Roof Truss Design

Read on to know more about the roof truss design, their advantages and disadvantages…
A roof truss is a very strong and stable frame that is made of wood and is held together with the help of metal connector plates. It is a relatively new design that has also been used to provide support and shape to bridges. It is also commonly described as an open web type of design.

Roof truss designs have been considered as a wooden engineering marvel that is highly cost effective and is well acclaimed in the market as a means to provide low cost roofing with a high quality that can be used in all commercial and industrial buildings where fire resistance is not a requirement.

The most common roof truss designs are made using ordinary softwood of sizes 2x4" or 2x6" which are held together with the help of joints and a number of wooden and metal fasteners. It is a very delicate piece of structure when it is not in its upright position and can be easily damaged if handled clumsily.

The important points to take care of during the construction of the truss roof is the peak of the truss, clear span, pitch, the overall length and the overhang. Ensuring that the lumber is not too moist and is adequately flame retardant and the metal connectors that are uses are rust free is a very important step too.

Advantages of Roof Truss Designs

The design of the roof truss designs is such that it is very complex and because of the critical nature of the joints, they are usually not assembled at the site. Rather, they are assembled at the manufacturing plant and are trucked to the final destination. Despite the complex structure and the fact that these structures appear very fragile, these structures are extraordinarily strong once they are erected mainly due to the amount of sophistication that is put into its engineering.

Roof truss designs are a product of the computer age. Over a hundred years ago engineers would calculate the amount of stress and built these roofs intuitively, but at that point of time, roof truss designs were an expensive affair not feasible for residential or commercial constructions that were to be built on the budget. The computer has helped change everything. Today, you can walk into any one of the local lumberyard with a design of the building on your palm and can watch the technician key in the specifications and a few seconds later, the printer prints out the design with every piece of lumber identified complete with the joint design and an estimated cost.

The wooden trusses work out cheap but offer great strength as they have been engineered in a manner that every piece of wood in the roof structure offers support and strength. To further enhance the strength of the structure, special metal plate with punch stamped were invented. These fasteners are user to join pieces of wood together using a hydraulic press.

Disadvantages of Roof Truss Designs

Because of the complexities involved in building the roof structures with multi prong fasteners with the help of hydraulic equipments, these structures cannot be built at site of the building. Hence, these roofs are designed at a plant and have to be transported to a location of the building. Transportation itself raises a major drawback. Once the trusses are assembled, they can get a little too big. Sometimes they are too big for a truck. Specially designed truss trailers have to be used to haul the structures around.

The conventional truss design leaves a large volume of attic space unusable as these structures create a web of wood framing that leaves no possible space of using it as a utility. Further, because of the entangled wooden framework, the aesthetic appearance of the roof is very low. No doubt, it can be covered up with wooden trim, but it is an additional cost.

Lastly, these wooden roofs can be very susceptible to fire. However, an alternative is available these days and the lumber can be replaced with light gauge steel frames which will not only be more resistant, it will also be more robust when compared to wood roof trusses

I hope that this article has provided sufficient information and has shown both the sides of the coin with regards to roof truss designs. However, before you make a final decision, it is imperative that you talk to your contractor or builder to analyze the feasibility and the cost effectiveness of using a truss roof for your building. Happy building!
   By Ranjan Shandilya
Published: 1/15/2008
 
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