Decks, Patios, Porches and Docks - Proper installation of joists

Hi,

I'm currently in the process of building a deck and have a few questions in regards to hanging the joists. The wood we purchased is fair, but I've noticed that when we placed the joists in the hangers connected to the ledger/houseband, not all the boards were exactly level due to imperfections in the wood (crowning, the wood tapering at the end of the boards, etc.). I've haven't connected the joists to the header bands yet but they are close to where they need to be connected on the header. How do you go about making sure you have a consistent/level base to install the decking? We are using 2x10's on a deck that will be 15' deep.




Thanks,

Marty

You install the joists in the hangers so that at the ends they are flush with the rim joist (the board the hanget attaches to) and orient the 2X10 joists so that the crown is UP on all of them.

How severe the crown is will determine the best way to handle them. Assuming that you have a beam crossing under the joists at mid-span, you can usually have a person (or 2 if needed) sit on the joist to bring in in contact with the beam, then nail it to the beam (toe-nailed from both sides) Once you install the mid-span blocking between the joists (directly over the beam), nail that to the beam as well. That's usually all that's needed.

... Once you install the mid-span blocking between the joists (directly over the beam), nail that to the beam as well. That's usually all that's needed.

How can "mid-span" be directly over the beam?

I usually line up the joists (crown up like you said) with the top of the ledger board, then toe-nail them down to the beam, followed by lining them up with the top of the rim joist. It seems easier to push around the end of the joists, than work the middle after the ends are attached.

Thanks for the information. Once everything is in place, is there a way to compensate for any joists that are high? Also, I was planning on using hurricane ties; would that replace toenailing?

Also, I notice that most of the boards taper somewhat at the ends; meaning that the ends are about 1/8 to 1/4 smaller than the middle of the board. Do I still line up the ends with the top of the ledger and header? Although it would seem a hard task, is it ever necessary to plane boards down?



Thanks,

Marty

Marty, unless your joists are severely crowned, any slight uneveness shouldn't be noticed. Line up the joists crown up to see how bad they are. Anything less than 1/4" don't worry about it. Anything more than 1/2" crown I would use for something else (cut for blocking, steps or used as headers or doubled joists).

Ubob,

With a deck that is ledgered to the wall and projects 15', there have to be (or at least SHOULD be) two beams under the joists supporting them. 15' is too far for 2X10 joists to span without it.

I know that there are decks out there built that way -- I've seen a lot of them and have torn many down. But I can't rebuild them that way -- the plan checker won't approve it and the building inspector won't pass it.

Lefty,
I agree - 15' is too far a span for 2x10's on 16" centers. But that doesn't mean you need two beams to support a 15' deck.

I have designed, built, permitted, and had inspected and approved several decks that have withstood the test of time that are 15'+ , ledgered to the house, and supported by a single beam. What makes it work is that the span is 12' and the remainder is cantilevered. I use mid-span blocking (midway in the middle of the 12' span), or two rows of blocking dividing the span into 3 sections. The beam I used is 2 - 2x10's (2x12's in one case), mounted in notches on either side of 6x6 posts, and bolted thru. That approach to the beam also reduces the cantilever by about 4". Posts placed not more than 6' apart. Decking was 2x6 cedar laid on the diagonal.

Had you said you intended two beams, I would have understood why your blocking was directly above the beam. You assumed two beams, I assumed the span would be reduced by using a cantilever - neither of us explained ourselves at the start - sorry.

I actually have 2 beams(2x10's bolted together). One is at 6.5' and the other is 13'. This was suggested by the code enforcement officer. Joist spacing will be 12" o.c. to accomodate the Herringbone deck pattern that will be installed.
(4) posts were used for each beam. Beams were attached to posts with (2) piece post-to-beam caps from Simpson Strong-Tie.

martyc,

That's how I would be required to construct a deck with a 15' projection, other than my beams would have to be 4X6 or larger, and different Simpson brackets would have to be used.

But, in answer to your original question, place all of the joists 'crown up, and, like Wayne Mitchell said, anything around 1/4" is nothing to worry about but anything over 1/2" is reason to reject the board and use it for something else, like blocking.