Metal roofs don’t get much more complicated than this in the middle of Miami Dade with four attached flat roofs. Roofer Mike breaks it down with an emphasis on the more important aspects of metal roofing.
These metal roofs in Miami Springs had it all. They included four attached flat roofs, six valleys, chimney, cricket, six vertical walls and a scupper replacement with back-up. There were concrete flat roof additions built across the front of the house over the porch and carports. Before we could do anything we had to build a bridge just to access the job.
In a recent video I stated that the most important aspect unique to metal roofs was the importance of the manufacturer and installer. Who is producing the trim pieces and panels? Who is installing them? Years ago, after visiting most of the local metal shops, we settled on East Coast Metals. Their facility was bigger, more modern and 100% dedicated to metal roofing. Our installers are very experienced beginning with the foreman, who has 25 years of Miami roofing under his belt.
The most important part of a metal roof installation overall is the treatment of the substrate or wood decking. After the existing roof is torn off all rotten wood must naturally be replaced and re-nailed to Code. We don’t stop there. A metal roof is often chosen for its strength and wind resistance and is only as strong as the substrate supporting it. More than any other system metal roofs reflect the decking. We do our best to eliminate any irregularities which can take away from the aesthetic. Once the deck is stable it is dried in with 30lb felt and a layer of Versashield, a fire-proofing product.
Perhaps the most important aspect of this particular job was the integration of the four flat roofs and metal roofs. First we replaced all the flat roofs with a 1 ½” insulated GAF 3-ply Ruberoid low slope system. Care must be taken with the flashings so the metal crew can easily tie in later. Ruberoid systems are simply better and, more importantly, more durable than the mineral surfaced cap sheet system sold by others. It’s important to install a robust flat roof when tied into a metal roof system, potentially a lifetime roof. We also stress flat roof maintenance to the owner for the future, the goal being to have the flat roofs last just as long. This system gives them a head-start with an aluminum roof coating applied at completion to achieve a Class A fire rating.
Each roof presented challenges, particularly one surrounded by sloped roofs and vertical walls with a lone scupper for drainage. We replaced the existing 3” x 3”scupper with a 4” x 5” and cut the wall for a 4”x 5” back-up, per Code. Clogging will be much less of a problem.
Once the flat roofs were complete the job became a matter of having the metal roof components delivered and installed which, by contrast to all the previous work, was fairly straightforward.
One additional note – over the years I’ve noticed mill-grade roofs stay cleaner than those that are factory-painted. Galvalume sheets consist of a galvanized roll that is run through a molten bath of 55% aluminum and 45% zinc. It is the zinc that disrupts the PH of the panel surface and kills the fungus, algae, bacteria and mold spores. Roofs with painted panels seem to be staining very quickly. Whatever biocides are in the paint do not hold up to South Florida’s flora and fauna.
By Michael Slattery