mounting fixtures on corrugated metal

Status
Not open for further replies.
I've tried every method, and the only thing that's even halfway satisfactory are old-fashioned toggle bolts right through the steel. I compliment the toggles with 'fender' washers to close the outside face of the hole.

If you have access to the back side, only then can you consider running 'ordinary' screws into a backing piece.

If you have the lattitude in placing the fixture, you can run through the sheet metal and into the light-steel framing with Teks screws.
 
I apologize, my earlier answer was incomplete.

I should have also made clear that I much prefer mounting the fixture to bits of strut that bridges the ribs in the siding, with the strut anchored to the ribs with toggle bolts.

If "weatherproofing" is a concern, talk to someone who does kitchen hoods. They have some very nice compression-type fittings that will seal the wall where your pipe comes through.
 
renosteinke said:
I apologize, my earlier answer was incomplete.

I should have also made clear that I much prefer mounting the fixture to bits of strut that bridges the ribs in the siding, with the strut anchored to the ribs with toggle bolts.

If "weatherproofing" is a concern, talk to someone who does kitchen hoods. They have some very nice compression-type fittings that will seal the wall where your pipe comes through.
Click to expand...

shallow strut I take it?
 
I may be over simplifying this, or am not picturing the same thing but whats wrong with self taping screws? Wall pack are you talking about emer lights? to something like this
images
 
The metal siding is too thin for self tappers to hold for very long. You need something behind the siding.

Fender washers, 1900 blanks with a hole, strut all can work.

EMT or PVC cut to the same height as the ribs make good spacers if layout requiring fastening on a flat in the siding.
 
Yes, I use the shallow, or 'thin' strut.

I agree that self-tappers ("Teks") screws just won't hold.

I've tried pop rivets, including the 'nut' insert types, and failed.
I've tried the 'molly' anchors, but the sheet metal is too thin for the molly to reliably clamp firmly to it; those are really meant for drywall, it seems.
Masonry-type expanding anchors don't expand enough, and pull right through.
The various 'butterfly alternatives' - the ones that you hammer through, then a wing pivots out- don't work very well either.
Simple plastic screw anchors- nope! The sheetmetal slices them apart.

IF you can get to the back side, you can use large ("fender") washers and nuts. The problem is getting behind them. Even "open" buildings generally have insulation on the inside. You really don't want to slice open that vapor-barrier facing. Very often what you see on the inside is actually a different layer of sheet metal- with as much as 10" between it and the outer shell of the building.

So, it's time for the Unibit, some 3/8" or so holes, and real, traditional, 3/16" toggle bolts. Keeping the wings from spinning as you tighten them down is another reason to mount them on the ridges; the back side if the ridge is a 'valley' that traps the wings. (Naturally, there are different profiles to metal siding, so adapt as necessary).
 
Last edited:
We've always done well using the same type of sheet metal screws that are used to secure the sheet metal. They are about 2" long, self drilling, and usually have a rubber washer on them. 4 of those do a good job of securing the wall pack.
 
Status
Not open for further replies.
Top