A floor truss is a geometric design using wood members fastened together with metal
connector plates to form a structure which supports a given floor load.
Are floor trusses something new?
No, W&W Truss Builders has been manufacturing Building Components for over 25 years.
Floor trusses have been around for quite some time.
What is new about them?
Almost universal acceptance of 4" x 2" floor trusses as an excellent method of floor
Why have they become so popular lately?
There are numerous answers to this question, however, the most important are the
many cost saving benefits.
What are some of the advantages of 4x2 floor trusses?
Longer clear spans.
In many cases, elimination of support beams.
Virtual elimination of squeaks.
Reduced sound transmission.
Lower costs for sub-contractors.
Greater nailing area for sub-flooring.
Finished basement ceilings.
Elimination of unsightly electrical wires, plumbing, and
Speed of installation.
Size of rooms not limited by joist span tables.
How does a 12" deep floor truss spaced 24" on center compare in span to a 2" x
8" joist 16" on center?
Using a 55 psf load for the 4" x 2" floor truss and a 40 psf load for the 2" x 8"
joists, you can span approximately 17 feet with the trusses and 13 feet, seven inches
with the 2" x 8"s, depending on the grade of lumber used.
Do floor trusses deflect a lot?
NO! Floor trusses are not permitted to deflect more than L/360 of the span length
when under full load. To offset even this tiny deflection, camber is built into the
truss and strong backs are installed to help strengthen and reduce vibration.
How are floor trusses manufactured?
In shops specifically set up to produced uniform, quality floor trusses. Trusses
are assembled and clamped in jig tables. Metal connector plates are then either rolled
or pressed into the truss at the joints using special truss manufacturing equipment.
After the truss is fabricated, clamps are released and the truss is ejected from
Are floor trusses designed by the trial and error method?
No! Floor truss configurations are designed and certified by either a registered
engineer or registered architect.
What does an engineer or architect do with floor trusses?
Many things, however, basically they analyze the structure for span length, depth
of trusses permitted, and loads that the trusses are to carry. They also evaluate
special conditions such as stair and chimney openings, cantilevers, placement of
exterior and interior walls, etc. Then, the truss is designed reflecting type of
material, web placement, and plate sizes so that the truss meets all conditions requested.
Are floor trusses easy to install?
Yes! particularly on single story structures where the trusses can be erected and
placed manually. On multiple story structures, a crane is usually used to lift the
trusses to the desired height.
Note: Crane service is available, call our office to coordinate service with your
Are floor trusses heavy and unwieldy?
No, the approximate weight of a 12" high floor truss is five pounds per linear foot.
Therefore, a 20-foot truss that is 12" deep would weigh about 100 pounds - a weight
easily managed by one or two men. In addition, because of the open web design, there
are always ample hand gripping areas.
Is cross bridging required?
A 2" x 6" continuous "Strongback" is used in place of cross bridging. This helps
distribute the load to five to seven trusses, instead of only two to three trusses
as bridging does.
Note: Bridging and bracing are not the responsibility of the truss designer.
How much nailing surface is available on the trusses?
Because the lumber is used flat, both the top and bottom chords of the truss have
3-1/2" of nailing surface the full length of the truss.
Are stairwell openings difficult to do?
No. Several methods can be used to address stair openings. Consult W&W Truss when
stair openings are a consideration.
Do contractors and builders like floor trusses?
Like anything different or new, the first job ordered may produce some skepticism.
But after that, few contractors or builders return to the use of floor joists. New
innovations like 12" trimmable ends make floor truss easy to modify in the event
of unforeseen framing conditions.
How about the ultimate consumer?
Builders who use floor trusses often state that consumers are delighted their basements
are void of beams, posts, etc., and that in effect are complete living areas.
What steel is used in the connector plates?
The only steel permitted for use is metal connector plates by the Truss Plate Institute
and all government regulatory agencies is top quality, prime galvanized steel. No
seconds or reject steel is permitted.
How do we know the firm we are buying floor trusses from is qualified, reliable
W&W Truss Builders has been servicing our customers for over 27 years. We pride ourselves
in the quality of our product. You have our assurance that you will be entirely satisfied
with our product, or we'll be there to help you.