PDA

View Full Version : Floor Truss End Support



James Duffin
07-18-2011, 11:57 AM
Does anyone know of any application where it is permissible to nail floor trusses to a main beam with no hanger or support from below? All of the info I find says there has to be 1 1/2' of bearing surface like any other wood joist. It looks so blantly wrong to me I think it must be right and I am missing something. The house is 14 years old and has had two owners. The second is now the seller.

http://www.ufpi.com/literature/ojguide-74.pdf



Here is what the NC Code says about bearing surfaces:


RS02.6 Bearing. The ends of each joist, beam or girder shall
have not less than 1.5 inches (38 mm) of bearing on wood or
metal and not less than 3 inches (76 mm) on masonry or concrete
except where supported on a 1-inch-by-4-inch (25.4 mm
by 102 mm) ribbon strip and nailed to the adjacent stud or by
the use of approved joist hangers.
RS02.6.1 Floor systems. Joists framing from opposite
sides over a bearing support shall lap a minimum of 3
inches (76 mm) and shall be nailed together with a minimum
three 10d face nails. A wood or metal splice with
strength equal to or greater than that provided by the nailed
lap is permitted.
RS02.6.2 Joist framing. Joists framing into the side of a
wood girder shall be supported by approved framing
anchors or on ledger strips not less than nominal 2 inches by
2 inches (51 mm by 51 mm).

Michael Avis
07-18-2011, 08:49 PM
The first picture showing the bottom chord sitting on a treated wood plate seems ok. The second picture is completely wrong. Trusses are engineered to bear on the chords, sometimes top, sometimes bottom. On these trusses the two chords are the same length so they are obviously intended to bear on the bottom chord.

Trusses, especially wood trusses are never intended to bear on the web, (the pieces that connect the two chords together). In the photo you supplied it appears as though the framers spiked a couple nails through the end web member into a carrying beam. This is fine only temporarily to support the dead loads only and to hold things in place just until the sheathing is installed but NEVER to support live loads.

Proper saddles, straps or hangers should be installed now and these should be sized by a PE. This is a disaster waiting to happen. The bottom chords are ineffective as installed and the trusses' ability to carry loads is greatly reduced.

Somebody needs to take these boys' hammers away. Hope this helps.

Bruce King
07-18-2011, 09:27 PM
Did you check to see if the top chord was extended and bearing on top of the beam?

See this doc, some open web trusses can be supported with the top chord.

http://www.trusscomponents.com/pdf/Floor%20Truss%20Guide.pdf

James Duffin
07-19-2011, 03:19 AM
thanks for the replies guys...