How To Read Roof Truss Plans

Installation details hanger schedule job information on center spacing and special truss locations are op tional information that may be included on the truss placement plan by the truss manufacturer.

How to read roof truss plans.

Just remember the acronym. Your top chords can protrude beyond the bottom chord anywhere from 1 3 feet 0 30 0 91 m. Truss technology in building how to read a truss placement plan a truss placement plan is a layout drawing identifying the assumed location for each truss based on the truss manufacturer s interpretation of the construction design documents. 4 7 12 would be the dimension 4 7 12 16 or 4 7 3 4.

This stands for f eet i nches s ixteenths. The first thing to check is what scale the roof is drawn in. Trusses that are mistakenly installed backwards or upside down cannot support the same amount of load as a correctly installed truss. Avoid errors by taking the time to review your truss design drawings.

Trusses may have symmetrical profiles but the loads they carry may not be symmetrical. 12 truss height the height of the truss from the top of the bearing to the top of the top chord trusses with multiple levels of top chord will have multiple truss height dimensions feet inches sixteenths 13 plate size orientation and type plate size in inches. 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. Live loadany temporary applied load to a floor truss chord.

The next thing to determine is the roof pitch see how to determine roof pitch the easiest and most accurate method to measuring a roof plan is to square everything off. In this drawing a 1 8 scale ruler is being used. The roof below is drawn in 1 8 scale this means that if using a regular tape measure that 1 inch would equal 8 feet. On some roof trusses the 2 top chords extend down over the edges of the bottom chord creating a built in overhang.

Truss design drawings have long been a source of confusion for contractors design professionals and building inspectors alike. The answer is a convention of the truss producing industry. L d ratiothe ratio of the truss span l to its depth d both dimensions in inches. I don t know if it s the result of growing up as an only child but i am a complete sap for any creature with big eyes feathers scales or fins that needs a loving home.

The two lines denotes the direction of the plate. If you think you d prefer an overhang style truss adjust the measurements for your top chords accordingly. So for example a dimension string that reads. How to read roof truss planshow to how to read roof truss plans for i love animals.