Leaky metal building roof - any experts?

We moved last year and I am now blessed with a 50x50 steel building for a garage. Built appx 7 years ago, it is 14' on one end and slopes to 12' on the other, so not a steep slope. It is insulated and the insulation has a white plastic cover that you see from inside the shop.

It has 6 translucent panels and I have noticed drip marks beneath them in the past but until last week almost managed to convince myself it isn't a result of a leak. I read about metal buildings sweating and thought that maybe that was my issue.

We are in Los Angeles near the ocean so no rain but morning condensation is usual. We have had a lot of rain in the last week or so and I discovered that I had been lying and I really do have leaks. I can see corrosion marks around pretty much every screw inside on the roof joists. Also, every translucent panel has drip marks below them so they seem to be leaking too

The insulation runs between the roof panels and the joists. I am wondering if the insulation has compressed which has allowed the screw washers to loose and leak.

I haven't checked but I believe that the screws are in the valleys of the panels.

I thought about replacing the ~1800 screws but am thinking that a better solution might be cleaning the roof and slathering on some Henry's rubberized roof patch over the screws and around the edges of the translucent panels.

Any suggestions????

I am not an expert. Here's what I would do:

1. Climb up with a cordless drill and tighten every screw.
2. Drag hose up on roof and check for spot leaks.
3. Hit the leaky screws with the aerosol rubberized coating.

Robbie wrote: I am not an expert. Here's what I would do: 1. Climb up with a cordless drill and break off every third screw. Strip the rest. 2. Drag hose up on roof and check for spot leaks. 3. Hit the leaky screws with the aerosol rubberized coating.

Fixed that for you. :)

I am not an expert, but I spent 6 years manufacturing corrugated roofing.

Briefly, metal expands and contracts. the larger the piece of metal, the more pronounced. The expanding and contracting loosens screws. I'd go up there with a 1/4' ratchet, and gently tighten all screws, being careful to not snap them, and check the gaskets as you do so. You may end up caulking every one, as you say. If you go this route, don't go cheap. Solar Seal is the brand we used, and it stays flexible, while being tough. Finally, be careful! Those roofs are slick. A thick 2'X2' chunk of foam is your friend. If you want, special boots are made, and very effective.

The insulation is very thin, condensation blankets are about maybe a tenth of normal roof insulation there really isn't room to flatten.

I have rehabbed old roofs by re tightening the screws, replacing the screws that are very bad with thicker screws and silconing the berkeley out of each screw

Thanks for the replies guys. Really appreciate it. I'll order up some solar seal and some screws,rig up some fall protection and get to it.

wheelsmithy wrote: I am not an expert, but I spent 6 years manufacturing corrugated roofing. Briefly, metal expands and contracts. the larger the piece of metal, the more pronounced. The expanding and contracting loosens screws. I'd go up there with a 1/4' ratchet, and gently tighten all screws, being careful to not snap them, and check the gaskets as you do so. You may end up caulking every one, as you say. If you go this route, don't go cheap. Solar Seal is the brand we used, and it stays flexible, while being tough. Finally, be careful! Those roofs are slick. A thick 2'X2' chunk of foam is your friend. If you want, special boots are made, and very effective.

All of this. The other thing that I've seen happen (despite the fact that it's not supposed to) is that UV damages the washers and they're all junk. Before you gear up to make your initial attack I'd take the time to do an initial inspection and see if you need to replace all of them.

Also, back in the day nails with washers were used. They always back out but they can be replaced with modern screws.

My big thought and question is how tight should the screws be since it's not attaching the metal roof directly to the metal joist but has a squishy layer of insulation between??

jfryjfry wrote: My big thought and question is how tight should the screws be since it's not attaching the metal roof directly to the metal joist but has a squishy layer of insulation between??

Think of the rubber gasket like sway bar end links. You want to tighten til it fills out the bowl, but not beyond (like when the rubber starts splitting). If the rubber won't fill up the (upside down) attached washer, time to replace. Also, those skylites get brittle over time. caulking the top edge, and screw holes would be the most I'd recommend- obviously, stay off them.

It sound have the screws with washers and rubber washers on them. They do dry out and require re-torque. Most RV guys use clear RTV from GEOCIL as it is uv stabil and doesn't attract dust.rtv

In reply to 44Dwarf:

Good stuff but still attracts dust! Its the same stuff and cheaper if you dont by the "RV" branded one Amazon

Im guessing your going to find a lot of rotten washers. UV will kill them over time, especially in CA. They should just be snug, not push the washer out from under them snug.

Ya i don't get the RV branded stuff but i do get it from an RV guy who does mostly rv roofs... last couple of tubes cost me $6.50ea

Since I'm seeing corrosion around everts reeehwrenit comes through the joists on the inside, I feel like every screw is suspect. It will cost about $400 to get new ones. I checked the roof and there are some bad ones but most are still tight and look ok (although I think they're leaking because of the marks around each screw).

I know I need to get some good flexible sealer for the translucent panels and feel like I could spend less money and time by just cleaning the roof, getting a big tub of the sealer and putting a dollop on each screw.

Any reason not to just seal up each one??

jfryjfry wrote: Since I'm seeing corrosion around everts reeehwrenit comes through the joists on the inside, I feel like every screw is suspect. It will cost about $400 to get new ones. I checked the roof and there are some bad ones but most are still tight and look ok (although I think they're leaking because of the marks around each screw). I know I need to get some good flexible sealer for the translucent panels and feel like I could spend less money and time by just cleaning the roof, getting a big tub of the sealer and putting a dollop on each screw. Any reason not to just seal up each one??

No but you still want to tighten all the screws No matter what, otherwise you will have several hundred holes in your roof that may or may not leak someday

DONT STEP ON THE SKYLIGHT PANELS!!!

It's really easy to forget where you are and step through one. I know of 2 people that died that way.

You really should wear a harness.