Miami Green Homes


South Florida Roofs – a green roof choice and opportunity

With Hurricane season in full swing and a wet shower passing through with “Nicole”, we are reminded of just how important a good roof is in South Florida. Besides a good seal and protection for your property the roof does a lot more than to top of your shelter.

Ensuring that the roof is installed correctly and will protect form wind and rain remains the first priority. This is regulated by both the Florida Building Code and the Miami Dade Product Approval process and any state licensed contractor in combination with a proper building permit will comply.

There is more to the roof than just protection. In South Florida the roof is responsible for almost 80% of the heat that is introduced into the building on a typical residential and low rise commercial structure. This means that conditioned space must address this heat load. Sure, natural shading will help to reduce the heat gain impact but is not always feasible to be installed in an ideal location. Please see some of the landscaping posts for additional information.

To reduce the heat gain through the roof, there are numerous options available. The first layer of defense is the roof finish. Options for the roof finish that are available under building code and product approval generally include asphalt shingle, barrel tile, concrete shingle, flat roof membrane and metal. Some cities, such as Coral Gables, further restrict these options to maintain a design intend and general appearance for the city. When applying for a permit, the available options will be outlined.

a green roof

Within the noted finishes my clear favorite is metal. Considerations of flying tiles (frequently occurring with barrel and concrete tile roofs), dark colors that will attract a lot of heat (generally asphalt shingles) or flat roof design limitations (how many homes have flat roofs…) make metal roofs the winner. It provides a safe installation that will best resist any hurricane strength winds, provides a light color that not just reduces heat gain but also reflects, and finally also provides the best surface for water collection (a nice bonus).

It is not the least expensive option, but has one of the longest life spans, making the overall investment well worth it.

Design consideration must always be taken into account, but the metal roof has a long history in South Florida and the Florida Keys.

The next barrier is insulation. Often this can be found dropped on the ceiling, which is the wrong location for roof insulation. The building code again provides for minimum levels to ensure a degree of energy efficiency, but simple changes can substantially improve the efficiency of insulation.

To start, it should be installed on the underside of the roof, ensuring that the attic cavity becomes part of the conditioned space. What good is insulation on the ceiling, when water and HVAC systems generally run through this area? Why run them through a sauna like heated space, easily reaching 140+ degrees, when this space can be conditioned, and can be under 100 degrees. Energy is saved by not cooling the wasted 2-4 degrees in the duct and the water pipes.

As there are no HVAC outlets in the attic, it is still a good idea to provide insulation on top of the ceiling, again a small cost of initial installation with a quick payback.

Runs of water and HVAC ducts should be taken into account to further optimize energy savings.

With the above tactics, the roof will be a sustainable shield that will help your home to be more green and keep you some green in your wallet, too. When repairing or replacing your roof, think about this opportunity!

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