Wood Trusses to Wood Beam Techniques

Nails

• The most common way of connecting wood trusses to beams is with nails. A 16-penny nail is driven at an angle through the bottom chord and into the top beam. The 16-penny nail is approximately 3.5 inches in length. The nail can easily be driven through the bottom chord and into the beam. The nails have a tendency to pull out over time. The expansion and contraction of the wood trusses caused by changing weather conditions can eventually displace nails.

Screws

• Wood screws are becoming a replacement for the nails. The screws are inserted through the bottom chord and into the top beam. Using wood screws to secure trusses to beams prevents the connection from loosening because of the expansion and contraction of the wood. Use the same length of screws as the 16-penny nail, 3.5 inches.

Brackets

• Another way of connecting trusses to beams is attaching a bracket, connector or metal strap to both components. The strap secures the truss to the beam without angling the nails or wood screws. The brackets come in many shapes and sizes to fit all truss designs. A strap has pre-drilled holes located on each end of the strap. One side of the strap is screwed or nailed to the top beam and the other side is secured to the roof truss. Using a bracket makes the truss-to-beam connection stronger and more secure.

Wood Pegs

• Originally trusses were connected to beams by notching out the beam, drilling a pilot hole and inserting a round wooden peg. This was most commonly used before nails and screws were widely available. This connection technique is still used by certain carpenters, but it is rare. A notch, the width and height of the bottom chord of the truss, is cut out of the top beam. The truss is inserted into the notch and a pilot hole is drilled through the beam and into the bottom chord. A wooden peg, the approximate diameter of the pilot hole, is hammered into the pilot hole and into the truss.