In this video Greg discusses the problem of roof truss uplift. This problem occurs when the roof trusses expand and contract due to changes in temperature and humidity. This movement can cause the ceiling to sag and crack.
One solution is to install crown molding that is attached to the roof truss. This will allow the ceiling to move up and down without damaging the wall. Another solution is to install a block of wood between the wall and the ceiling. This will also allow the ceiling to move without damaging the wall.
For new construction, you can try installing a piece of metal that is attached to the walls and the bottom of the truss. This will prevent the truss from lifting and causing the ceiling to crack.
He recommends insulating the top cords of the trusses if this is creating the problem, to help prevent them from expanding and contracting.
Understanding Roof Truss Uplift
Roof truss uplift occurs when the bottom chord of a roof truss rises due to changes in temperature and humidity. This upward movement can cause stress on the ceiling and walls, leading to visible damage.
Common Causes of Roof Truss Uplift
Temperature fluctuations: Extreme temperature changes can cause the wood in the trusses to expand and contract, leading to uplift.
Humidity variations: High humidity can cause the wood to swell, while low humidity can cause it to shrink.
Inadequate ventilation: Poor attic ventilation can contribute to excessive humidity and temperature fluctuations.
Signs of Roof Truss Uplift
Cracks in drywall: Cracks in the drywall along the ceiling line can indicate stress from uplift.
Gaps between the ceiling and walls: If you notice gaps forming between the ceiling and walls, it might be a sign of uplift.
