I just got the quote from my lumber yard on my 19'x30' floor system. I'd heard that I-joists were better and not much more cost. I liked the idea of the lighter weight vs solid wood as I'm hoisting them up 12' in my existing 26' high ceiling shop. I'm studying all the information I can on installing I-joists as I've never worked with them.
The cost is $1984 for I-joists and 5"x12" LVL beams. The I-joists 16''OC span 19' clear and rest on LVL beams at each end. The 4- LVL's span 14' between the huge steel columns that hold up the 27' high roof. This is the specs from the I-joist supplier to meet 40 psf live load/15 psf dead load. This meets residential code for a floor full of people and furniture, all I'll ever need.
Then I priced 2x12 joists 20' long. I can make up my own beams from
4-2x12's glued and nailed. I'd put in posts so I'll only span 7' with the beams. This chart:
says I can span 19'11'' with 12''OC joists. All the charts for decks say I'm OK on joist span, but the made up beam spans all say 16' maximum joists can rest on the beams.This may include cantilever. If not I'll add more posts.
The price for 2x12's is $784! Way cheaper. I'm going to have a carpenter and the lumber yard manager(our best friend) look at the whole final plan.
I would rather use solid lumber. I know how to work with it. Framing the stair opening would be easier.
The main downside is I'm close to the maximum span and the floor may feel bouncy. As long as it meets code I don't care. I'll use it for minimal storage. I mainly want it for the ceiling. It's hard to heat and light a shop with 26' high ceilings. The other downside is I can't find 12" wide insulation batts so may have to cut 24", but to save $1200? No problem.
What would you do?