Standard Spacing For Roof Trusses

The run or the base number is 12 inches.

Standard spacing for roof trusses. A 10 8 6 and 4 spacing between trusses has been the standard for most types of construction for years. Although the standard spacing of roof trusses may be the same as that of rafters with 24 inch spacing being a common option the design of a truss may allow for the use of a lower grade of lumber than would be required for rafters with comparable spacing and span. Engineers have since determined however that the physical design of a post frame building will allow for standard spacing as great as 12 feet from the center when using high quality metal connector plates and lumber. With this design change roof trusses could be placed 12 feet apart making it possible for roofs to support the loads to which they would be subjected.

Most are spaced between 18 26 inches apart. Almost all residential trusses use this spacing. Typical standard the typical standard for the spacing on the roof trusses is 24 inches. These standards are as follows.

What dictates the truss design is the roof design snow load typically 20 or 30 psf in most of the u s. The trusses should be a little longer than the exact width to allow for overhang and you will need sufficient trusses to mount across the length. The rise will be the elevation change over the 12 inches. I ve had roof truss manufacturers try to convince me it is impossible to place wood trusses at spacings of over every 4 feet.

This is the distance between trusses. Spacing a live load deflection limited to l 240 maximum and use lumber properties as follows. Putting the trusses into place. Keep in mind that the higher the pitch the steeper the roof.

Their defense is our engineers will not allow us to. As most building these days are using those pre made trusses on the roof 24 inches become the main size for any roofing construction when it comes to its truss installation. Once you ve calculated the number of trusses you will need you should purchase the lumber. 2x4f 2000psif 1100psie 1 8x10 2x6f 1750 psi f 950 psi f 1900 psi e 1 8x10.

Spaced sheathing or 1x boards may be reduced slightly. Allowable spans for 2x4 top chord trusses using sheathing other than plywood e g. This is most likely the standard size that you will find on pre made roof trusses. But in general it doesn t matter if the truss spacing is at 12 16 or 24 inches.

There is a misconception that spacing trusses every 16 on center is better because it will be strong than the average 2. While this can be true it is not always accurate unless in some high stress situations. The standard roof truss spacing is 2.