Floor Joist 2 X 10 Or 2 X 8

Even when using the strongest wood to build joists for a deck that wood is still subject to the elements and can bend bow or warp with time.

Floor joist 2 x 10 or 2 x 8.

Must use ground contact pressure treated lumber where lumber is at risk for poor air circulation less than six inches from the ground or has poor or no water drainage below the structure. Scn smooth shank hdg connector nail 600 pack. When framing openings use header and trimmer joists. The extra two inches of vertical distance when a floor is framed with 2 x 10 joists rather than 2 x 12s can be quite important for example.

General rule of thumb is only cantilever 25 percent of the total length of the joist at a maximum some say you can go 33 percent and code does allow that. Steel joists offer a stronger straighter and potentially safer alternative to wood. Common sense tells you that large floor joists can carry more load and spacing joists closer together also increases the load bearing capacity of a floor. But larger is not always better when builders are constructing a home or adding a room addition.

Use an approved hanger or a 2 x 2 ledger strip on flush beams for spans greater than 12. This will give you a much stronger beam. For example in the joist span table below the highlighted cell shows that 2 x 8 southern yellow pine joists that have a grade of 2 and are spaced 24 apart can have a maximum span of 10 feet 3 inches 10 3 if designing for a live load of 40 lbs ft 2. However with this type of situation the heavier the better so you will have a very stable and secure platform with the use of 2 x 10 s.

A live load of 60 pounds per square foot demands more support and shorter spans. Spaced o c species grade 30 lb ft 2. I would use at least 2 2 x 8 sandwiched together if not 2 x 10 or 2 x 12. Depending on the length of the home and the number of floor joists the additional cost for the heavier floor joists may not be very substantial.

Treated lumber is critical to the performance and safety of an entire system or construction such as deck joists beams and ledger. Steel joists such as trex elevations are machine made making each joist an identical twin. 2 x 8 joists spanning only 8 feet is more than enough.