CONSTRUCTION AND TYPES OF SLOPED/PITCHED ROOFS
MATERIALS AND BENEFITS
The construction of a sloped roof varies tremendously. There are many different architectural types with numerous Roof System options. Sloped roofs are very practical. For example, during the winter and rainy seasons, precipitation does not accumulate on a sloped roof and rainwater easily flows through the drainage system. Steep slopes allow snow and water to easily run off, which makes them excellent for high rain and snow regions. They can also be built purely for design purposes to add architectural interest. The sloped roof is the most popular residential design. The structure can be simple, complex, or combined.
CONSTRUCTION
A sloped roof does not collect water. A roof that has a slope of less than 3 inches per foot is considered flat. Slope is determined by the vertical rise in inches for every horizontal twelve inch length called the “run”.
A 7/12 roof means that for every 12 inches horizontally (the run), the roof rises 7 inches. Some common roof slopes (rise and run) and the terms which classify them, include:
Flat Roof: 2/12
Low Slope: 2/12-4/12
Conventional Slope Roof: 4/12-9/12
Steep Slope: 9/12 and higher
ARCHITECTURAL TYPES OF SLOPED/PITCHED ROOFS
- Lean-To
- Ridge
- Four Sided Sloped
- Half Hipped
- Hipped
- Gable
- Multi-Pitched Gable
- Mansard
- Pyramid
- Domed
- Broach
- Conical
- Vaulted
LEAN-TO
Lean-to’s have a truss system resting on walls of various heights. A ramp is formed because one of the walls is slightly higher than the other one.
It does not accumulate water, which slowly drains in the direction of the slope, so the draining system provides reliable dryness to the construction.
RIDGE
Ridge Roofs are popular for single family homes. Sometimes called a gable roof, it’s two-slopes rest on walls of the same height forming a triangle. Installation is more difficult than a lean-to, but material choices are increased. Ridge roofs easily cope with snow, rain, or wind, and look nicer than lean-to construction.
FOUR SIDED SLOPED
Four sided sloped roofs can be used for construction of any buildings that are at a sufficient distance from other facilities.
HALF-HIPPED
One of the varieties of hipped roofs, the half-hipped, has a truncated triangular ramp, usually located higher than the trapezoidal ramps. Its only drawback is the large amount of material needed to cover the parts of the roof that are adjacent to its edges.
HIPPED
A pyramid shape, built over a rectangular structure with a ridge across the top part of the roof and slopes on all four sides.
GABLE
A gable roof has 2 sloped sides of the same angle that meet at the top. It appears as a symetrical triangle. They are most common in the United States, especially in areas with heavy snowfall.
MULTI-PITCHED GABLE
This usually has a very complex structure due to a large number of external ribs and valleys. When installing the roof it is necessary to refer to those who have experience of its installation. It is used for homes of a polygonal shape with many different extensions and side mansards.
MANSARD
Mansard also refers to gable roofs that have broken line skates. The increase in the area and volume of the attic is called a mansard. Pentagonal shaped, gable mansard roofs are attention grabbing. A linear drainage system manages ponding of water on large, small, and flat areas.Attics are possible and creating an attic under the roof is the cheapest way to obtain additional space.
PYRAMID HIP ROOF
There are several types of hipped or hip roofs. As seen above, a normal hipped roof is built over a rectangular structure with a ridge across the top part of the roof. If there is no ridge, such that all four sloping roof surfaces meet at a single point, the roof is a pyramid hip. Three other conditions for a typical pyramid hip are: Four triangular surfaces, eaves of the same length, and a square base. A definite design advantage of the symmetrical pyramid hip roof is that it is striking from all angles.
It has an aerodynamic shape, so they are not easily damaged by high winds, are very durable, have overhanging eaves that provide shade for the building, and have a very distinctive look. On the other hand, they don’t allow for substantial attic space and don’t always encourage as much water run-off as a gable. Finally, the pyramid hip roof requires more materials to cover the larger surface area and the extra shingles and labor increase costs.
BROACH
A broach roof has four ramps of identical triangles which meet at a tipping point. The installation is difficult due to a very difficult truss system.
A broach spire is a type of pyramid conical structure, usually on the top of a tower or turret. A broach spire starts on a square base and is carried up to a tapering octagonal.
DOMED
Dome-shapes usually only cover part of the building. A frame of curved, soft materials, such as tar paper and shingles, and flexible galvanized steel or plastic tile are used.
Dome roofs are also formed out of curved frame elements, and planks.
CONICAL
Conical roofs are mostly used for buildings with circular contours and on frame houses.
