As previewed in our Home Inspections newsletter, this discussion revolves around roof shapes and roof coverings: their affect on a homes integrity under heavy winds or hurricane conditions as well as their affect on insurance rates and availability.
The Hip Roof as previously mentioned is currently the most popular as far as new construction because of its superiority to heavy wind load. Hip roofs, sloped to roofs edge on all sides, are the predominant roof shape found here in SW Florida, where much of the construction had occurred in the last 25-30 years. Insurance companies in the State of Florida generally offer a substantially cheaper rate for the hip shape as opposed to others, notably gable roof systems. Wind Mitigation is an insurance program here in Florida that rates a home against the stronger winds, the hip shaped roof offers a discount through this report as well. There are many homes though that have other featured shapes tied in to a roofs total perimeter, such as a flat patio roof or reverse gables which can cost a home its hip rating with an insurance company, dependent on total square footages of each. The wind mitigation report calls for no non-hip features greater then 10% of the roof total perimeter. Many times a flat roof over the rear patio or a few reverse gables will measure greater then 10% of the perimeters square footage, rendering what appears to be a hip roof as "Other roof shape" in the report and sending the homes insurance premiums back up to higher ammounts! This is an important piece of information for ANY professional in the real estate industry as well as anyone in the market for a home.
Know these simple facts when looking at houses, whether be for yourself or a client. Education is power! Remember also, if you do have a home that is not a hip or it is a Gable Roof, all is not lost. You may pay a few more dollars in insurance but most homes today are built with formidable truss systems no matter what shape it is finished. It is more about the type of covering that the roof has and its integrity, as well as flashing and other important components in a roofing system. Preventing water intrusion and proper ventilation of the roof will go a long way in keeping your family comfortable and safe as well as getting the most longevity and cost efficiency our of your roofs covering.
Here in SW Florida, there are basically 3-4 roof coverings used 99% of the time. Asphalt Shingle, three tab or architectural, may be the most widely used roof covering here as well as throughout the United States. Based mainly on its economic value, Three tab asphalt shingles have average lifespans of 15-18 years, while Architectural asphalt shingles last a bit longer at 20-25 years here in SW Florida. Our scorching sunlight here in paradise is a major factor in shortening the lifespans of most asphalt shingles. Other factors affecting an asphalt shingles lifespan include:
- The roofs pitch, higher pitched roofs tend to last longer.
- The color of the shingle, a dark roof absorbs more heat which shortens a lifespan.
- The orientation of a roofs surface, the south slope of a building will take on more sunlight, in effect shortening its life.
- Multiple layer roof, a roof covering installed over an existing covering will not last as long its average life expectancy. it is always recommended to remove the old covering before applying the new, increasing the ventilation value as well.
- Tree branches overgrown and hanging onto a roofs covering will damage the covering over time, basically wearing it off with the acidity of the trees branches and leaves. We have been on multiple roofs where the asphalt shingles granules have worn right off from this condition, thus creating a haven for the beginnings of water intrusion to the roofs deck, and eventually, the home.
Poor installation and "economy" roofing materials will shorten lifespans as well. With an Asphalt Shingle roof in SW Florida you will more than likely replaced it every 15-20 years, due diligence in choosing the proper material and craftsman for install and replacement goes a long way in getting the job done the right way, and getting the most out of your dollar and your home.
The age of asphalt shingle, whether it be three tab or architectural, will always be a concern of the insurance companies here in Florida. Basically any asphalt roof coverings 15 years or older will need to be given a minimum of "3 years of life" by a licensed home inspector in order for the homeowner to get insurance. Not an easy task for the inspector, especially with some insurance companies now asking for five years! Just for the record, we are not required to estimate any lifespans throughout a complete inspection! Just not an easy task.
Another common roof covering seen here in the sunny south is Concrete or Clay Tiles, found on many newer homes, in gated communities with mass builds and featured generally as an upgrade because of its higher cost, cosmetic brilliance and longer lifespans. Concrete and Clay Tiles have an average lifespan of 35 -50 years depending on style and finish. Tile roofs are installed differently, generally interlocked or overlapped with lugs on their underside for anchoring to a batten system on roof deck, draining rainwater down slope and off edge of roof or into a recommended gutter and leder system. As with asphalt shingle, there is also an underlayment between tile and roof deck, generally a felt paper or SWR. Secondary Water Resistant underlayment is self adhering and thicker then felt, coming in a foam finish. This type of SWR Underlayment is also a wind mitigation discount if the inspector or homeowner can document its existence, saving the homeowner more money on their homeowners insurance. Concrete and Clay tiles are a more fragile roofing system than asphalt shingle, delicate to walk on and easy to crack or damage if stepped on improperly. Most home inspectors will choose to not walk a tile roof during their home inspection with the inherent risk of damaging tiles while doing so.
Metal Roofs or Coverings are also seen on select structures and buildings, this covering easily being the most energy efficient and longest lasting. As much as 70% of the sun may be reflected away from the home as opposed to a larger percentage normally being absorbed through such roof coverings as asphalt shingle. Roof coverings made from such metals as galvanized steel, aluminum and copper are known to last 35-50 years average lifespan or longer, depending on material, install, climate and conditions.
Almost every roofing system has a roof deck below the roofs covering. The Roofs Decking or Sheathing lies below the covering, usually a plywood or OSB wood system, 4 foot by 8 foot sheets attached with fasteners directly to the truss system or "skeleton" of the roof, visible in the attic during an inspection or viewing. The fasteners are the staples or nails holding the plywood or OSB into the wooden trusses, usually 6D or 8D in size. Identifying the size of these fasteners can be important for the homeowner as the larger nail (8D) and its spacing will qualify for another insurance discount through the Wind Mitigation report. All home inspectors should have a Zircon metal detector to take measured photos of spacing along a truss. Shiners or showable misses with fasteners are not always there. The right tools go a long way for all situations!
Ventilation is an important concept as well when considering a roof and its components. Asphalt shingle roofs will most often have ridge vent at the peak and soffit ventilation around the roofs edges. Without a ridge vent look for cut in roof vents or gable vents on each side wall. Tile and metal roofs will normally have roof vents cut in to roof slope and soffit vents at edges. Do be sure though that a ventilation system exists, a must for the wood and other products that exist within a roofing system.
Maybe the last thing I will touch on this time around as far as roofs are concerned is the existence or nonexistence of a Gutter and Leder System for Drainage and divergence of rain water from the home and its foundation. Many beautiful homes are built here in SW Florida without complete gutter systems and many times with no gutters at all! Why? Why risk what could become a major problem for your foundation? Complete install of a full gutter and leder system can run between 700.00 and 1600.00 dollars. Installed with materials. Not to mention the convenience of entering the doors and the garage of a home without a solid sheet of water coming off the roof in one of the many, almost daily storms we have here in Fla... not to mention protecting exterior components from the shower that comes with this runoff, a constant flow of heavy water on your AC unit, a pools filtering system, well system components or any other mechanical component along the outside of your home. Gardens? Concrete walkways and entries? They too will get washed out and vulnerable to damage without a proper gutter system in place...
I hope this ten minutes of reading the basics about a roof, its shape, its covering and its value to the insurance industry and the structure in general helped you to understand a bit more about this very important piece to the puzzle that you call home.