. I'd want to seal moisture and critters out really well before putting the subfloor on.
edit: though not nearly as stable, there are also pre-cast concrete blocks that are formed to accept 2 by material or 4 by material. I believe they're used for sheds frequently. With these, in my opinion, you'd still want it sitting on a level, compacted gravel base. But, I'd be wary of this solution because for as big of a space that you're mentioning, and for as much effort as you'll be putting in, it'd be a bummer to have it not last as well as you'd want.
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Kevin54
MEMBER EMERITUS
You will probably need a rim joist out of standard dimensional lumber then put the "I" joist to it with hanger. But I'm with rieferman on this.....of all of the lumber for the joist, the flooring, etc. I would think it t be more cost effective for concrete. Plust the added fact that any moisture coming in through the ground will affect the lumber unless you have enough air space between the ground and wood. That being said, to build a wall you should have a proper concrete footing to build on unless you want to build everything like the deck on the back of the house, then build a wall on top of that. 
Not saying it can't be done, but personally I think concrete wold suit you better. Are you in an area that has termites (which almost everyplace does) or a lot of moisture. If so, you may want to look into all treated lumber for your joist needs.
Not saying it can't be done, but personally I think concrete wold suit you better. Are you in an area that has termites (which almost everyplace does) or a lot of moisture. If so, you may want to look into all treated lumber for your joist needs.