Peeling Truss Plates

When truss plate manufacturers test their plates to come up with design values, one of the tests they perform is for "Lateral Withdrawal Resistance". Lateral withdrawal resistance refers to the truss's ability to resist "plate peeling".

As a result of our investigations it has become more apparent that the problems of peeling truss plates are more widespread than earlier anticipated. From 1970 until the late 90’s a locally produced plated branded as Steelfast was used extensively.

The tooth design used in the manufacture of these plates has proven to be the poorest performing of all plates showing failure or extreme peeling after a a period of around 10 – 12 years. Early detection of this movement can allow effective remedial repairs to be carried out. However if not detected the trusses may fail causing roof collapse.

Incorrect assumptions

• Only Steelfast plates peel
• Only heavy roof loads such as tiled roofs are effected
• Peeling only happens on large span trusses
• Cut roofs are don’t exhibit any structural issues

Some Warning Signs of Plate or Truss Failure

• Dip in the ridge line
• Waving over the roof tiles
• Waves in the ceiling line
• Dipping or popping of cornices
• Eaves being pushed away from brickwork
• Bow in the fascia and gutter line