Question Will 8 ft PVC sag over time?

You'd be better off with MDO, 6mm or 10mm alumalite, or even a banner..... than a wispy little 1/2" piece of PVC.

 

Seconding a truly rigid substrate- my go to would be ACM- at least a 6mm. Would there be any cross supports along the 8' side to stabilize it? If it's only meant to be temporary I would go with mesh banner.

 

Need more info....how high up? Attached to the posts how? If this is permanent, I would make it out of .080" or even 1/8" aluminum faces attached to 1/2" aluminum square tube, creating a box, then secured to 4" posts. Basically a really long post and panel sign.

 

I wouldn't use 1/2". 3/4" should work but you definitely need to account for it moving.

Cheapest 3/4" PVC you can buy is from Home Depot. Model # H190AWS13

 

At that size I would try to talk the customer into some sort of support rail. You're going to want to do a lot of screws or bolts as well to keep it affixed to the posts. Still would for sure suggest an ACM product over PVC- it really has a tendency to warp and gets brittle over time.

 

Oh well now that I see this just add an MDO piece and call it a day.

 

+1 for MDO

 

If you have 6mm acm drop pieces laying around use that... otherwise MDO