Roof Truss Strength

Such trusses are not hard to make.

Roof truss strength.

The bottom horizontal of the triangular truss form which corresponds to the joists in stick framed roofs is known as the lower cord. Trusses are designed based on 1 top and bottom chord size 2 size of web members 3 size of connectors at each chord 4 species of wood 5 pitch of roof. Excellent strength and span. These steel joints are needed to support the overall truss.

According to the american wood council the maximum span for rafters is about 30 feet and that s with a relatively low load of 20lbs per square foot. I d go to your local truss manufacturer and give him all the info i listed above and have him run it through his truss calculator. Roof trusses support a roof s weight by transferring the weight load downward and outward to the building s bearing walls. Long ago engineers learned they could add greatly to the strength of a roof by inserting compression members within the frames.

The only difficult part is cutting precise angles on the ends of the members so they will fit together tightly. The more complex the truss framework is the greater quantity of these joints will be required. A miter saw or motorized chop saw will come in real handy here. The same thing is true for the bridge of the truss.

The straight lengths of wood known as members that roof trusses built with are connected with intersections that distribute the weight evenly down the length of each member. It ll take him about 5 seconds and you ll know for sure. A roof truss is a triangular wood structure that is engineered to hold up much of the weight of the rest of the roof. Trusses are engineered to span larger distances than conventionally framed roofs.

The webbing effect of the truss members creates outstanding structural strength even though smaller lumber is used. Roof truss span tables alpine engineered products 15 top chord 2x4 2x6 2x6 2x4 2x6 2x6 2x4 2x6 2x6 2x4 2x6 2x6 bottom chord 2x4 2x4 2x6 2x4 2x4 2x6 2x4 2x4 2x6 2x4 2x4 2x6 2 12 24 24 33 27 27 37 31 31 43 33 33 46 2 5 12 29 29 39 33 33 45 37 38 52 39 40 55 3 12 34 34 46 37 39 53 40 44 60 43 46 64 3 5 12 39 39 53 41 44 61 44 50 65 47 52 70. He adds that connector plate manufacturers have done a lot of research in how the pattern is laid out to maximize the strength of the plate connection using various species of wood. They do this by means of top chords which are sloping members that extend from the peak of the roof to the top of the exterior walls at the eaves.

The upper angled parts correspond to the common rafters used in stick framing roofs. Truss spans can reach 60 feet. Since they transmit weight from the roof to the exterior walls none of the interior walls needs to be load bearing. Trusses are made up of four main parts.