Decks, Patios, Porches and Docks - deck beams and joists sizing..... again

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raggie man
06-11-03, 06:45 PM
Hi guys,

Thanks for the recommendations. I have reworked my deck plans and have now come up with the following.

Deck to remain 16' x 16', with ledger attached to cinder block structure. I have moved the beams, which will now be doubled up 2x8's, to 7' and 14' from the ledger, leaving 2' canted joists. I still plan on using 4 posts per beam but have increased the spacing from 4' to 4' 8" leaving 1' canted beams. I guess this will give me a total of 7' across 4' 8" post spacing and a bearing area of 33sq. ft. I will now also be setting the joists (16') on top of the beams as suggested.

My questions are:

a) What size ledger should I use. b) Will doubled up 2x8's be sufficient for the beams. c) Do you still recommend 16' joists (spanning 7' between beams) and if so what size should they be, or should I still use hangers and 8' joists on either side of the beam to make up the span moving back to the old beam spacing. d) Can joist hangers be hung with screws instead of nails. e) What is the best way to sandwich joists to make a beam ie screw/bolt pattern, glue ?

Appreciate your help,
Raggie Man


Doug Aleshire
06-11-03, 09:26 PM
Raggie Man,

a. Ledger should be same size as joists but you didn't mention size
b. I would say yes but 2x10's would be my choice
c. You can get 16" joists or get 10's and overlap the beams.
d. Hangers require nails as they have more shear strength - screws have more holding power but can break easily by lateral pressure
e. Beams can be attached to posts with bolts if lack of room under deck is an issue or use beam-post brackets. I never use glue as this is unnecessary. Proper nailing and bolting of beam ensures a solid structure.

Hope this helps!

lefty
06-11-03, 10:05 PM
Doug has given you great advise, as usual. My only question (or comment) would be with the joists. Doug is suggesting that EITHER a 16' joist OR using 2 - 10's and overlapping at the beam is fine. That's true. Either way will be just fine. But why by two 10' joists when one 16' will do just as well AND be less money?? If tranporting the material is a problem, have you asked your supplier about delivery? On a deck this size, and fairly close to the yard, I have never had to pay extra for delivery.