Using Steel Pipe To Hang a Room-Dividing Curtain: How Far Can It Span Without a Center Brace?

Question

My partner and I need to put up a room-dividing curtain in a room that’s 11’ across. The curtain will be fairly light-weight—just heavy enough to be opaque.

Unfortunately, it's an old apartment with a popcorn ceiling, so asbestos is a definite possibility. Therefore drilling into the ceiling to install braces for the curtain rod is something we'd like to avoid if possible.

We had a look at some galvanized steel pipe, and it seemed easily strong enough to span the room with only a good, strong brace at either end and none in the middle. My partner and I each held one end, and had a third party apply pressure to the center, and the pipe remained completely rigid.

I have two questions:

1. Is there some reason this won’t work? The common wisdom about curtains seems to be that you need to brace them every few feet at minimum, but I can’t find anything about how far a piece of steel pipe can span without a support.

2. Is there something we can coat the pipe with to make curtains slide over it with less friction? It definitely feels less slippery than traditional curtain rod material, and if we end up going this route we’d like to minimize the amount of drag, if possible.

Answer 1

What's the worst that happens? Assuming it's well supported at the ends, you will notice any sag, and can decide if you're OK with the amount. I've personally used a twelve foot tension rod before made out of super cheap steel to divide a room, and it worked just fine.

To smooth the running, you can paint the pipe. Just make sure to use glossy paint that is rated for use on galvanized steel, and let it get properly dry and hard before using it.

Or shortcut the whole thing and buy a long tension rod. Our favorite A to Z retailer has them.

Answer 2

For your span and the pipe's slenderness (I assume 1-1/2" schedule 40 at the heaviest), the design of your pipe would be governed by deflection. If you've already done the experiment, then you should be good. It's your space, so just remember your experiment and don't abuse the rod. (I once designed something similar for somebody else's space and accounted for a 45 pound wet laundry loading in the design.)

I expect that something like this will ultimately fail because of somebody deciding to hang some body weight on it. Just because. You want it to fail with ductility, bending a bunch while remaining attached to the walls/ceiling. This means that the connection strength is critical. You don't want dummy putting more and more weight on it until it suddenly rips out without warning and whacks somebody, ideally dummy himself, in the head.

You don't want an uncoated pipe with a cloth sliding across it. The finish is abrasive and even galvanized steel will stain the cloth. I'd give it a light sanding with 320 grit sandpaper, clean it with a degreaser (and don't subsequently get any oil from your skin on there), spray paint it with a metal primer, and spray paint it with a glossy topcoat designed for metal. The glossier the topcoat, the better cloth is going to slide on it.