When a metal roof begins to leak most Indiana building owners don’t rush right out and have it replaced, they do the logical thing like try to have it repaired. Many business owners may even attempt to repair the metal roof themselves or have their in-house maintenance department try. But making the wrong kind of metal roof repairs can actually make the problem worse.
Avoid making your metal roof leaks worse with the wrong kind of repairs.
1. Trapping water behind a Pipe Flashing or HVAC curb
A very common place for metal roofs to leak is around pipe flashings and around the HVAC units. A very common repair method in Indiana is to apply more caulking, tar, or metal roof coating around the leaking flashing. Apply the right sealant to the right spots can in fact stop the leak but taking the more is better approach with the tar or sealant and your likely to create a water dam behind the flashing. Too much sealant around the flashing can cause water to pond behind the flashing making the leak worse. Avoid trapping water by not filling up the entire pan of the metal roof with new sealant.
Repair tip: Always leave a way for the water to flow around a flashing even if it means applying less sealant.
2. Taking the shot gun approach
You can usually tell if the person who attempted to repair the metal roof found the specific leak or if they only found the area that the leak is happening in by the way they apply sealants and coatings. The shotgun approach of hitting everything in an area may seem like a sensible idea but it can hurt you later down the road. It can be tricky to find some metal roof leaks but you’ll be even more confused if the leaks returns even after you covered everything in the area. Or if the shotgun repairs approach actually works and you successfully stop the leak you will never really know why and the next time you chase leaks on the same building you’ll be no better off
Repair tip: Be specific with you repairs even if it takes you several trips up to the roof and the process of elimination to get the leak stopped. Once you find the cause of the leak you can fix it permanently. You will also have insight as to whether this a leak from a bad roofing detail or installation problem that was repeated in other parts of the roof, whether it’s a material failure that you can be aware of in the future or if it was a onetime leak from a puncture or third party damage.
3. Caulking the Valley
Valleys can most certainly be areas that leak but always assuming it’s the valley and trying to caulk it up won't usually work. The reason that surface caulking doesn't last long on metal roofs is because the metal is constantly moving. The movement in the metal roofing quickly causes the caulking to break it seal to the metal. A second reason that surface caulking isn't the best idea in the valley on metal roofs is that once you begin to seal a valley you need to make sure its stays completely sealed from top to bottom from then on and that is almost impossible to do. If the seal breaks at some point in the valley and allows water to enter behind the caulking it may not be able to get back out. If the sealant on down the roof is holding it can cause water to build up behind it and force it into to home or building.
Repair tip: If you determine that it is in fact the valley that is leaking avoid sealing the entire thing and try to figure out which part of the valley is leaking. It may be a valley trim lap, missing or deteriorated butyl tape, screws that have gone bad or poor installation. Use the process of elimination to find leak, it takes more time but will benefit you in the long run.
4. Using the wrong coatings and sealants
On our service calls for metal roof repair we often find that whoever made a repair attempt actually found the right place to repair but they didn't use the right type of sealant or caulking to the repair didn't hold. Using the right type of metal roof sealant is just as important as finding the leaking screw or leaking lap. Not every kind of caulking will adhere to metal roofing and all the different types of paint used. Caulking that doesn't adhere can make it very difficult to find leaks in the future as at the caulking is still in place
Repair tip: Use caulking made specifically for metal roofs. You can find metal roof sealant at roofing supply houses and or buy it online but it’s not likely to be found in big box stores like Lowe’s, Home Depot, or Menard’s.