cj wrote:
greetings, i am building a deck that will be 17 feet wide by 9 foot
deep. i will use 4x4's dug three feet into the ground, with a bag a
cement in each hole. my question is how much support(4x4)will i need for
the 17 foot span? obviously one 4x4 on each end but will one 4x4
centered be enough or should i break the 17 into thirds? so 4 columns
instead of three?

Other posted discussed spacing -- there are online sites that allow you
to estimate deflection based on joist size and support spacing. google
for "sagulator" or a post had the url a day or two ago.

How high off the ground? I'm partial to larger than 4x4 supports unless
it's very low for the extra lateral stability plus they give it a more
solid appearance...

--