Is This an Allowable Repair?

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Issue #10210 - January 2017 | Page #28
By Glenn Traylor

There is nothing worse than running a truss out the door and then realizing one of the truss members is broken. The question is – can I make a quick fix using a connector plate? The short answer is – no. But there are many who may not realize that specific engineering is required for these types of repairs.

Broken chords can often be analyzed by running the break as a splice – but without special engineering knowledge, this sort of decision should not be made on the shop floor of the truss plant. As the truss is rolling through the finish press, the twist, warps or cups in the lumber can cause the wood to straighten under pressure and then crack to relieve the internal forces. This causes breaks in the lumber across parallel to the grain, and sometimes across the grain, creating defects that must be addressed before the trusses can be used.

Keep a watchful eye out for cupping and bows, particularly in wide boards. Watch these after they are pressed to make sure damage has not occurred.

If damage is detected, pull the truss off line and remove the damaged lumber or seek engineering to facilitate a repair. Due to the nature of these sorts of situations, it is usually more advantageous to replace the defective lumber.

Glenn Traylor

Author: Glenn Traylor

Structural Building Components Industry Consultant

You're reading an article from the January 2017 issue.

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