Lead sheets for covering roofs - have parallel double folds to allow length to be adjusted

摘要

A roof is covered and sealed with lead sheets. Each sheet has parallel folds (7, 7') with the material being folded double with four successive double folds. The distance between successive folds (7, 7') is significantly greater than the overall width of the folded sheet. The overall thickness of the folded sheet in the region of the fold is determined by the number of layers of material in the region of the fold. - These folds enable the effective length of each sheet to be adjusted to ensure that the roof is properly sealed, especially around the frames of roof windows.