ATLANTA — A major weather system heading toward north Georgia is forecast to bring several inches of snow and ice to metro Atlanta.
A winter storm watch was issued for metro Atlanta and north Georgia by the National Weather Service for accumulating snow, sleet and rain. The watch begins Sunday evening and continues through Monday evening.
“This storm system will bring us a significant amount of snow and ice”. Across metro Atlanta, 2 to 3 inches of snow and sleet are expected to accumulate. The northern suburbs could see 4 to 5 inches of accumulation and the north Georgia mountains could see 6 inches or more. Read the full article => http://www.wsbtv.com/weather/26398414/detail.html

Snow on a Roof

Snow/ice on a roof can present major problems, because snow/ice is basically frozen water. So it is basically equivalent to having water ponding on your roof, which you are aware can cause structural damage.

Interesting fact: Water weighs 62.4 pounds per square feet.

If enough snow/ice is on your roof, the weight alone could cause damage. This is called snow loading. Snow loading is the downward force exerted on structures by the weight of accumulated snow.

Here is an article on commercial roof grease cleaning in Atlanta that shares some information on the effects of grease on a roof.

Here is an interesting article: Ice and Snow Accumulations on Roofs  The article comes from the University of Arkansas division of Agriculture.

Flat Roofer

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Flat Roofer

Flat Roofer is constantly updated with new articles of information on the roofing industry. This site covers much more than flat roofing, it covers a wide variety of issues associated with the roofing industry. We offer valuable information for residential, institutional, industrial, and commercial roofers.

 Please take the time to search the site, roofers and consumers, are both welcome here. If we can be of any help to you, in any way, please feel free to contact us.

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Picking a Cool Roof

Most roofing industry experts agree that a cool roof is one that exhibits a combination of high reflectivity and high emissivity. But the questions have always been how high is high and what combination of the two yields the most benefit?

One way to make a decision is to use the Solar Roof Index (SRI) to evaluate a cool roof. The U.S. Green Building Council’s LEED 2.2 uses SRI as a way to evaluate a cool roof. LEED version 2.2 is the first national specification to use a relatively new measure of reporting a cool roof’s properties. LEED 2.2 sustainable sites credit 7.2 states that to receive one point, building owners should use a roof with a Solar Reflective Index (SRI) of 78 over at least 75 percent of the roof’s surface for slopes less than 2:12.

SRI is a unit developed by scientists at Lawrence Berkeley National Laboratory. SRI incorporates reflectivity and emissivity properties into one, easy-to-read, standardized measure so that roof buyers won’t have to scratch heads and try to figure out if a high reflectivity and low emissivity is better or worse than a medium reflectivity and high emissivity.

SRI is calculated with a complex formula spelled out in ASTM E 1980 and is a scale of 1 to 100 that is a measure of a roof’s combined thermal properties. It is defined so that a standard black (reflectance 0.05, emittance 0.90) is 0 and a standard white (reflectance 0.80, emittance 0.90) is 100. But some hot roofs can have negative values, and some white thermoplastics and white roof coatings have scored as high as 104 to 110.

SRI as a method for reporting cool roof data will probably take a little while to catch on. Most manufacturers still report separate emissivity and reflectivity data in their literature, but the Cool Roof Rating Council, an organization that verifies and labels cool roofing products has begun using the measure, while retaining reflectivity and emissivity measurements.

Different roofing technologies have different SRI values. Asphalt coatings for example have aluminum pigments added to asphalt cutbacks and emulsions to give coatings solar reflectance index (SRI) values of 21-30 on a scale of 0-100.

Acrylic elastomerics on the other hand, a new-generation coatings, have a highly reflective surface, often with an SRI greater than 100. Most highly reflective acrylic elastomerics are white, and workers can install them over existing bituminous or non-bituminous roofing. Acrylic elastomers typically are specified at 12 mils for five-year warranties and at 20 mils for for 10-year warranties. Some manufacturers specify up to 40 mil applications.

Sources: Building Envelope Ripe For Energy Gains by Lindsay Audin
Making Roof Coatings Work by Wade L. Vorley
FacilitiesNet – http://www.prlog.org/11830326-newly-launched-roofing-site-for-facility-professionals.html

Roof Garden & Green Roofs

Do these terms mean the same thing? Many people ask or assume they are the same. And depending on the resources you read, they might indeed tell you that a Green Roof is a Garden Roof.

A green roof basically reduces energy by using green technology. Some refer to white being the new green, because most green roofs have some form of white coating or layer on the surface to reduce heat. Most roof systems have very low emissivity and very low albedo which results in high surface temperatures and elevated conductive heat transfer. Especially in roof systems with black surfaces, that absorbs heat. A green roof will reflect heat, which in return will decrease the heating and cooling cost. Many also refer to green roofs as cool roofs, because they keep the roof “cool”.

A roof garden is different from a green roof, although the two terms are often incorrectly used. A roof garden or garden roof is just that a living growing garden on a roof. While most roofs would be in bad shape if plants were growing on top of them, a roof garden is designed to do so.