How To Make 2x4 Floor Trusses

Maximum deflection is limited by l 360 or l 480 under live load.

How to make 2x4 floor trusses.

Build a fink truss to bolster a floor roof or deck. While they flex more than i joists they flex less than lumber trusses and use less wood. Open web floor trusses are constructed with 2x4 boards on the top and bottom with a web of diagonal boards in the middle secured with metal plates. The multiple bearing conditions make matching existing floor heights much easier when using floor trusses.

Use of manufactured roof trusses can dramatically cut labor costs when framing a gable roof compared to building rafters. Spacing of trusses are center to center in inches. Most spans are typically 10 to 12 feet so we typically use 2x8 or 2x10. Fink trusses were originally invented for the purpose of beefing up bridges but many contractors now use them to increase the strength of interior structures.

Live load is weight of furniture wind snow and more. Basic lumber design values are f 2000 psi f 1100 psi f 2000 psi e 1 800 000 psi duration of load 1 00. Maximum floor joist span for no. There are online span calculators available that tell you the maximum span for.

1 ft 0 3048 m. Floor truss span tables alpine engineered products 17 these allowable spans are based on nds 91. I joists offer only one bearing. 1 psf lb f ft 2 47 88 n m 2.

Trusses can be constructed with smaller sized lumber than rafters and often their cost is not significantly higher than normal rafters. In a fink truss the internal joists are arranged in a w shape ensuring even weight distribution from one end to the other. Floor trusses offer four different bearing conditions for a wider variety of uses. Raised floor living in conjunction with southern forest products association developed a table to help understand how trusses are built.

Trusses are beneficial in that the open spaces in the middle make it easy to run utilities through them. Bottom chord bearing bottom chord bearing trimmable ends top chord bearing and mid block bearing are all available. 2 grade of douglas fir are indicated below.