Calculating the angles properly is a challenge for even the most experienced builder. When building roof rafters on site, a concern is that the cuts might not be as accurate. During this time, the home’s framing is often exposed to the elements, which can result in water and storm damage in severe weather. Roof rafters can take a week or so to construct on a 2,000 square foot home, depending on the construction crew size, the timber dimensions and the roof slope. There’s no lead time for rafters when the materials to build them are readily available. A team of two or three receives them on the roof, fits them, and nails them to the top-framing of the walls. They are either hand-lifted to the roof or raised by a mechanical lift. Installation takes a day or more on most homes. All the measurements, angles and cuts are digitally calculated and made by an automated precision saw. One key benefit of trusses is their dimensional uniformity. During the busy building season, advance time might stretch to eight weeks or more. You need to order your truss package two to six weeks in advance of when they’ll be needed. Trusses are also used on big homes or pole buildings. Standard trusses with a horizontal member at the base of the truss are used in homes with flat ceilings Scissor trusses employ slightly angled base members for use in low-slope vaulted ceilings. The main difference is that rafters don’t require base members and web-like cross members, and this gives you more design options such as spectacular vaulted ceilings with open framing or closed-in attic space. Rafters and trusses are used for the same primary purpose – to frame and support a home’s roof. Very large roofs are usually built with trusses – the largest spanning more than 60 feet. Larger projects up to 48 feet or so can be framed with either. Small projects – those with a roof span of less than 16 feet – are usually fitted with rafters. The trusses are rarely exposed because they don’t have the pleasing appearance timber rafters possess. Homes built using trusses usually have flat ceilings or ceilings that are minimally vaulted. This allows for an open ceiling design for aesthetic purposes or to maximize use of the space (see next). They don’t have to be built with a horizontal member connecting the base of the rafters on each side. Rafters, which are built on site, are more versatile and allow for more creativity in roof design. When larger timbers are used, rafters can be spaced further apart than the customary 16” (most common) or 24” that trusses require.Įven though trusses are built using 2”x4” lumber, their web-like design and closer spacing makes them strong and durable. When hand-hewn, they deliver a rustic or Western appearance. For open, dramatic ceiling structures, timbers 6”圆” to 12”x12” can be employed. Roof rafters can use 2”x4” lumber on small projects, but larger roofs often require thicker materials up to 2”x12” boards of various lengths. Trusses are generally fabricated by using 2”x4” dimensional lumber. They may have the same basic shapes, but roof rafters can use a variety of different sizes of lumber. Roof rafters and trusses can look similar, especially when built with dimensional lumber.
0 Comments
Leave a Reply. |