In previous years, roofs were constructed using rafters, which were built and installed onsite by a carpenter to connect the ridge board (roof peak) to the exterior wall plates and create a support for whatever exterior roofing method you choose. Today, rafters are becoming less popular because homeowners incur bigger costs in labour and lumber among many other reasons. This article discusses some of the considerations homeowners today must make when deciding what roofing system they should use.
1. Construction time
Constructing roof rafters, also called stick framing, takes significantly longer than setting trusses onto your house roof. This is because trusses come pre-built from the factory, and all that's left is setting them up onto your house. However, there is also an amount of time spent in building the pre-assembled trusses offsite, since they have to be custom-ordered according to your house plan and specifications. In this case, if you need a simple roof on a time-barred construction project, rafters have less lead time. The latter are prepared onsite, and hence need no extra allocation for transportation time to the site.
2. Project size
The cost of one method over another depends on the homeowner's budget as well as the magnitude of the project. Rafters may make sense when you're building a small, simple roof. In this case, the custom design, construction and transportation cost may not make economic sense in light of the entire project. Remote building sites may also face a challenge in transportation of pre-made trusses. In addition, you won't work up huge costs in workmanship/labour.
If you have a complex roof design involving several roofing styles, or building a larger house, you should definitely consider trusses. This is because trusses are often designed and made very precisely using computer-driven machinery under the supervision of skilled structural engineers. All factors are considered to ensure weight is evenly transmitted onto load-bearing external walls for a long-lasting roof. Using rafters will depend on the judgement of the building supervisor, which doesn't match the precision of using computer generated designs and products. A small error could have disastrous effect in the long run.
3. Material costs
Wood is an important and increasingly scarce natural resource, and hence it must be used sparingly. Trusses can help to save up on wood for roofing, since they consist of triangular-shaped lumber webs linked using tooth plate connectors. However, they lose nothing in strength and stability, even though far less wood is used for truss construction compared with rafters.
4. Flexibility in in-house design
Trusses reduce the need for internal load-bearing walls, since they can have high stability over longer distances and can transmit roof weights to exterior walls only. As a result, you're allowed to have more open floor plans rather than erecting walls out of necessity to help with weight-bearing.