The edging around a pitched roof is called a verge. The verge is where your roof tiles meets the gable end of your home. Mortar is applied to the verge to hold any roof tiles in place and will act as a seal to stop the rain from getting underneath them. Unfortunately, over time, this can crumble and break, leaving your roof open to the bad elements. This is when you are going to need the verge repointing.
This is when you will need to contact an Essex Roofing company like Essex Roofing Services to carry out this service.