Few Roofing Products use the resilience, strength, and performance of metal roofing. That being stated metal roofs aren’t indestructible and they can leakage. Here are 5 typical factors even properly installed metal roofs can leak.
Metal roofing screws
Roofing screws are responsible for most of leakages on metal roofings. Metal roofing screws seal water out by compressing a rubber washer at the base of the screw head. When the screw is driven into the metal roofing panel the rubber washer forms a” gasket” in between the roofing panel and the screw head. It sounds basic enough but a number of things can go wrong like under driving screws, over driving screws, driving screws at the wrong angle and screws that missed the framing member.
Over driven screws: In an effort to ensure a tight seal in between the metal roofing and the screw head numerous roofing companies will over drive the screw. The unnecessary torque breaks the rubber washer and tends to spin it out to the side.
Under driven screws: These are a result of insufficient torque on the screw to properly seat the rubber washer to the metal roofing panel. The rubber washer is never compressed and no gasket is formed.
Screws driven at the incorrect angle: These do not enable the rubber washer to sit flat on the metal roofing. Part of the screw is sealed however part is not sealed.
Screws that have actually missed the metal strut or wood framing listed below: These have nothing to seal against. These can be difficult leaks to discover as many times the screw is their but without touching it you wouldn’t understand that it didn’t hit anything and didn’t seal.
Even if the screws were set up correctly with the right amount of torque it does not suggest that the rubber washer is safe. Hot summers followed by tough cold winters are unkind to the rubber washers. They deteriorate and lose their seal and it can be extremely tough to distinguish which screw is dripping and which is not.
Metal_Roof_Leak _. jpgAnother area extremely vulnerable to leaks on a metal roof is the area around stack flashings. Stack flashings are the” boots” or flashings around pipelines that come out of the metal roof. HVAC vents, air vents, and plumbing pipes all have to come and vent through the metal roof. The stack flashing is how the pipe is water proofed. A lot of stack flashings are rubber or rubberized material that sits flat on the metal roof and forms a seal however also “squeezes” around the pipeline to form another seal. The motion in the metal roofing from expansion and contraction is constantly testing these seals.
The sun also breaks down the rubber flashings which last just about half the time of the metal roof. The more caulking, sealant, or tar that is put behind and around the stack the more they seam to pond water and leak, it’s a catch 22.
Plan on changing used or rotten stack flashings in order to keep your building dry.
Metal roof sealants that are installed in conjunction with a metal roof hardly ever last as long as the metal roofing panels do and need to be changed with routine roof maintenance. Sealants under trims such as metal ridge caps and Z flashings, around roof transitions, counter flashings, reglets, and pitch pans will all need to be “topped off” from time to time as they use. Utilize a metal roof sealant particularly made for metal roofing. Other types silicone caulkings might not comply with the paint on the roofing panel and trims. Metal roofing goes through a daily growth – contraction cycle and if any sealants are to last they should be able to remain versatile and stretch with metal without breaking their seal.
HVAC systems on Metal Roofings are typically resting on curbs. Setting up metal roof panels is a fairly easy process but it’s the flashing that actually check a metal roofers ability. When making the flashing and keeping a curb dry can be simpler stated than done, hvac deal little room for error. The up hill side of curbs and the two upper corners of the curb flashing are challenging locations particularly on lager HVAC units. Water frequently gets trapped behind the system and “stands” behind the flashing which eventually begins and erodes sealants to leak. The more you caulk, seal, or tar the uphill side the more water it will hold. This Catch 22 is challenging to correct without removing metal roofing panels and starting over.
Seams and overlaps.
Since of a condition called capillary draw, seams where 2 pieces of metal roofing over lap each other often leak. When water can in fact take a trip up hill in between two securely joined pieces of metal, Blood vessel Draw is. Sealant or butyl tape between the two pieces of metal can break the capillary draw however if not used correctly can actually make leakages worse than if none had been used at all.
Check out our good friends at Exterior pro roofing https://www.exteriorproinc.com/blog/metal-roof-repair-5-common-causes-of-metal-roof-leaks