Corrugated Metal Roof Rehab

[Gilford]

I have an old shed that was built in two sections where I house my tractor. The new section was built in 1949. I am guessing that when the new section was put on, the whole shed was re-sided and roofed because the corrugated metal roofing and siding all look to be matching. The roof has a good pitch to it, I am guessing 10-12 pitch. A couple of years ago, I took the time to attempt to seal the roof seams where the roof panels overlap. I also attempted to seal all of nail heads. These attempts were not a coating of the entire roof, but just focussed on the seams and nail heads. I took care of most of the bigger leaks, but I still have some leaks that I cannot find the origin of. Has anybody found a good roof coating that takes care of these hard to find leaks? I hate the thought of spending a lot of money to completely replace a metal roof that is still mostly good. I have seen advertisements for people that come in and spray some kind of rubber coating on the entire roof. Has anybody had this done, and about how much per square did it cost?

Any help is appreciated.

Thanks,

Gilford

 

[2manyrocks]

Is this roof installed on a solid underlayment so you can't see exactly where the leaks are or is it installed on wood strips that are spaced several inches apart?

I try to mark where the leaks are when it is raining and then take a closer look at the roof when it dries up.

Also helps to wire brush off any rust and dirt where leaks are suspected because sometimes cracks in the metal are covered over the rust and dirt.

 

[ToadHill]

I've had good success with the coating made for mobile homes. Tar with a aluminum tint, black when you open the container and drys silver.

 

[Gilford]

Is this roof installed on a solid underlayment so you can't see exactly where the leaks are or is it installed on wood strips that are spaced several inches apart?

I try to mark where the leaks are when it is raining and then take a closer look at the roof when it dries up.

Also helps to wire brush off any rust and dirt where leaks are suspected because sometimes cracks in the metal are covered over the rust and dirt.

On the newer side which is what I am most concerned with, the underlayment boards are placed pretty close to each other. I've tried to find where the water could be coming in based on where the water hits the floor, but I cannot see anything obvious.

 

[Gilford]

I've had good success with the coating made for mobile homes. Tar with a aluminum tint, black when you open the container and drys silver.

Has this stuff been able to seal up seams and nail heads for you? I have read the containers before, and they all say to seal any leaks before applying.

 

[mikim]

I've also used mobile home roofing -- it's thick enough to seal small holes without a problem -- but the stuff I used was gold in color then dried silver ---- and it ain't cheap so the gold color fit.

 

[Larry Jones]

The water is finding a hole and running down the underside of the roof. I would make sure non of the nails are in the valley of the corrogation. and if they are use some silicone sealer. Same with any holes I found, use a bit of the silicone.

 

[2manyrocks]

If I now understand it correctly, you're having trouble pinpointing the source because it may be running on the other side of the boards before it actually exits into the structure. So you basically have to try to imagine the path the water is taking to find the source of the leak.

I would suppose that a top coat would seal minor holes, but won't you get in the pattern of having to recoat periodically? Depending on the size of the roof, could run into $ over a period of time.

You're going to have to clean and prep the surface to apply a top coat. Before I went too much further, I'd at least take a stiff broom to it and inspect every nail. What I found with mine was several places where there were old nail holes --- in places where there shouldn't be any holes. Attempted bad repairs or what I cannot say. And then I found places where there were cracks from metal fatigue.

 

[Gilford]

Thank you all for your input. When it warms up in the spring I will have to take a closer look at things and weigh my options.

 

[skipmarcy]

If it were mine and the metal was still in good shape I think I would carefully pull the nails and replace with metal siding/roofing screws - the 1/4" hexhead with the metal/rubber washer. You can get the painted or unpainted and in different lengths. No more water leaks from the attachment points and much better wind strength. Also, you need to see if the lap joints of the metal are the "anti-siphoning" type. If not, you could raise the upper panel at the joint and run a bead of good silicone where they join while you were changing to screws. Would be a tedious job but would be a permanent fix.