Typically, roof slope isn't the first thing to come to mind when thinking of a building's design - unless aesthetics are your first priority. However, the slope of a roof is very important when it comes to things like protection from wind and water, keeping your home or business comfortable year round and reducing a building's lifetime costs in terms of roofing repairs and replacements.
The slope, or pitch, of a roof is indicated by two numbers, separated by a colon - like 3:12. This figure indicates that the roof pitch elevates three vertical inches for every 12 feet of horizontal roofing material. Steep roof slopes have a pitch of 3:12 or greater.
Steep Slope Metal Roofs Are Ideal for Moderate to Severe Climates
Steep slope metal roofs are appreciated by designers, builders and owners who desire an attractive roof line and who value their sustainable and energy efficient properties. It's important to point out that a metal roof does not have to be installed on a metal building. They are just as easily installed on traditional wood-framed buildings and can often be installed right over a building's existing asphalt or shingle roof, which reduces installation costs and can improve a building's insulation value.
Outside from their aesthetic appeal, a steep roof slope makes the most sense in regions where there is high rain or snow fall due to the roof's ability to shed water, snow and debris.
Structural and Architectural Roofs
In most cases, steep slope roofing systems fall into one of two categories:
- Structural Roofs. Structural roofs are usually installed over open framing but are also applicable over a solid deck. They are available in a variety of styles, including vertical standing seam systems. These systems are fastened to underlying purlins with hidden fastening flanges or clips. Other options include tile facsimile metal roofs or corrugated roofs, both of which are installed using visible fasteners attached directly through the roofing material. Each of these products forms a watertight fit via overlapping and/or interlocking panels,
- Architectural Roofs. Unlike a structural roof that can be installed over open framing, architectural roofs always require some type of solid substrate beneath them. In most cases, this substrate is built using plywood, concrete or metal roof decks, or oriented strand board. There are a range of styles available for architectural roofs, including corrugated metal, standing seam panels and most horizontal metal panels.
If water or snow shedding is important to you, architectural roofs are probably your best bet as they do the best job. They are considered hydrokinetic, meaning they shed water - and water, ice, snow, debris - quickly.
5 Benefits of a Steep Slope Metal Roof
- Lightweight beauty. Steep slope metal roofs look great but are also lightweight, reducing the total load placed on the structural components and building foundation. On average, a steep slope metal roof weights between 40 and 100 pounds per square foot. While this reduces wear and tear on the entire structure, it is especially beneficial for buildings that are constructed in regions with higher seismic activity. Metal roofing panels are available in a wide range of colors and styles, so your roof can blend with virtually any color palette.
- Good for extreme climates. Even though they're lightweight, a high-quality metal roof system is engineered to meet the requirements of ASTM E1592, UL 580, UL 1897 and other severe wind and uplift tests. It can also accommodate heavy snow loads and will prevent your roof from the threat of standing water, which can lead to rust and corrosion over time. If you live in a climate where the average temperature during any winter month is 30° F or less, talk to your local building department - or the roofing manufacturer - about installing an ice-dam protection membrane. It may be a code requirement in your area and will certainly increase your roof's performance.
- Sustainability. Metal roofs are inherently sustainable because they are manufactured using an average of 25% pre- and post-consumer recycled products. At the end of the roof or building's lifespan, 100% of the metal can be recycled. This is a tremendous difference when compared with more traditional shingle or tile roofs, which are typically demolished and dumped into landfills. Metal roofs also receive credits by LEED and other globally recognized green building certification programs.
- Durability and longevity. Most metal roofing systems enjoy warranties of between 20 and 40 years. Even so, studies have shown that a well-maintained meal roof, which requires only minimal maintenance each year, will typically last for as long as 50 or 60 years or more. This means you will be spending significantly less to maintain, repair and/or replace your building's roofing system.
- Energy-efficiency. Perhaps one of the most exciting benefits of metal roofs is their ability to be covered with a reflective coating. These cool metal roofs both reflect UV light as well as emit stored heat back into the environment, resulting in a more comfortable interior and significant savings on cooling costs. Studies done on cool metal roofs indicate that building owners benefit from an average lifetime energy savings of up to 40%.
Steep slope metal roofs are more common for homes and buildings with a traditional designs, although they may not always be practical, depending on your building's location. Your architect and/or design and build teams can help you determine the roof slope that makes the most sense for your project.