Water under trapezoidal roof sheets: a leak or condensation?
Water can appear on the underside of trapezoidal sheets after a dry night. Before arranging to replace the sheets, note the weather, the time and the pattern of wet patches. Does the water appear around one roof penetration or over a broad area of cold metal? The first pattern can suggest a leak and the second condensation. Neither observation alone settles the cause. A roof section drawing and details of heating and ventilation will help a roofer trace the water and establish whether the repair concerns the covering or the layers beneath it.









