Trusted Mold Inspections & Environmental Testing in Cote-Saint-Luc, QC

Truss Uplift Simply Explained Due to the unseasonable below average cold winter temperatures, I thought I would repost a blog..Truss Uplift. Cause Or Concern? Simply explained, Truss uplift occurs when the upper chord of a roof truss elongates, thus bowing up the lower cord. Like when you pull back the Bow string on a Bow to place an arrow. The visual effect of truss uplift. The walls in the center of a home remain in-place while the section of the ceiling below the walls, the attic flooring structure slightly rise leaving a gap, or the wall/ceiling drywall tape appears to be on an angle or pull away from the wall, as in the image above. The cause of Truss Uplift, a mixture of elements. Temperature and (RH) Relative Humidity in the attic. Lower attic truss chords are buried beneath a blanket of insulation allowing them to remain warm and dry. Exposed truss chords absorb ambient RH/water vapor, and relate to the surrounding temperature. Under the right conditions of Temperature & (RH) water vapor, the upper chord of the attic roof truss elongates, thus drawing a lower chord upwards bowing the chord as it elongates. The result. A detachment of the ceiling a lower chord rests upon. Concern? While the appearances of truss uplift may resemble a major defect, this is simply not the cause or concern. While the true cause of this anomaly has not had a wide analysis among leading experts, the consensus is fairly consistent. Truss uplift is primarily a cosmetic issue.