How many deck screws?

Jeremy Hillary Boob, PhD · 09-18-2009, 01:51 PM

My deck surface is 2 x 6 redwood. On the part I'm currently working on these surface boards are 20' long, and they are supported about every 24" by the deck framing. I had to take up the deck surface to fix some problems that the previous owner created (long story...) and now I'm putting the deck surface back down. My question is, how many screws are required? I'm using 3" deckmate screws and I've put 2 on each end of each 2 x 6, but I'm wondering if it is OK to use just 1 screw at each of the interior points (as opposed to 2 screws at each and every point where the redwood attaches to the deck framing)? Previously, that's the way it was (mostly) done and the screws are expensive, but I want to be sure to do it correctly. Thanks.

**Termite** · 09-18-2009, 06:16 PM

Put two screws at each joist if you want to do it correctly.

bjbatlanta · 09-18-2009, 08:12 PM

Agreed, two is the correct way.....

rahfiki · 09-19-2009, 02:32 AM

I agree, 2 screws each joist. If you put one screw in the middle of the boards, you can end up with boards that twist on you, one in the middle will not stop a board from wanting to twist.

Just Bill · 09-19-2009, 07:01 AM

A bit late to suggest, but there several hidden deck systems that eliminate screws from the top of the boards.

itsreallyconc · 09-19-2009, 07:32 AM

did the 24" joist spacing cause or contribute to the original problem ? seems too wide for me but ' those guys got paid & they're gone ! ' as we used to say

believe they say ' can't see it from my house ! ' now

DUDE! · 09-19-2009, 07:49 AM

I'd also go with two, help keep the boards from curling, also, as someone pointed out to me, place the boards with the grain rings pointing down, again, to help keep them from curling.

Scuba_Dave · 09-19-2009, 08:43 AM

Do the deck boards bounce when you walk on them?
Now would be a good time to add more support

Jeremy Hillary Boob, PhD · 09-19-2009, 11:49 AM

Quote:

Originally Posted by Scuba_Dave

Do the deck boards bounce when you walk on them?
Now would be a good time to add more support

Thanks for all of the advice. I'll definitely bite the bullet (or is that the credit card?) and go with 2 screws everywhere.

As for the spacing... It's actually as wide as 27" in a couple of spots. The deck doesn't bounce, so the support in the vertical direction seems more than adequate (of course, that may have something to do with the fact that we're all lightweights in this house). However, there is some significant wobbling when I try to rock the deck from side to side. This part of the deck ranges from about 12' to 15' off the ground and it's got 2 support beams. The first support is about 8' from the house, and that's rock solid (a 4" x 12" beam with a solid foundation). Unfortunately, the second "beam" is not so great. It's out about 16' from the house and consists of a couple of 2" x 10" with some 4" x 4" angle bracing between---it was definitely an after-the-fact add-on to extend the deck. I plan on replacing that, but that won't happen until next summer at the earliest.

**Termite** · 09-19-2009, 01:20 PM

Yeah, 24"oc joists is insufficient for decks. There's no way you could do that by code in this area due to the design requirements for decks.

As for the side to side wobble, that's not caused by lack of joists. It is caused by lack of lateral resistance (posts). A good way to combat the racking that the deck is experiencing is to use treated 1x4's in a V pattern from corner to corner on the deck, and nail to the underside of each joist.

Jeremy Hillary Boob, PhD · 09-20-2009, 10:09 PM

Quote:

Originally Posted by thekctermite

Yeah, 24"oc joists is insufficient for decks. There's no way you could do that by code in this area due to the design requirements for decks.

As for the side to side wobble, that's not caused by lack of joists. It is caused by lack of lateral resistance (posts). A good way to combat the racking that the deck is experiencing is to use treated 1x4's in a V pattern from corner to corner on the deck, and nail to the underside of each joist.

At some point, I plan to double the number of joists, which will put them at about 12" OC, but it might be a while before I get to that. Thanks for the idea with the 1x4s. I will definitely do that.