The trex will never rot though,so bit the bullet on that cost.
True...But - I have an 1800 sq. ft. deck attached to my house, and I installed it. It is made from Timbertech which - like Trex is made from recycled plastics and other material ( there are several name brands - but all are recycled plastics mixed with wood fiber ) - but it *does* have the ability to warp....so - really anchor it well and attach it more often than you would if you were building with pressure treated wood. And - it splits easier than wood near edges and ends - *pre drill those especially*...so pre-drill all holes if using typical bugle head deck screws. There are special 2 thread pattern screws - but the head is very small....and can pull thru if you set them too deep. I would recommend typical deck screws with a washer under the head for the best option- balancing strength/cost/durability. Nails are out of the question, as this material does not "grip" a nail, and they will work out on you with a little time.
Hope that helps Spuds, keep us posted. This looks like a nice project!
T
Thanks Tim,Appreciated and Agreed.
I have a buddy who builds decks advising me,and all you said is what he said,you a builder too?And the holes have to be drilled deeper than I thought,I screwed three right thru the sides on first try,they just went sideways after started screwing in,odd material that trex.I got a makita drill thing that makes nice countersinks,and using stainless steel screws that he advised.
When the hoops are secured after being set in ground that will help keep trex straight too.And a little warping wont matter,I get lots of free leeway on that in this project,nothing has to be perfectly square or such,just close enough for gubbmint work.But they will get staked every 24 inches.Hoops will be set 24 OC,way over building on that but why not,cost isnt much more at all.And we get snow,not so worried about hoop collapse as strain on greenhouse cover.Its going to be plenty strong,and luckily in this little valley that winds are cut in half,so major winds are just heavy blows for us.
Ive done hydro before,but chemicals were a pain,bud down the street started hydro and shifting to aqua system too.