While I find that new PT wood is in various stages of being soaked with
water and will shrink in width according to the amount of wetness.

I have found that composite materials do expand, particularly in length,
during summer and shrink in winter. I have some 20 foot lengths and they can
grow about a 1/4 inch in length over the winter measurements, and they will
actually "crawl" or move in one direction over a number of years, requiring
some leverage and banging to get them back in place. We do have extremes in
temperatures, winters down to zero, and summers up to 100 degrees which can
cause these problems.


"Thomas G. Marshall" . com
wrote in message news:w6mQj.4$r12.1@trndny03...

I've spoken to a number of people who have put composite decks in and they
followed the manufacturers suggestions carefully and ended up with boards
that just "seem" too far apart. A friend of mine has these large gaps
around his posts that I'm not particularly fond of.

And two of these people say they've never seen the boards expand nor
shrink the way the manufacturer warned. I'm not sure of the brands.

But this reminds me of something a construction guy told me once about PT
(I know, a different issue): "Don't ever listen to the advice about
keeping the boards a nail width apart....they will dry and shrink on their
own". The only reason I mention this is because I would like to know to
what degree such rules of thumb (PT or composite) are real, or just passed
along advice that never really applies.

For example, has anyone seen trouble with compostite decking boards placed
flush (say, in the summer)?

Thanks!