I purchased an old building. The metal roof was installed by an amateur 4 years ago and it is leaking. I took a walk up on the roof and there are no obvious holes. The roof is installed on a concrete block building and has about a 6/12 pitch. He removed a few rows of blocks at one end of the building so that the roof drains into a gutter on one 28’ end of the 28’x80’ buidling. Apparently, the installer used some old flashing that is in between the layers of concrete block. I can see that the flashing was not screwed down in enough places as it is ripply. Because of where the flashing is installed, I cannot yet see what the installer did where the metal butts up against the concrete blocks.
Please comment on my plan:
- Unsrew and lift some of the flashing to see if the installer put any kind of sealant between the blocks and the edge of the metal roof. If he didn’t what sort of material should I use to prevent leakage at these seams?
- I will then reinstall the old flashing. In most cases, this flashing drops from in between the blocks at a 45 degree angle before it contacts the metal roof. I would plan to install at least twice as many screws as currently exist. I will then coat the seam with a sealant, recognizing that in some instances, there will be as much as a 1/4" gap to seal. Again, what sort of sealant should I use?
- To be safe, I will put sealant over every screw in the roof (the rubber under the screws seems to be OK, btw).
- Finally, at the edge of the roof where it drains, the installer left zero overhang. It appears that some of the water is wicking under the roof at this point. Would installation of a drip edge flashing be appropriate, or is there a better method to direct the water into the gutter?