VAULTED
The arched, streamlined design allows for airflow and does not accumulate snow or water. Different materials can be used to manufacture arched roofs. The main structural component of vaulted roofing is a light aluminum frame. The arched roof is ideal for covering large sports facilities, warehouses, commercial property and concert venues. Quick installation, light weight, reliability, and aesthetic completeness, are the advantages of vaulted roof systems.
SLOPED ROOF MATERIALS AND BENEFITS
COMPOSITION SHINGLES
Composition Shingles are made of carrier sheets that are coated with asphalt and granulated and are made in a wide array of colors. The last for 30 to 50 years. Many manufacturers meet Energy Star Requirements and certain product lines are eligible for tax credits.
ge Roofing offers Cool Roof Shingles that are Cool Roof Rating Council compliant and are eligible for the Los Angeles Department of Water and Power Rebate. For additional information, please click COOL ROOF to link to our website’s Commercial Flat Roof menu and scroll to the bottom of the page.
TILE
Tile offers true aesthetic value in many colors and styles. lat tiles are available that imitate the appearance of expensive slate roofing. High quality ceramic tile can withstand just about any climate condition. Tile is thermally efficient, a good insulator, and it can last for centuries when baked at a sufficiently high temperature.
Cast concrete, in any form, gets stronger as it gets older and is usually offered with a lifetime warranty. In addition, it is not prone to damage from insects, rot, or sun, is heavy so it resists wind damage. Roofs made of either of these two materials can be fire proof, durable, and long lasting.
Basically, tiles are made out of either kiln-baked glazed ceramic, or cast in concrete.
Tile roofs offer a highly durable roofing solution with beautiful appeal.
Tiles, like shingles, are available in a wide variety of colors and designs.
WOOD SHINGLES AND WOOD SHAKE
Wood shingles are typically made of cedar and usually treated with a fire retardant. The Los Angeles Municipal Code (91.1504.1) excludes them from the list of approved roofing materials that can be used in the City of Los Angeles (As well as most others). The ordinance restricts all wood roofs and does not differentiate between untreated or fire retardant. Split wood shakes are aesthetically pleasing and long lasting. Shakes, due to their rough look, are desired in certain architecture. They take longer to install than typical shingles and sometimes are installed for decorative purposes-with another roof underneath them when used for low sloped applications.
Wood shingled roofs are attractive and insulate, but they are also prone to problems. Since moisture effects all wood products, it is important to keep wood roofing dry, clean, and the underside of it ventilated. Leaves, dirt, and debris collecting on a wood roof retain moisture and should be cleaned off often. Adequate attic ventilation can reduce moisture build-up underneath the shingles, too. Applying chemical treatments to a wood roof will extend its life, but it is best to use wood that has been treated before it is installed to assure complete coverage. A wood roof will need regular attention-if you want it to last. Touching up problem areas with sealant helps, but don’t expect a wood roof to last more than 20 or 30 years.
Wood shingle and wood shake roof life expectancy varies considerably, depending on:
- Grade or quality
- Installation
- Ventilation
- The pitch or slope of the roof
- The roof’s sun and weather exposure
- The wood shingle or wood shake roof’s exposure to overhanging trees or debris that may hold water on its surface
- The roof’s exposure to shade that may promote moss or lichens growth
- Flashing material, installation quality, and details
Asphalt shingles come in two forms–fiberglass and organic–and are rated by weight. They can last from 15 to 25 years, depending onweight and installation.
Installation in warm weather is recommended as it helps to mold the shingles together. Taper sawn shakes are sawn on both sides. Tapersplit shakes are hand split on both sides. Hand-splitting increases material costs because it is labor-intensive. Some asphalt shingles are made to look like wood shingles.
SLATE
Slate ages very well on residential roofs. However, slate application is very specialized and few contractors excel in this type of installation.
METAL
Metal roofs are some of the soundest and most durable. Both shingle and panel metal roofs are extremely low maintenance. They carry a 20 to 40 year warranty, and many last for years longer. More expensive metal roofing products often pay off in the long run. A top quality metal roof, installed by a qualified professional, ensures that you are making an investment that can last a lifetime! Metal is lightweight and comes in an array of designs, shapes, and colors- including copper- achieving a myriad of architectural effects.
FLAT/LOW SLOPE
Flat/low slope systems, and the products typically installed with them have a shorter lifespan than Sloped/Pitched roofs-remaining in good condition for 10 to 20 years. Nevertheless, treating a flat/low slope roof with regular inspections and maintenance will enable it to last for a few decades. For more information, please click the links below.
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