Truss Repairs, Never Field Alter a Truss
Mike the Pole Barn Guru Writes:
I spent years (and years) in the prefabricated metal connector plated truss industry. I cannot begin to count the number of times we saw trusses altered in the field without having consulted us beforehand. Without using any fingers, I can also count the number of times these in-the-field truss repairs were done adequately so as to be supported by engineering.
ZERO
NADA
ZILCH
NEVER
Starting to sound like one of those Capitol One television commercials?
Reader ANN from WELLSTON writes:
“We erected a 24’×24’metal garage with pre-manufactured trusses. We also installed a commercial roll up door. The truss over the door canister needed to be altered. The building inspector says we need to reinforce that truss. How do we do that?”
Mike Responds:
To begin with – KUDOS to the Building Inspector who caught a truss alteration which should never have been done without engineering.
Hopefully what has been done to the truss does not render it as being unable to be repaired.
The best place to start is with the manufacturer of the trusses. Take numerous photos of what has been done to the truss, as well as providing a sketch giving all dimensions of the alterations.
A typical truss repair might call for a combination of dimensional lumber and plywood gussets “scabbed” beside some or all of the remaining chord and web members to make up for the cut or lost members. The repair design should include material dimensions for added members, plus a detailed fastener schedule showing the size, number, and placement of fasteners.
If the truss manufacturer is unable to provide a repair, you will need to hire a registered professional engineer to examine the truss and determine if an engineered repair is even a possibility.
All of this is why I strongly encourage everyone who is considering a new post frame building to only invest in a building kit package which has been designed by a registered professional engineer – it avoids a plethora of challenges, grief and expense down the line.