North Walsham Roofers carries out lead flashing and weathering work for homes in Mundesley, cutting, dressing, and fixing lead to the correct Code specification on chimneys, dormers, skylights, and valley junctions.
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Lead flashing is used at every point where your roof covering meets a wall, upstand, or change of plane. That means chimney stacks, dormer cheeks and heads, the kerbs around roof windows, and the valleys between roof slopes. At each of these junctions, correctly dressed lead forms a watertight seal that sheds water reliably without relying on mastic or sealant alone.
Lead is specified by Code number, which represents the thickness of the sheet. The right Code for any given location depends on the size of the area being covered and the stresses the lead will face. Code 4 or 5 is standard for most chimney and dormer flashings. Code 5 and 6 is used for valleys and larger parapet gutters. Using a lighter Code than is specified for a location is one of the main reasons lead fails before it should.
Correctly installed lead requires very little active maintenance - that is one of its main advantages as a roofing material. But there are simple checks and basic tasks that extend its life and, more importantly, help you catch small problems before they become expensive ones. This is worth paying attention to because the consequences of a failed flashing are rarely just the cost of the lead itself; it is the water damage to plasterwork, timbers, and ceilings underneath that runs up the real bill.
Good lead work on a chimney, for example, typically lasts several decades when it has been correctly installed to the right Code, properly chased and wedged into the brickwork, and dressed in bays of the right length. But even sound lead can be undermined by things that have nothing to do with the lead itself - mortar joint erosion, vegetation growth, debris build-up in valleys, and physical damage from falling branches or aerial work.
You do not need to get onto your roof to carry out a useful check. From the ground with a pair of binoculars, look at the following once or twice a year, ideally in autumn before heavy rain sets in and again in spring:
One of the most useful things a homeowner can do - without going near the lead itself - is to keep gutters clear. Blocked gutters cause water to back up under the eaves and can also increase the volume of water sitting in a valley junction during heavy rain. Clearing gutters in autumn, and again after any significant storm, reduces the load on valley lead and the adjacent soakers.
Moss and lichen on the roof covering near a lead valley should also be watched. As moss growth loosens old tiles or slates at the valley edge, debris washes down and settles in the valley channel. A heavily blocked valley is not always visible from the ground, so it is worth having this checked as part of any roof inspection.
A small amount of patina on lead is normal and does not indicate a problem. Lead naturally oxidises to a grey-white colour and this surface layer is actually protective. Moss growing on top of lead, however, holds moisture and can cause the lead to pit over time. If you notice heavy moss growth on a lead valley or flat section, it is worth having it cleared as part of a general roof maintenance visit.
Do not use pressure washing on lead. High-pressure water can force debris into lap joints and can damage the surface of older lead. A soft brush and gentle manual clearing is the right approach.
Some lead failures show internally before they are visible on the roof. Check the following if you have any reason to think a flashing may have been compromised:
If you spot any of these, it is worth having the roof inspected promptly rather than waiting to see if it worsens. Water ingress at a flashing point rarely stops on its own, and timber that stays damp long enough will begin to deteriorate.
After any significant weather event, it is worth a ground-level check of any lead that was previously repaired or that you know to be older. Wind can lift a section of lead that was only lightly wedged or whose pointing has become loose. If you notice lead standing proud of the brickwork after wind, have it inspected before the next significant rainfall - an open chase can allow a surprising amount of water in.
Not everything warrants urgent attention, but some signs do. If you can see that lead has physically pulled away from a junction and there is an open gap, that needs addressing before rain. If internal staining is fresh or growing, that indicates active water ingress. And if you have had a repair carried out with flashing tape or mastic, it is worth knowing that these materials typically last only a few years before they need replacing or proper lead work is done in their place.
Whatever your location, if you want a roof survey to check the condition of your lead work, or if you have noticed one of the warning signs above, arrange an inspection with a qualified roofer.
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Call any time. Calls are answered day and night and passed straight to our roofers.
