Lance Grandone
HOA
2/15/2011
I live in a deed restricted community 5 miles from the Gulf of Mexico in Florida. We are currently restricted to tile and cement roofing material only. There is a movement within the community to change the deed restrictions to permit metal simulated shake, shingle and barrel tile roofs (The vertical panel style would be prohibited due to architectural style incompatibility). The community consists of single family homes primarily built during the early to late 1990’s with under-roof areas between 2100 and 4000 square feet. The roofing system used is known as “engineered trusses” which designed to support and distribute the weight of the roof. A small but vociferous minority that is anti-metal roof are making the following claims: 1. Metal roofs are much lighter, therefore less strong and more susceptible to wind damage. 2. Steel (or metal) roofing is not yet certified to Miami-Dade wind standards. 3. Metal roofs are more prone to leakage due to more holes (from screws and nails) required to affix metal roofs to the underlayment. 4. The metal roofing comes in strips. These strips must be bent or sheared at valleys, ridges and edges. This exposes a cut edge that must be touched up and sealed according to the manuals. If the roofs are to be walked on the steel roofing needs to be supported underneath. Many homes in the subdivision use pool solar heating panels and or voltaic electric panels. The installation of these would require special reinforcing. Again, more fasteners through the underlayment and higher cost. 5. Brochures suggest that homes located near salt water use panels made from more expensive aluminum. It is also necessary when installing metal panels to use nonmetallic flashing, material other than aluminum, copper, or lead as these would cause electrolytic corrosion. 6. Metal roofs corrode just like an automobile exposed to the weather without cover. The roofing also is coated to inhibit corrosion and must be sealed at all edges to protect from invasive water. They suggest that future maintenance may require repainting. The manuals hint that steel roofs without the cleansing effect of winter snow will need to be cleaned. 7. The installation manuals call for open "valleys" [about 8"] where roof slopes come together. Our cement tiles abut at the valleys showing no recessed openings. Metal roofing seems to be capped at all edges to keep the wind and weather from getting underneath. This is not necessary with tile at every instance. 8. There is no evidence that metal roofs are less expensive than concrete or tile roofs. Are any of the above statements correct? I would like to be able to use metal roofing but am unsure that our residents are receiving the correct information about metal roofing.
Info @windowsonwashington.net
An informed customer is our best customer.
2/16/2011
1. Lighter, yes. More susceptible to wind lift off, not when fastened properly. 2. Not true. There are several metal roof systems that are Miami Dade certified. 3. Not true. Most metal roofing systems (higher end) utilize a hidden fastener style system and are no more prone to leakage than concrete or clay roofs. 4. Each metal roofing profile will have specific walking instructions but they largely walkable and do not require any more special treatment in the valleys than most roofs do. Some systems use closed valleys where others use open. Both are okay and fine for your purposes. 5. Aluminum is less prone to oxidation in salt water environments than steel, however, most of the good metal systems use some sort of coated steel (Galvalume, Galvanized, etc.) on their panels and are very comfortable in salt water conditions. The cathodic reaction of dissimilar metals must be accounted for but every metal panel manufacturer that I know of accounts for this in their recommendations and accessory panels. 6. There are case studies of metal roofs in coastal applications that are 35+ years old without requiring re-coating. Take a look at Decra panels. They have some examples over on their website. 7. Not necessary in all applications but typically used as an aesthetic component. There are certain starter panels that you can cut and tuck your metal roof into without a cap but the cap usually looks better. 8. Depends on who is selling them. I have seen instances where they absolutely are less expensive. Good luck.
Nate Libbey
2/16/2011
Lance, Here are answers to your questions: 1. Metal roofs are much lighter, therefore less strong and more susceptible to wind damage. A) One of the great aspects of steel is its strength to weight ratio. Most metal roofing has the highest wind ratings available. 2. Steel (or metal) roofing is not yet certified to Miami-Dade wind standards. A) Many metal roofing products are Miami-Date approved including Products from Metro Roof Products, Classic Roofing Systems, Allmet, and Gerard, to name a few MRA manufacturers that produce simulated tile and shakes. 3. Metal roofs are more prone to leakage due to more holes (from screws and nails) required to affix metal roofs to the underlayment. A) The fasteners used and installation methods for metal roofing are designed for longivity. Also many of them use hidden fastened designs which hide all the fasteners. 4. The metal roofing comes in strips. These strips must be bent or sheared at valleys, ridges and edges. This exposes a cut edge that must be touched up and sealed according to the manuals. If the roofs are to be walked on the steel roofing needs to be supported underneath. Many homes in the subdivision use pool solar heating panels and or voltaic electric panels. The installation of these would require special reinforcing. Again, more fasteners through the underlayment and higher cost. A) As far as the cut edges, many times are designed to be or can be hemmed to protect the edge. Also the coatings when cut have a shear through action which somewhat protects the edge even if exposed. Many commercial buildings have had metal roofing which although designed differently, have had similarly exposed edges which have held up well for 30+ years. As far as supports, they vary by the type of metal roofing. Some metal roofing can be installed over batten systems, while others must go on solid decking. Metro, Gerard, and Allmet at least make systems that can go over either solid or batten systems. 5. Brochures suggest that homes located near salt water use panels made from more expensive aluminum. It is also necessary when installing metal panels to use nonmetallic flashing, material other than aluminum, copper, or lead as these would cause electrolytic corrosion. A) Most Steel manufacturers have a limit to how close they recommend it to be to salt water. Often this is around 1000 yards, but if varies by manufacturer. As far as the flashing, direct contact with lead and copper should be avoided, but contact with aluminum is completely acceptable. 6. Metal roofs corrode just like an automobile exposed to the weather without cover. The roofing also is coated to inhibit corrosion and must be sealed at all edges to protect from invasive water. They suggest that future maintenance may require repainting. The manuals hint that steel roofs without the cleansing effect of winter snow will need to be cleaned. A) The coatings on metal roofing, whether paint or stone coatings, are designed to protect against the elements. They usually will have a warranty limit on the coating of the roof from 40-50 years, although they should last somewhat more than that in most cases. Check with the particular manufacturer for their warranty and what it covers. Cleaning the roof periodically with fresh-water, especially in salt-water environments, is not a bad idea, although not usually required for the warranties to remain in effect. 7. The installation manuals call for open "valleys" [about 8"] where roof slopes come together. Our cement tiles abut at the valleys showing no recessed openings. Metal roofing seems to be capped at all edges to keep the wind and weather from getting underneath. This is not necessary with tile at every instance. A) Installation manuals vary a lot depending on the product. You may want to check with this particular manufacturer for more information. Some MRA member products have open valleys, others closed valleys, while others can be installed either way. 8. There is no evidence that metal roofs are less expensive than concrete or tile roofs. A) Pricing varies a lot by the product. In general I have found that the products I have used have been slightly less than concrete or tile, but also metal tile roofing is generally faster to install than actual tile. Also due to it being lightweight, metal roofing often doesn't require the extensive support that heavy tile requires.
Nate Libbey
2/16/2011
@windowsonwashington: Good answers! I had started typing up my answer and didn't see yours until after I sent it :)
Lance Grandone
HOA
2/16/2011
Many thanks. I now feel comfortable in committing to a metal roof.
Info @windowsonwashington.net
An informed customer is our best customer.
2/16/2011
@Nate Thanks. You too. Brilliant minds obviously think alike. Ha ha!
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