Lead flashing is one of the most important components of a watertight roof, yet many homeowners rarely notice it until a leak appears. Flashing protects vulnerable joints around chimneys, walls, dormers and roof intersections by directing water away from gaps that tiles or slates cannot fully cover. When it fails, even the smallest gap can lead to significant water damage, rot and damp inside your home.
This guide explains what lead flashing does, the common reasons it fails, the signs to look for and how RGS Roofing Services in Essex repairs and replaces flashing to keep your roof secure and leak-free.
What Lead Flashing Is and Why Roofs Need It
Lead flashing is a durable sheet of malleable lead installed where the roof meets another surface, such as a chimney stack or adjoining wall. It is designed to create a watertight barrier that prevents rainwater from entering the roof structure.
Because roof intersections are natural weak points, flashing is essential. Without it, water would seep behind tiles or slates and reach the internal structure. Lead is widely used in the UK because it is long-lasting, flexible, weather-resistant and can be shaped to fit complex details. When installed correctly, lead flashing can protect a roof for decades.
The Most Common Causes of Lead Flashing Failure
Flashing failures occur for several reasons, often developing slowly until a leak becomes noticeable. Understanding the causes helps homeowners take action early.
Weathering Over Time
Lead expands and contracts with temperature changes. Over many years, this movement can cause cracks, splits or gaps, especially if the flashing was not installed with correct allowance for movement.
Poor Installation
Incorrect fixing, insufficient overlap, inadequate sealing or using the wrong grade of lead often lead to early failure. Poor workmanship can turn an otherwise durable material into a weak spot on the roof.
Mortar Deterioration
Flashing around chimneys and wall upstands is often held in place with mortar. Over time, mortar can crack or crumble, allowing water to creep behind the flashing.
Roof Movement
Roofs naturally shift slightly with age, weather and structural settling. Any movement can cause flashing to separate from adjoining surfaces if it is not properly supported.
Environmental Factors
High winds, storms, persistent rainfall and frost can weaken flashing. Moss and debris buildup around flashing can also trap moisture and accelerate damage.
Early Warning Signs of Flashing Problems
Spotting issues early reduces the risk of costly repairs. Common symptoms include:
Damp patches on ceilings near chimneys or walls
Staining around the loft or roof timbers
Visible gaps or lifting in the flashing
Cracked or missing mortar around the flashing
Drips or wet areas inside the loft during rain
Loose or rattling flashing during windy weather
If your home shows any of these signs, the flashing may already be compromised and should be inspected by a professional.
How Roof Flashing Leaks Damage Your Home
Ignoring flashing problems can lead to:
Timber rot inside the roof
Damage to insulation
Ceiling staining and plaster damage
Mould growth and damp
Structural deterioration in the long term
Because flashing is often located around chimneys and walls, leaks typically spread vertically and horizontally, making damage harder to locate without specialist expertise.
Lead Flashing Repair Methods
Several repair options are available depending on the severity of the damage.
Localised Repairs
If only a small section is damaged, lead patching or re-dressing the flashing may be enough. Mortar joints can also be repointed to secure the flashing and restore watertightness.
Step Flashing Replacement
When step flashing along a wall or chimney has deteriorated, replacing the affected section with new lead provides a long-term solution.
Full Flashing Replacement
If the flashing has reached the end of its lifespan or was installed incorrectly, full replacement is the best approach. This involves removing old materials, preparing the surface and fitting new lead with correct overlaps, fixings and movement joints.
Modern Alternatives
In cases where weight or cost is a concern, non-lead alternatives can be installed. However, lead remains the most durable and traditional choice for UK roofs.
Preventing Future Flashing Problems
Regular inspections help identify issues before they become leaks. Homeowners should:
Check flashing annually, especially after storms
Look for loose mortar, cracks or lifting
Keep moss and debris from accumulating around chimneys
Ensure roof repairs include flashing assessments
Professional maintenance extends the life of flashing and reduces the risk of urgent repairs.
How RGS Roofing Services Repairs and Installs Lead Flashing
RGS Roofing Services has extensive experience working with both traditional and modern flashing systems across Hornchurch and Essex. Our team:
Conducts thorough inspections to identify the source of leaks
Reinstalls flashing using correct techniques and high-quality lead
Ensures all movement joints are properly accounted for
Repairs damaged mortar joints and surrounding roof materials
Provides clear recommendations for long-term protection
With precise installation and careful detailing, flashing becomes a strong, reliable part of your roofing system.
Quick Takeaways
Lead flashing protects your home at vulnerable roof joints
Most flashing failures come from age, weather or poor installation
Early signs include damp, staining and visible lifting
Timely repairs prevent internal damage and mould
RGS Roofing Services provides expert flashing repair and replacement
Contact
Lead flashing is one of the strongest defences against roof leaks, but only when it is installed and maintained properly. Understanding why flashing fails and recognising the early signs helps homeowners prevent costly repairs and long-term structural damage. Whether your flashing has weathered over time or has been poorly fitted in the past, addressing the issue promptly ensures your home stays dry and protected.
For reliable flashing repairs or inspections in Hornchurch and across Essex, contact RGS Roofing Services on 01708 702 216 or email rgsroofingservices@gmail.com today.
FAQs
How long does lead flashing last?
When installed correctly, lead flashing can last several decades.
What is the main cause of flashing leaks?
Weathering and poor installation are the most common causes.
Can flashing be repaired, or does it need replacing?
Both options are possible depending on the severity of the damage.
Is lead still the best material for flashing?
Yes, lead remains the most durable and flexible option for UK homes.
Should flashing be checked regularly?
Annual inspections help prevent leaks and detect early damage.
