Originally Posted by stefman
I used a 1" aluminum tubing for my spacer. I mitered the 4 corners and had someone TIG weld it together. The welding job cost $40 alone but I feel it was well worth it as it will always fit any 14" fan. All in all it cost about $75 with material to make the spacer but it stiffens up the roof nicely and I have full head room in my trailer (I'm 6' 2") . David Tilston shows you how he did his with fiberglass tubing which is definitely another good way to go and cheaper(I believe). He even has links to the tubing. Good luck.
Never thought to use an aluminum spacer. Sounds like it works well. I have two trailers though and one of them has two vents. $150 for spacers on one trailer seems a bit much to me. Although I do have a brother in law who is a welder....
I think I am going to try the PVC boards and see where that gets me.