Roof Trusses are engineered building components designed to carry the roof load to the exterior walls of the house or structure or to a designed load bearing point.
The modern truss is built with less lumber and poorer quality of wood than 40 years ago.
In early to mid 80’s something new was happening to the houses.
In the dead of winter the building contractors were getting complaints of cracks on the top floor of the house where the walls meet the ceiling, and only on interior walls.
If the trusses went front to back the cracks would be the worst in the center following the center wall left to right, and the crack at times were more like gaps 1”– 1 1/2” the industry was troubled by the problem saying that the contractors was putting to much insulation in the attic causing a large fluctuation in temperature in the truss members it’s self making the truss to pull the bottom cord of the truss up by it’s self.
The truss manufactures remedy was to go in and lag bolt the truss down to the top plates of the interior walls.
The next year the cracks and gaps were gone Great- hold that thought, then the calls were coming in that the walls were not nailed down to the floors and you could see under the wall into the next room.
Trusses are very powerful pieces of engineered wood. They have lifted walls and pulled the nails with the walls.
The truss manufactures remedy was this time not to nail the sheetrock to the truss within 16” of the wall but instead put block on top of the wall between the trusses and nail to them instead.
The result is every year your trusses flex up and down making the sheetrock and insulation to do the same. Down the road you will find nail pops on the ceiling from 12-30” out from the center wall and your sheetrock will be sagging.
For my business I solved the problem by having the trusses designing then having the truss manufacture up size the top cord of the truss by 1 size larger board.
Example if the trusses called for a 2×4 top cord I required a 2×6 top cord for my needs, the cost was about $250.00 per house but no more call back.
So in retrospect what has happened to the truss industry they are trying to keep the price of trusses down and using cheaper quality wood.
Don’t worry the truss won’t fail it’ll just cause headaches and problems for the contractor and you the home owner watching the contractor scratch his head not knowing what to do or how to fix it.