Repairs: roofs and rainwater goods

This can be a problem if you are adding a new, thicker deck to accommodate new insulation. You may need to adjust the DPC and cover flashing levels to re-coordinate them, unless they are already sufficiently generous.

Solution

The old cover flashing clearances may well need resetting to allow for this. It is usually futile to try to leave the original flashings in place unless there is plenty of room to spare. Ensure that contractors are not inclined to take a shortcut in this respect if you are checking the works.