4x4 or 6x6 post?

I am going to explain this the best I can. If you have a deck, lets say 15ft by 15ft whitch is screened in with a roof over it do you need 6x6 posts or are your regular 4x4 posts ok. I am not sure when the change would need to occurr or if it depends of the weight or other factors. If anyone has any info it would be appreciated.

It would depend on many factors. Number of posts, spacing between, height of deck, etc.

Just curious… If this is your deck and it is built already, why ask now?

See pages 3-4 here:



This is not my deck although it is a very nice one and I would not mind if it was.:slight_smile: A contractor, or so he claims, asked me the other day and I told him I would let him know something.


Thanks for the info.

http://buildingcodes.jocogov.org/documents/Deck%20Book.pdf corrected link

support could be 2 x 4’s if spaced properly.
i don’t think your joist is going to span 15’ so you’re going to have at least three bearing points.
you may need diagonal bracing, too.

what you are supporting is the dead load (weight of deck) + the live load per local code + the snow load per your local code

just dodge the question like we are!