Mounting lights on metal barn?

[FrogLick]

I'm just completing a barn with the usual ribbed metal siding. I want to mount lights on the gables but am not sure how to do so. The siding has a 1" high rib right in the midline where the flat base of the light would screw to the building. Is there a special type of T-box for this application or do I need to rig up some sort of shims or blocking to get a clean installation? Ideas or advice anyone?

 

[Bedlam]

I would just use some sort of shims on the box.
Maybe some PVC pipe cut off with a long enough screw through it.
I have used metal conduit and long drywall screws to space out pieced of metal on a wood stove protector.
But in this case id think the PVC would work well, Of cource your gonna get bee nests behind them too.So possibly a piece of wood cut to fit on the box ends, and painted would also do.
Hope this helps.

 

[Scooby074]

Just screw the light or box directly to the sheet metal. Thats how i always done it. I dont know of any special box to fit the contours of the sheet metal. Maybe there is a pantentable idea there. You could always spray foam around the back of the fixture to keep out the critters.

 

[mohrds]

Just screw the light or box directly to the sheet metal. Thats how i always done it. I dont know of any special box to fit the contours of the sheet metal. Maybe there is a pantentable idea there. You could always spray foam around the back of the fixture to keep out the critters.

I second screwing the box right to the sheet metal. Use a square box big enough to span across 2 ribs and fill the middle gap with foam to keep the bugs out. Put a thin layer of caulk over the foam to keep it from deteriorating from the sun.

You can also buy precut foam inserts to close up the rib gap. They should have them where you get the metal siding. I think they are called "End cap inserts" or something like that.

Doug

 

[Skerby]

i had the same problem installing my service entrance on my barn, so i shimmed the gaps w/ PT that i planned down.. then just silicone any holes for wire or channel (pvc) coming in/out.
basically the shim was just to get better suppor and prevent crushing the ribbed parts...

 

[QRTRHRS]

What kind of lights are you putting up? If you are installing spots, just get the round surface mount boxes with two ears for fastening. Use a threaded fitting on the back plug with caulking to seal it. If your placement does not have any wood behind the metal for the screws to catch, just use a pop rivet to secure the box to the building. Seal the screws/pop rivets too.

For something really large like a meter box, I use Uni-strut.

 

[FrogLick]

I'm putting up an old fashioned goose neck barn light on the gable end and the mounting base plate is flat while the steel has a 1" rib in the center; there is truss wood behind the steel to make a secure connection to. Electrical boxes are also flat on the back side so mounting the box to the surface of the steel is the same problem. I think what's going to be the solution is to make a 1" thick circular shim (same diameter as the base) with a groove for the rib, drill a hole through the shim, steel, and truss brace for wiring and make the elect. connection in a J-box on the inside. This will prevent crushing the rib, minimize more stand off, & close the gap on either side of the rib to prevent wasp nesting. I may use Unistrut for the meter box at the service entrance.

 

[radman1]

I would just mount the light to the right or left of the raised rib. I think your creating way too much work to have it perfectly centered over the rib and more potential for problems in the future. Mine is mounted just to the side and it is not really noticeable. I mount mine so that it attaches to part of the wood truss behind it. Drill a small hole in the joist to run the wire through. I use a round surface mount box with gasket between the box and metal. You can apply additional silicone if desired.

If you want the perfect look, try mounting 2 separate lights spread out over the front. Then you can go between the ribs.

 

[QRTRHRS]

If you want the perfect look, try mounting 2 separate lights spread out over the front. Then you can go between the ribs.

I think that even with the low wattage lights available these days that two would be excessive.

I just replaced my 175W mercury vapor light with a 65W high pressure sodium light. More than adequate.

My original light falls between the ribs. Have to look tomorrow when I go out to the barn to see if it is centered or not. Mine is right over the door rather than up at the peak so it may not be so noticable if it is off center.

 

[excelagator]

I put up a gooseneck barn dish-type light on our barn's gable end about a month ago. I had somewhat the same problem. I used a weather tight round housing. I used this due to putting a photoelectric eye on too. It had 2 ears to mount it. I did have to "bridge" the ribs of the sheetmetal. It worked well and is pretty solid. I did offset the light mounting due to the center would not work.

The light fixture could take a 300 watt flood. I installed a flood florescent.The Puts out 120 watts, but only draws 27 watts. I am somewhere around 5 amps drawing overall a night. The bulb is Feit PAR38 EcoBulb Flood. Menards has them and retail for only $8.

Dan