I'm building a 20x30. Although based on John's plans, my foundation/floor setup is different as the designer didn't want to go with a single span and we're have a large beam holding up the roof (no ties). So I've got a beam down the middle of the floor sitting on 4"x4" nominal posts. On top of the beam I'll have 20' x 9.5" I-joists 16" oc. The perimeter foundation walls are fully-grouted 8" block with steel.
A few questions:
i) How should I do the center beam? It's three 7' spans and a 10' span (roughly). The drawings spec two 1.75x7.25 LVLs for the short spans and two 1.75x9.5 LVL for the long span. However, my supplier is suggesting 3.5" thick LVLs. Should I go for 7' lengths of the 3.5" thick LVL? Or e.g. a 7' and a 14' length of the 1.75" LVLs and build up a beam across all three short spans (keeping the joins over the posts)? I'll be building it alone so smaller lumber is better. I guess it's a trade of between load-bearing strength and lateral strength?
ii) With 9.5" I-joists spanning 9.5' at 16" oc, do I still need doubled-up joists under the bath and stove? Both will be cast iron.
iii) I've got a couple of point loads (something like 8000lb each). I've got the requisite footing, pier and post (4x6) underneath, but there's a doubled-up I-joist at that point (the posts holding up the main beam are in a wall). Is there a way of transferring that kind of load through an I-joist? Or should I just replace the doubled-up I-joist with a doubled-up LVL of the same depth (+ some extra blocking to take it out to 5.5" thick over the post)?
Thanks for any help...