The most common roof decks used on flat roofs are steel roof decks. They are made out of cold-rolled sheets. Cold rolled refers to when steel is shaped into the decking or roof panels at room temperature. There are ribs in each panel that make them strong and rigid.

Ribs are referring to the grooves in steel panels that make them strong.

 The panels come in many thicknesses, sizes, and spacing of ribs.

Many roof decks are used on flat roofs, but steel roof decks are the most popular choice in the industry today.

Other Roof Decks Installed on Flat Low-Slope Roof Systems

Cement Wood Fiber Roof Decks made from wood fibers. These are bonded together with cement and other binders. Then they are pressed together and molded into panels.
Gypsum Concrete Roof Decks made of gypsum material mixed with fillers.
Structural Concrete Roof Decks either poured on site or made into planks and then set in place.

Many types of wood roof decks exist as well, such as wood plank, plywood, and oriented strand board.

Insulating Concretes – light weight insulating concretes can be used as fills or toppings. Insulating concretes can be poured over another surface like corrugated steel or form boards.

Low-Slope Flat Roofs

The slope is the incline of a roof. A low-slope roof or commonly refered to as a flat roof, is a roof with a slope of less than 3 inches per foot. Commercial and industrial public buildings usually have low-slope roof systems. Low-slope roofs are commonly found on commercial and industrial warehouses and factories, but are also found on many apartment buildings and townhouses as well.

Why Low-Slope Roofs are Not Completly Flat

Low-slope roofs are constantly referred to as flat roofs, though they are not exactly flat. They may appear to be flat, but most roofs on commercial buildings have at least a small slope of 0.25 inch per foot. The reason why these roofs have a slope and are not completely flat, is to allow water run off. It’s important that the roof has a good drainage system, so that water will run off, and not cause ponding. Ponding is when large puddles of water stay on a roof for an extended period of time. The slope of a roof is designed to assist the drainage system to avoid problems associated with ponding water.

Flat Cool Roofs

Cool Roofs are roofs that are designed to maintain a lower roof tempertature than traditional roofs. The sun is the primary factor that causes a roof to become hot. Cool Roofs reflect the suns UV rays, and emit heat more efficiently than hot dark roofs, which helps keeps them cool.

Common Myth About Cool Roofs:

Not all cool roofs are white!

Types of Cool Flat Roofs

-Reflective Roof Coatings
-Single-Ply Membranes: TPO, PVC, and EPDM
-Built Up Roofs
-Modified Bitumen
-Spray Polyurethane Foam

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.