caulking, jacks, and curbing

Guest User
10/9/2002
I recently had a galvalume roof installed on my home. The finishing was so sloppy and unprofessional in appearance that I called a housing inspector. He documented applications that he said would be unacceptable as they would lead to leakage in the future, and his bottom line was that he would not accept the roof if it were on his home. First, there is excessive use of caulking in areas that he recommended flashing and counterflashing, as the caulking is going to deteriorate in the environment. The roofing company has offered to remove the excess caulking to make the appearance more attractive. Should this be an acceptable offer? Lead roof jacks were used, which is a dissimilar material. I have an article by Ken Buchinger, who specifically says that dissimilar metals should not be used as this will cause corrosion, and rubber jacks would be the non-corrosive accessory of choice. The roofing company says that they only will warranty lead jacks, and if any other type of jack is used, they will not warranty their work. Obviously, this was a big project, and an expensive one, that I expect a warranty on. A 10 year workmanship warranty is in the contract. What are the scientific facts on dissimilar materials on metal roofs? What are the industry standards on proper materials for roof accessories? A power vent was installed, which is from 18-24 (I will have to go to Home Depot to view one to get the exact measurements) inches in diameter, and a larger flat square base. The power vent installation shows lots of caulking also. Does this seem like an acceptable installation, or should curbing have been used? Thanks in advance for your input. Lily Engles San Antonio, TX
Allan Reid
Dura-Loc Roofing Systems, Inc.
10/9/2002
These are stories we do not like to here. Lead- "As with Galvanized or Galvalume steel, contact with lead can result in an accelerated corrosion of the coating in the area of contact. The rate of corrossion increases with the severity of the environment." This will void the material warranty in the affected areas. I can fax you a technical bulletin on the subject if you email me a fax number or you can go to the NAMZAC association (Galvalume) and request info. Caulking- If caulking made a good roof we would all be out of business. It a required ellement in joining dissimilar materials to all for structural movement. There some approved details by manufacturers that allow for the use of Butyl tape to make junctions and surface mount certain flashings. We do suggest that you contact the manufacturer of the material and get their opinion. If a generic metal profile was used, you can contact SMACNA the sheet metal association who publishes nationally recognised flashing details. Power Vent- Not knowing the profile of roofing you had installed, however it is normal proceedure to install them centered on a sheet or if larger than two sheets to center them on a joint. Typically they are installed near the ridge which means it does not have to deflect any large amounts of water. If it comes with its own flange, the sheet roofing is installed to the top of the vent hole. then the vent is installed over the lower sheet embedded in two rows of butyl caulking tape. An upper sheet is then laid over, cut around the vent and lapped down past the centre of the vent. Make sure the upper sheet is cut about 2" larger than the vent stack size to allow the water to run around. Now obviously the vent would come with a flat flashing and the metal roof has a profile which makes it difficult in laying the flashing over the lower sheet. Experience comes in here on forming the transition and certain manufacturers make transition pieces. It appears as if your contractor and or his installers ran into some details they may not have been familiar with. Your hold backs are for such instances and I would gather the information and request that he deal then correct it. Good Luck.
Guest User
10/9/2002
Thanks for your expertise. The roof is an ordeal at this point in time. I will be glad when this is resolved. I would appreciate the technical bulliten about lead/galvalume/corrosion. My work fax number is 210 531 7331. Please mark it Attention: Lily Engles. I will follow through with your recommendations about the details on the flashing. From what you are describing about the power vent, it is installed as you described, except a bit off center on a seam. It does have thick noticable caulking all around its sides and the bottom edge. I doubt that it is butyl tape caulking due to it's non-uniform appearance. Is this another area where I should be concerned about dissimilar materials and corrosion? I doubt that the flashing of the power vent is galvalume, it looked like shiny steel to me. If need be I can go to Home Depot and find out what the vent flashing is made of. Lily Engles
Guest User
5/6/2009
Ms. Lily, I am a metal roof installer in Flora, Ms. near Jackson. I am presently involved in a situation in which the contractor I am working for is telling me I should use a lead roof jack which I think is contra-indicated due to the fact of using to [dissimilar] materials, viz., lead and steel. What I am requesting from you is did you get your questions answered about the electrolysis factor of two dissimilar metals when doing metal roofing. I don't want to sound like a novice; I am not, but I'm dealing with people (contractor) who wants me to do something I know will void the warranty of the material(s) and my labor if I do what they want. I just happened upon your situation on the net while researching information about electrolysis. My fax & phone number is- Burgess Enterprises, Inc. @: 601-879-3676 Cellular: 601-937-2413 Thank you so much, Michael Burgess Burgess Enterprises, Inc.
Find a Contractor

Get Started Today

Take the first step to increasing the value of your home with a great looking, durable, fire resistant and energy efficient metal roof. Browse our list of qualified MRA Member Roofing Contractors in your area for a free consultation and estimate.