Roof Truss Information
Why pre-fabricated nail plated timber trusses?
Because of the costliness and limitations to bolted trusses, requiring an engineer’s design over certain spans, the popularity and effectiveness of monoplanar, nail plated trusses, has increased over the years.
The strength, reliability and the saving in cost and time, makes it an obvious choice with the demands being faced in the industry.
Who should erect roofs?
Despite the cost effectiveness of pre-fabricated timber trusses, the complete roof structure still remains an expensive and critical part of a building. It is then senseless to employ an unqualified person to erect such an important and expensive structure.
Apart from the practical skills level of an erector, the technology involved in the design of timber structures, requires the roof erector to be at least knowledgeable in the terminology being used in the roofing industry.
- He must be able to read, understand and interpret the design output (drawings) sent to site.
- He must understand the importance of bracing, and why it is critical in the erecting of timber roof structures.
- He must be aware of the limits on remedial work, and when to employ the help of an engineer.
- He must be aware of the characteristics, properties & uses of timber, as well as the consequences of loads applied to a timber structure.
- He should have an understanding of axial forces (tension and compression forces), sheer forces, bending moments and know what the “effective length” or buckling length of slender members are.
- He should know what stress reversal is, and how to compensate for those forces. He should have an understanding of why bracing is important, and the different types of bracing used for various applications.
- He should understand the necessity for trusses to be straight and plumb, and why they are spaced according to certain truss centres, for various types of loads applied to them.