Replies

1. 
   xxPaulCPxx | May 06, 2011 07:38pm | #1

   What if you ran the Trex perpendicular to your existing 2x6 PT?  You get the stability of the wood, along with the wear of the Trex.

2. 
   Piffin | May 06, 2011 08:19pm | #2

   IPE` has the integrity to handle that span

1. 
   calvin | May 06, 2011 10:11pm | #3

   Paul

   There was a prior (years) post where the same alternative was mentioned-laying over the existing pt. decking.  Seems that some mentioned that as a bad idea.

   Trapped moisture was one reason.  I know Trex advised a ventilated frame below.  What's your thoughts now?

1. 
   DanH | May 06, 2011 10:16pm | #4

   One problem with the scheme is that it throws off the deck height.  Not important in some cases, but it can mess up step rises in others.

2. 
   DanH | May 06, 2011 10:18pm | #5

   Several years ago I recall seeing a product that was sold for overlaying.  It was maybe 3/4" thick and with an open back that would provide some airflow.  But I'm sure it would still promote rot in many climates.

1. 
   calvin | May 07, 2011 12:23am | #6

   And now.......

   I just read of an overlay product recently.  Sorry I didn't pursue the notification.

   Absolutely no help on this one.

3. 
   Piffin | May 07, 2011 06:59am | #7

   I would definitely NOT overlay materials. That causes all sorts of problems .

   I was suggesting an alternative of using IPE` because it helps avoid that problem and any need to reframe to 16" OC. Didn't notice that someone else had mentioned IPE`

1. 
   calvin | May 07, 2011 08:19am | #8

   Sorry

   You misunderstood my question.  I was referring to the suggestion of overlaying trex perpendicular to the old PT decking and wanted your opinion on that post (just previous to your post on ipe'. 

   thanks.

1. 
   Piffin | May 07, 2011 06:36pm | #9

   I C

   water gets trapped bteen layers like that and mold, smells, and rot ensues.

   trex and the other co,posites recomend clear ventilation under and over. I saked  awood scientist what that means once. He siad at least 18" under a deck.

   I just moved a "temporary" step at a door entry made with Trex decking. It was a simple 2x8 PT frame and trex decking.about 4' wide, 16" deep and 2x8 frame up.

   The bottoms of the trex was blossoming white mushroom type stuff

3. 
   ceb | May 08, 2011 05:32pm | #10

   Thank you

   I was pretty sure that composite over the decking was a bad idea, thanks for the confirmation. As for 24" centers looks like i have some structure to play with

   Thanks again

1. 
   Piffin | May 08, 2011 10:19pm | #11

   You do not need to change structure if you use IPE or use 2x6 decking

4. 
   ceb | May 12, 2011 10:14am | #12

   Agreed, can keep the structure if I use IPE or 2x6