Question:
What size H Beams are needed?
Background:
I’m building a deck over our walkout basement. The basement is only 7’ tall, so the deck beams need to be as short as possible with the fewest amount of support posts (hence the steel beams). Additionally, I’d like the steel H beams (2 total) to span 20’ between 2 support posts, with an overall beam length of 24’ (extending 2’ past each post). The 2 support beams will be parallel and spaced 10’ apart. On top of the beams will be 2x10x14 joists spaced 16” on center (with a 2’ cantilever on each side of the steel beams), so overall the deck is 14’ x 24’. I’m looking for the deck to hold a minimum of 50 pounds per sqft.
Best Answer
Per IRC, the minimum deck design live load is 40 psf, typical deck weight 10 psf, and deflection is limited to Span Length (L)/360. I will add another 10 psf misc. weight in the calculation below.
Note, W10 x 15 is slightly off, but considered acceptable.