composite decking


  #1  
Old 08-07-03, 04:48 PM
paris401
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composite decking

hey guys... as i mentioned on a few of the previous threads over the last couple of months, we are building a fairly large deck and decided on weatherbest as the material.

our builder went 12''oc, doubling up every other joist. (overkill)

today i got to see it and it looks great, b u t .. i was somewhat suprised that on the top deck (some 25ft off the ground) there still is a little 'bounce' when walking on the deck. not a lot, but i noticed it..

just want to mention to others that might be considering weatherbest (not sure about other composites), think carefully about going 16''oc.

by the way ours is laid straight across, not on an angle.
 
  #2  
Old 08-08-03, 03:50 AM
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paris401,

Thanks for the info!
 
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Old 08-08-03, 09:57 AM
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What is your joist span?
 
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Old 08-08-03, 10:07 AM
paris401
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the distance between each beam/joist is 12'', and every other one is a double... . the width of the deck is 24 boards, or i guess thats 12ft
 
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Old 08-08-03, 07:31 PM
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I understand that your joists are 12" O.C., but how far did the builder span the JOISTS??? What did he use for joists?? What did he use for girders to support the joist? How far did he span the girders? And what did he use for posts to support the deck that is 25' above grade?

There's a lot more to "bounce" than just the deck boards!
 
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Old 08-08-03, 07:46 PM
paris401
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lefty.. now i understand.. i don't know the answers , but i will find out when i go to the house next week.

i do know that because of the 12'' oc + the doubling of every other joist, the builder went with larger diameter posts, and used a piece of steel for one of the spans.

exactly what was used, i will find out and let u know wed/thursday.

thanks
 
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Old 08-08-03, 10:23 PM
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Paris401,

I've walked across WB decks with the joists at 16" O.C., and I'VE never noticed any "bounce".

But your post sent up red flags!!

WHY would the builder put the joists at 12" O.C., AND THEN double every other joist???

I'm betting that SOMETHING is WAY overspanned!!!!
 
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Old 08-09-03, 04:11 AM
paris401
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lefty.. as i said i don't know the answers, but u can be sure i will get them.

the reasons for the 12'' oc + doubling, was i thought i was going with ecoboard- they recomend 12''oc, and that every other joist be doubled.

after investigating ecoboard, i decided against it, and went with weatherbest, but the framing was already done.
 
  #9  
Old 08-09-03, 05:45 AM
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when this 220 lb.'er walks around on my WB deck (12" on cent.), i dont notice any bounce. no doubling up on joists, and the deck is 15x19. something sounds strange. my deck height is apprx 4'.
 
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Old 08-09-03, 05:51 AM
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fatkid66,

If the joist spacing is fine, doubled on every other one, then the beam span and beam spacing is not up to par.

When you think about it, why would you double up every other joist if the beams were sized and spaced properly? A steel beam is fine but what is the "rest of the story"?

Has me wondering!
 
  #11  
Old 08-09-03, 03:25 PM
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Paris401,

I understand you can't look at the deck until next Wed. or Thurs. to see why this "bounce" is present. Also, I have never dealt with Ecoboard -- don't know wht they would call out a joist spacing pattern like you are talking about, but it would certainly make me think twice about using it!

Trex 2X6 calls for 20" max. joist spacing. 5/4 WB and Trex call for a max. spacing of 16". There are many other composites out there, and some will span just fine with the joists on 24" centers.

A 12" spacing tells me the decking is pretty limber. And doubling every other joist?

I don't know. I'll have to look around and see if I can find a dealer for it. THEN I can give you an opinion on the Ecoboard.

As for your "bounce", I was just trying to give you some ideas about other things that could cause it. It's certainly NOT the joist spacing!
 
 

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