Wood Truss History

TCS

THE HISTORY of WOOD ROOF TRUSSES –

The wood roof truss that we so commonly see today are frames of triangulated lumber joined together with galvanized metal roof truss connector plates, commonly referred to as metal roof truss plates. The shape of wood roof trusses has not changed over the years but the make-up, spans possible and the safety has changed.

The wood roof truss shape has been in use since man has used pieces of logs and then, centuries later, sawn lumber. In modern times, the first light wood frame roof trusses were built on the construction site using nailed boards or plywood gusset truss plates at the joints. Use of these early roof trusses offered longer spans, more cheaply, than un-trussed lumber but took a long time to build on the construction site. In 1952, in Pompano Beach Florida, after experimenting with plywood gusset truss plates and varying concoctions and combinations of glue, staples, nails and screws, the metal truss plate connected engineered wood truss was invented and patented.

The inventor, A. Carroll Sanford, founder of Sanford Industries, marked the beginning of the wood roof truss industry, that is still changing home, apartment and commercial building construction all over the world.

The day of the roof truss plate manufacturer had begun. Modern wood roof truss and floor trusses built with metal truss plates, clear-spanning between the perimeter walls, allows larger more open room designs, particularly in areas of great snow loads. This roof system proved to be faster and more cost effective than earlier practices, much less material and less labor cutting and fitting materials in the field. roof truss plates. Truss Plates, Pallet Plates

WOOD ROOF TRUSSES and FLOOR TRUSSES TODAY –

Wood trusses are widely used in single and multi-family residential, institutional, agricultural and commercial construction. Their high strength-to-weight ratios permit long spans, offering greater flexibility in floor plan layouts. They can be designed in almost any shape or size, restricted only by manufacturing capabilities, shipping limitations and handling considerations. roof truss plates.

The design and manufacture/fabrication of metal truss plate connected wood trusses is, in modern roof truss operations, accomplished by computer. In Design, the first decision to be made is the overall look of the roof or floor system to be produced followed by a decision as to the overall span. Then the computerization of the process takes over. Common standard engineering principles along with building code required roof, roofing material, ceiling, wind and snow loads, loading of the floor above, as well as any extraordinary loading or stress conditions are taken into consideration.

These technical details and a few others, are then entered into the computer. roof truss plates. An engineering drawing is produced by the computer detailing the forces that develop in each chord and web under the given design loads. Engineering specifications also include the truss dimensions and pitch, lumber sizes, species, dimension/size and grade of wood for each chord and web. The gauge, size and orientation of each metal connector truss plates is precisely specified as well as the size, strength and location of permanent bracing. roof truss plates. The resultant engineering drawings are supplied by the truss designer/manufacturer to the architect, engineer and to the building contractor. The carpentry contractor responsible for setting the woof roof truss in place, must also get a copy of the these truss drawings to make certain that the design conditions are met. roof truss plates. The strength and integrity of the wood roof truss depends on the integrity of its metal truss plate connectors. Stamped from light (16,18, 20) gauge structural steel coated with zinc, most metal truss connector plates have many integral teeth, 5/16 inch to 9/16 inch in length.

Normally, there are eight teeth per square inch. These roof truss plates are sized according to the level of stress that they have to transfer between members of the roof truss, as sized by a wood roof truss engineering software, such as Component Designer. roof truss plates. Trusses are, in the USA, most often made with southern pine dimension lumber, however, from time to time, and in some areas, Douglas fir and the woods of the spruce-pine-fir (SPF) group are used. roof truss plates. Typically the truss manufacturing process starts by carefully cutting nominal 2″ (actually 1-1/2″) thick members so that they are exactly the specified length and have the exactly the correct angles at the ends. Many truss manufacturers use computer-driven saws that produce multiple cuts quickly and precisely.

The species, the size and the grade of lumber for each piece on the component cutting list (cut sheet) is based on the magnitude of force that each must resist while under potential maximum design load. Highly stressed, top and bottom chords are usually made of lumber that has been stress-rated, either visually or by machine, with rules mandated by code and industry association, to ensure specified performance. The webs of the wood truss, because they are usually subjected to lower stresses, are more often made from a lesser grade of lumber, such as #2, #3 grades. roof truss plates.

What is a Roof Truss?

A roof truss is a rigid, strong frame work made up of wood members, such as 2” X 4”s, fastened and held together by metal truss connector plates. This framework accounts for the shape of your roof and supports the roofing materials. Roof trusses are designed according to ancient geometric principles. Many of the bridges you drive over were designed using the same principles. roof truss plates.

Are Wood Roof Truss Systems Superior To Conventionally-framed Systems?

All roof systems are adequate if properly designed, constructed and installed. Unfortunately, not all roof systems meet those criteria. roof truss plates. In our opinion, wood trussed roofs are superior due to professional design, high quality materials, uniformity of size and pitch, and the fabrication techniques used. roof truss plates.

Why Is A Wood Roof Truss Trussed Roof Better?

Lumber used by quality truss manufacturers conforms to strict state, local and national building design criteria. Lumber for trusses is cut by machines that are mathematically calibrated and set to produce high accurate cuts. This helps eliminate gaps when truss members are joined. Because trusses are manufactured with great precision in jigs, multiples of the same truss are identical in size, assuring uniformity throughout your roof system. Truswal, Trusplus In conventional building most carpenters can cun and build a roof. But, much is left to chance and the builder’s opinion. However, most wood truss roof systems are designed by engineers or architects to fit your specific roof system and conform to applicable building codes. Most wood roof truss s are fabricated under ideal shop conditions and therefore, are not usually subjected to a great deal of exposure to inclement weather until delivered to the site. Your house is closed in more rapidly with wood roof truss es, thus reducing the time interior walls and floor are exposed to the weather. Wood Roof truss es are designed to eliminate deflections. You get even, level ceilings and less chance of plaster or drywall cracks.

 




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