Good day everyone and I trust this finds you well. Insofar as our series on leaky roofs goes,today we are looking at a sheet metal roof installed on a low slope. A sheet metal roof installed properly should not any repair work.It is a roof system designed to last a long time. If it is of the hidden fastener,standing seam variety it should last 50 years. Now depending upon the climate and geographical location of the structure the metal roof is on,it may require more or less seasonal roof maintenance to keep it functioning optimally for its warranted life.
Insofar as today’s metal roof repair is concerned the actual field work isn’t the problem. The devil is in the details. When this roof project was done new bathroom fans were installed in all the units. These bathroom fans need to exhaust through the roof. It makes sense to do these concurrently as the vents can be flashed into the new metal roof system from day one. However,for some unknown reason,half of the vents installed were sheet metal vents matching the roof system and half of the vents were of the plastic type that are used on a sloped shingle roof. These first two photos depict the type of metal vent we want installed into the roof system. Half of the vents come up through the metal roof panels and tuck under the ridge cap. The other half of the vents are mounted on a curb.
Below are three images of the plastic damper vents one would use in say a fiberglass laminate shingle roof system.These plastic vents are not designed to be used on such a low slope and neither are they supposed to have a dozen screws driven into their flanges. Our metal roof repair today is going to include removing the old plastic vents which have cracked and split and will leak if not addressed ASAP. We will install some custom made sheet metal vents to replace them.
Metal Vent Installation
To begin the repair work and the installation of our new metal vents the first thing we do is remove all the fasteners holding the vents to the metal roof panels and the curbs.Once we have the fasteners removed we need to break the seal where caulking was used to prevent the weather from getting into the building. This is another no no where these plastic vents are concerned as some roof cements can actually eat them away. Put the old fasteners in your nail pouch and don’t litter the roof with them.They can be stepped on and damage the roof.
The fasteners along the ridge cap will need to be removed as well because the new metal roof vent will need to be slid up under the capping. With the vents loose,gently pull them up to expose the sealed joint where the roof vent joins the duct work coming from the fan.In this case,the vents are tapped to the ducting. Simply peel off the tape and discard with the old vents. Ensure the stem of the vent is the same diameter as the exhaust fan ducting. In this case we are using a 6 inch metal stem vent that is connected to a 5 inch duct and maximized from 5 inch to 6 inch.Connect the vent stem to the duct work and seal with an appropriate material. In this case I’m using Gorilla tape. Apply a continuous bead of sealant around the top of the curb,set the vent into the sealant and fasten at each corner onto the curb with neoprene washer head sheet metal screws. Clean up the work area. Rinse and repeat :)And there you have it. A little metal roof repair