Roof slope is a very important aspect and it is considered the primary factor in roof design. The slope of a roof has an effect on the interior volume of a building, the drainage, the style, and the material used for covering and ultimately the cost. Below is a small summary of the advantages and disadvantages for both low slope and steep slope roofing systems.
LOW SLOPE & FLAT ROOF
Advantages: Require less material to build; less time to roll out and seal roofing materials than installing individual shingles; allows for easy maintenance since walking on a flat surface is easier; limits extra air and makes a structure easier to keep comfortable because a low slope roof limits this extra air and makes a structure easier to keep comfortable throughout the seasons.
Disadvantages: Changes how water flows off of the structure. On a roof with a lower pitch, standing water soaks between asphalt shingles and other overlapping materials. Shingles can’t be used on roofs with a slope below 8.5 degrees. Only rolled sheet roofing works on flat or very low sloped roofs.
STEEP SLOPE ROOF
Advantages: 50 percent longer lifespan than other roofing installation methods; faster water runoff, depending on pitch; lower chances of debris buildup, mold and mildew proliferation; can be covered with roofing materials that are fabricated and applied in small, overlapping units (shingles of wood, slate or artificial composition; tiles of fired clay or concrete; or even tightly wrapped bundles of reeds, leaves, or grasses.)
Disadvantages: Cannot cover a building of any horizontal dimension because it becomes too tall on a broad building.
For more information on Green Roofs, Low Slope and Steep Slope Roofs, contact the professionals at Jottan at 800-364-4234 or visit our website: www.jottan.com
A rooftop garden or a green roof can be as simple as containers and raised beds to roofs covered with soil and plants. While the terms are often used interchangeably there are differences which we explore below.
Green roofs can be as simple as a 2 inch covering of hardy groundcover or as complex as a fully accessible park complete with trees (not recommended for the traditional/conventional residential dwelling). While both green roofs and rooftop gardens provide environmental benefits, give sanctuary to animals and insects and do their part to improve air quality, a green roof is designed for maximum environmental benefits. By absorbing heat and acting as insulation, a green roof reduces energy needed to provide cooling and heating. While rooftop gardens provide shade and partial insulation, they will never provide the same benefits because rooftop gardens do not cover the entire roof of a building.
Other benefits of green roofs are: decrease in the production of associated pollution and greenhouse gas emissions by lowering air conditioning demand; and improving human health and comfort by reducing heat transfer through the building roof thus improving indoor comfort and lowering heat stress brought on by heat waves.
Green roofs focus on efficiency and lightness, while rooftop gardens are more aesthetic and created for their beauty or utilitarian purposes. Rooftop gardens can be created with the use of containers and raised beds and for far less than a green roof.
Though initially more expensive to install than conventional roofing, the financial benefits of a green roof are realized over the lifetime of the roof. The cover protection that a green roof provides means a longer life span compared to conventional roofing materials. Its natural insulation properties help buildings retain heat in the winter and protect the black tar from heating up in the summer thus reducing the energy needs for the building.
Regardless of whether you are installing a rooftop garden or a green roof there are certain issues to take into consideration.
- Care must be taken to ensure that the building is structurally sound and can hold the additional weight.
- Safety, for those on the roof and for those passing by on the ground. Ensure that equipment, containers and furniture are safely secured and that nothing is protruding upward from the floor of the roof.
Sources: www.epa.gov and voices.yahoo.com