Effect of roof-edge parapets on mitigating extreme roof suctions

Very high intermittent suctions have been found to occur near corners of low rise building roofs. This paper investigates the effectiveness of parapets mounted at the roof-edge on mitigating these high suctions. The study included full perimeter parapets, both solid and perforated and parapets placed only at the ridge and the corner zones. The parapets used in the study had a 0.2 m full scale height which is more feasible for installation on typical homes than the taller parapets that have been considered in previous studies. The peak pressure coefficients in the corner zone were reduced by over 50% with the solid and perforated parapets placed along the perimeter of the building. Perforated parapets with a perforation ratio of 33% and having a length of 10% of the building dimension at the corners and at the ridge performed best resulting in about a 60% reduction in the peak pressure coefficients at the corners.