Truss Roof Construction

Truss roof construction speaks to roof truss basics and what is a roof truss.

To define roof in its simplest terms it is understood to cover the uppermost part of a building and protects the building and its contents from the effects of weather especially rain as well as against cold, wind and rain but may admit light.

The characteristics of a roof are dependent upon the purpose of the building that it covers, the available roofing materials and the local traditions of construction and wider concepts of architectural design and practice and may also be governed by local or national legislation.

Design Elements of Truss Roof Construction

The elements in the design of a roof are the material, construction concept and the durability of such.

Material

There are many materials available for roofing purposes for modern structures such as plastic, fibreglass, concrete, various shingles and metal.

Shingles are a popular choice and can be made from asphalt or fibreglass and these composition shingles are available in large selection of types, makes and colours which are versatile and easy to install. They are easy to install and even may be installed over an existing roof. Requiring low maintenance and may be walked on without causing damage as well as offer Class A fire protection. A drawback is that they may blow off in high winds.

Wood shakes offer a wide range of colour, width, thickness, shape and wood. They have energy efficiency capabilities by helping to insulate the attic and allow air to circulate through the small openings which are under the felt on which the wooden shingles are laid. The drawback is the shakes require maintenance and repair and have a short life cycle as mold, rot and even insects can be a problem.

Clay tiles are suitable for homes modern homes or those designed in a southwestern, Italian or Spanish architectural design. Tile lasts a very long time, longer than the material the tile is mounted on. It is available in a variety of colours, types, styles and brands and it will not rot or burn or be affected by insects. Unfortunately it is heavy requiring extra roof support to maintain it. If the clay is kiln fired the tile colour will not fade however if surface coloured it will fade in time. The tile is fragile and should not be walked on which makes maintenance difficult. It costs more and is more demanding than other tiles to install.

Concrete tiles are now available as a roofing material as all of the above mentioned products are now being manufactured from a variety of fiber reinforced cement products. Some are coated with plastics, enamels, or thin metals and made from recyclable materials. These tiles have a long lifespan, require low maintenance, offer good fire protection and are resistant to rot and insects. Concrete is more expensive than most roof materials and there are a wide variety of style and colour.

Metal roofs are available in a wide variety of designs, textures, styles and colors and is available in traditional vertical seam profiles or can be manufactured to resemble wood shake, slate, shingles or clay tiles and can complement any type of architecture.

These roofs are durable and are resistant to cracking, shrinking and eroding, metal is virtually a maintenance-free roofing material that lasts. They can withstand extreme weather conditions including heavy snow loads, hail storms and wildfires and feature interlocking panels, which resist and eliminate damage from high winds. Residential metal roofs have long-term warranties, often up to 50 years.

Metal roofs are energy and cost efficient and can save homeowners up to 40% in annual energy costs, depending on geographical area and have a lower life cycle cost compared to other roofing materials. Metal roofs increase the value of a home and in fact, a metal roof adds to a home’s overall value. Many insurance companies give discounts of up to 35 percent to homes with metal roofs.

Metal roofs are energy efficient and now utilize reflective pigment technology, which results in overall home energy efficiency and are made from 30-60% recycled material.

Hot mop asphalt roofs are used in the most part for commercial applications but are also seen in well drained flat or semi flat residential roofs. It is much less expensive than other roofs and is durable if properly applied. It is not attractive and is often covered with a layer of storm. When being installed it adds a lot of pollutants to the air and for this reason may not be allowed in some areas.

Construction of Truss Roof Construction

The construction of a roof may be determined by its method of support and how the underneath space is bridged and whether or not the roof is pitched. The pitch is the angle at which the roof rises from its lowest to highest point. In areas subject to rain and snow roofs must be constructed with adequate pitch.

Most North American domestic architecture, except in very dry regions, has roofs that are sloped, or pitched. Although modern construction elements such as drainpipes remove the need for pitch, roofs are pitched for reasons of tradition and aesthetics.

There are two parts to a roof, its supporting structure and its outer skin, or uppermost weatherproof layer. The roof structure is generally supported upon walls, although some building styles, for example geodesic and A frame blur the distinction between wall and roof.

The supporting structure of a roof usually comprises beams that are long and of strong, fairly rigid material such as timber and since the mid-19th century, cast iron or steel. Timber lends itself to a great variety of roof shapes. The timber structure can fulfil an aesthetic as well as practical function, when left exposed to view.

With continual improvements in steel girders these became the major structural support for large roofs, and eventually for ordinary houses as well. Another form of girder is the reinforced beam, in which metal rods are encased in concrete, giving it greater strength under tension.

Durability

The durability of a roof is a matter of concern because the roof is often the least accessible part of a building for purposes of repair and renewal, while its damage or destruction can have serious effects on the building as a whole. The durability of a roof is dependent on the roof form and roof shape which dictate the required roof parts.

The shape of roofs differs greatly from region to region. The main factors which influence the shape of roofs are the climate and the materials available for roof structure and the outer covering.

Types of Roof

The basic shapes of roofs are flat, skillion, gabled, hipped, arched and domed, There are many variations on these types. Roofs constructed of flat sections that are sloped are referred to as pitched roofs (generally if the angle exceeds 10 degrees). Pitched roofs, including gabled, hipped and skillion roofs, make up the greatest number of domestic roofs. Some roofs follow organic shapes, either by architectural design or because a flexible material such as that is used in the construction.

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Roof Deck Designs

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Between Deck Roof Insulation

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Roof Edge Drainage

Panel Metal Roofing

Steep Roofs

Wood Shingles Shakes

Asphalt Composite Shingles

Shingles and Tiles

Architectural Sheet Metal Roofs

Roof Energy Considerations

Cool Roofs

Green Roofs

Photovoltaic Roofs

Roof Building Codes

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