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.
Floor joist 2 x 10.
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.
1 psf lb f ft 2 47 88 n m 2.
But larger is not always better when builders are constructing a home or adding a room addition.
2 prime kiln dried southern yellow pine lumber meets high grading standards for strength and appearance and is easy to cut fasten and paint making this the best choice for many building projects.
Find 2 in x 10 in pressure treated lumber at lowe s today.
Dead load weight of structure and fixed loads 10 lbs ft 2.
Every piece of 2 in.
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.
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.
Common joist spacings for 2 by 10 joists and other dimensional lumber sizes are 12 16 and 24 inches.
2 x 8 joists spanning only 8 feet is more than enough.
2 grade of douglas fir are indicated below.
Maximum floor joist span for no.
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.
Joists that are closer together can support more weight which allows the joists to span a longer distance than joists spaced further apart.
Live load is weight of furniture wind snow and more.
Spaced o c species grade 30 lb ft 2.