Howdy guys, I have a 42'x36' Metal skinned on Metal beams/Purlins) hangar that was built about 25 years ago.
While putting in a mezzanine/loft I took down the Fiberglass batting that was installed on the bottom of the purlins (Normally they erect the metal frame and the purlins and then put the batting on TOP of the purlins and then the metal skin on top of that.). What I noticed is some water staining and areas on the purlins where there was rust developed from the moisture being trapped from leaks I guess.
We want to do this before we have the ceiling spray foamed. We removed the batting because we want to regain the head height between the purlins.
So, what to do about fixing it before I have the ceiling spray foamed with insulation. We pulled down the batting insulation because we want the headroom between the purlins instead of the batting hanging down lower than the purlins.
It appears from looking at the screws that were used to screw the metal skin that they may have been overdriven or with normal heating/cooling contracting and expanding that the rubber washers looked to have squished and deteriorated and that this may be causing some of the leaking. I have not actually been up on top of the roof (But looking at the skins on the door and sides of the hanger, I bet the roof is the same or worse).
Some thoughts are:
1. A set of hangar owners at the airport with newer (by 10-15 years) had someone come in and unscrew every screw part way, shoot a blob of RTV under the rubber washer and then screw it back down).
2. Someone suggested to install the next largest size rubber washer metal self tapping screw in every hole (IE: Remove screw, put in new larger screw). I'm not sure that oversizing is needed because screwing into the metal the threads should be ok. Where I have seen that suggested is metal roof on wood where the holding power may be compromised into the wood.
3. Just replace the existing screws with new screws and try not to overdrive them and squish out the rubber (or neoprene someone will point out) washers.
(Is it possible to get up on the roof and walk/kneel around? I don't know the gauge of the metal but I know the purlins are spaced at 48" apart from each other.
I think I'll try number 3 first on some of the walls/door to see how that works and if the threads in the metal framing is going to be ok with a new screw of the same size and see what works better a DRIVER or a drill with adjustable clutch.
Any other thoughts? I will try to call a metal building installer and see what their thoughts are.
Thanks!
Mark