Lumber Size For Roof Truss

Allowable spans for 2x4 top chord trusses using sheathing other than plywood e g.

Lumber size for roof truss.

Trusses must be designed for any special loading such as. The truss is a framework consisting of rafters posts and struts which supports your roof. 1 psf lb f ft 2 47 88 n m 2. One will like to use a 2 6 1 yellow pine with a certain mending plate where another will like to use a 2 4 msr 2400 with an extra web.

Spaced sheathing or 1x boards may be reduced slightly. There s already been mention of using a prefab set up when appropriate and you can always attempt to negotiate a lower labor fee for larger projects. A stick framed house used 20 643 board feet of lumber while a component framed house including roof trusses used only 15 052 board feet of lumber. They are designed at a 4 12 pitch to be spaced 2 foot on center.

A 4 12 pitch means that the roof rises 4 inches for every 12 inches of run. The room size will vary depending on the width and slope of the truss. It is always better to have a large rafter rather than be concerned with a sagging roof. 2 are indicated below.

It is strong but shallow maximizing the use of lumber using available and ordinary lumber sizes. If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center. Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no. The important point to keep in mind when you use your truss calculator is that every truss calculation is completely unique and is based on the size of your roof and its specific dimensions.

Dead load weight of structure and fixed loads 15 lbs ft 2. 2x4f 2000psif 1100psie 1 8x10 2x6f 1750 psi f 950 psi f 1900 psi e 1 8x10. 1 ft 0 3048 m. That is 25 less lumber which means more money in your pocket as the builder and more money in the pocket of the homeowner.

I hope this clears up the muddy water of truss design. Visit the roof framing page for more information on cutting roof rafters and visit the roof pitch calculator for determining rafter lengths based on rise and run. A gambrel room in attic truss also provides extra living space while giving your roof a barn like appearance. Every truss designer has his own signature style.

Pre manufactured stock trusses are constructed with spruce pine fir spf or southern yellow pine syp lumber. If the truss is designed in a way the engineer will approve it then it doesn t matter the lumber size that was used. Gable room in attic trusses provide an economical way to add extra living space to your home or garage. Live load is weight of furniture wind snow and more.

Maximum and use lumber properties as follows.