How far apart should I space my floor joists?

I am building an ICF house and will be using 13 inch open floor joists. The longest span of floor joist is 18 feet between steel beams. The total width of that area comes out to 55 feet. One floor joist supplier recommends 16 inch centre spacing, and another recommends 19.2 inch centre. The sub floor will be 5/8 inch T&G plywood, with 1/2 inch plywood overtop of the 5/8 inch in the areas that will be ceramic (the rest of the house will be carpet, with hardwood hallways). What is your opinion on 16 inch versus 19.2 inch floor joist spacing?
Expert Answer:
I would go with 16 inch floor joist spacing. Although the manufacturer states that 19.2 inch is satisfactory I would still use 16. For the money you are saving at 19.2, it would be a more sturdy and stronger floor at 16 inch OC. Concerning the underlay, I would use 5/8 inch plywood under ceramic vs. 1/2 inch.
Answered By:

Custom Builder

Joe Princiotta - Princiotta Group
, Ottawa, ON,
Contact: 613-794-8222 ASK


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