I am designing a new house. We will be using 12" engineered joists
with relatively short spans. The deflections on these alone calculate
to about 1/500 of the span. We will be using glued and screwed 3/4" ply
for the subfloor on top of that. I haven calculated that deflection,
but its got to be real small. Normally, the 3/4" hardwood floor would
run perpendicular to the joists. However, to do that would require a
framing direction that is much more expensive. Given that the floor is
so stiff, can we run the flooring parallel to the joists - or is that a
I am confused. I have seen hardwood flooring running 2 different
directions in a house depending on where the joist ran in a house. Is
there a reson why you want the flooring to run a certain direction?
Plywood does all kinds of crazy bowing and dipping. When you nail into
those valleys it may not be pretty. The flooring that runs
perpendicular to the joists is usually spanning a joist or 2 or 3. Of
course that depends on the wood you install. My house has engineered
joists on 19.2 inch centers. How they came up with that number in
Atalnta Ga. I'll never know.
I think the 19.2 inch centres is the whole number to allow increments of
exactly 8 ft for the subfloor. 5 x 19.2 = 96 in = 8 ft but still have a
wider spacing than 16in. I expect 24in spacing would result in the subfloor
needing to be increased in thickness too much.
The floors do not creak. I have been living in the house for nearly
seven years and the floors are silent. Just like the brand name on the
14" joists. The builder did not give a rats butt about cost. I wrote
all the checks for materials and labor. The floor joist size and
spacing was based on some computer program the joist vendor made. I
guess next time you come over for a visit you can stomp aroung the
house and tell me which areas have joists 19.2 on center and which has
joists 16" on center. ;-)
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.