When the house was built a couple of the engineered trussses were cut to allow for a chimney. After 34 years a couple of the Z braces on two trusses started buckling and the roof above them has a slight sag. The ceiling joist remained straight. The trusses are soundly fastened to the chimney and there isnt any evidence of the chimney settling also there is no problem with the roof on the opposite side of the chimney. This was first noticed about 4 years ago. My fix was to place a beam made of two 2x6s screwed together across 4 good trusses and the 2 effected trusses and installing two lolly colums from the beam to the point of the rafter point on the trusses in the middle of the sag. I gradually extend the lolly colums over a period of about 3 years and at this point the warped bracing and sagging spot in the roof are now straight. I want to remove the added bracing. I am guessing that there was a change in load distibution due to cutting the trusses for the chimney and more load ws placed on these braces than they were designed.I was thinking about screwing strips of plywood to the affected bracing to make it more rigid and possibly doing the same to the rafter and joist portions of the effected trusses. I gave some thought to replacing the effected bracing but the gussets that hold it in place also splice together sections of the rafter. Any opinions and advice would be appreciated.
Jimmie