Nordic Damp Proofing recently completed extensive parapet wall repairs and lead flashing remedial works at a property in BS3, Bristol after the homeowner reported persistent water ingress affecting the property.
Following our inspection, multiple defects were identified along both the client’s and neighbouring parapet walls. Deteriorating render, failed lead detailing and weathered mortar joints had all contributed to moisture penetrating the roof structure over time.
To provide a long-term solution, the defective parapet walls were carefully stripped back, repaired and re-rendered while the lead flashings were reinstated to create a continuous weatherproof barrier.
Assessment Findings
During our survey, we identified several defects contributing to the water ingress.
Over many years, exposure to the elements had caused sections of the parapet render to crack and separate from the masonry, allowing rainwater to penetrate behind the wall.
The existing lead flashing also showed signs of deterioration in several locations, with previous repairs and movement leaving vulnerable areas where water could track beneath the leadwork.
Our inspection identified:
- Cracked and defective parapet render.
- Failed mortar joints around coping stones.
- Defective lead flashing details.
- Areas of displaced lead requiring redressing.
- Evidence of long-term weathering to both parapet walls.
- Localised deterioration around junctions between the roof covering and parapet walls.
As the defects extended across both adjoining walls, repairs were completed to both elevations to ensure a continuous weatherproof finish.
Removing Defective Render
The first stage of the project involved carefully removing all loose and defective render from both parapet walls.
By stripping the walls back to a sound substrate, we were able to expose any hidden defects before commencing repairs.
Any loose material, failed mortar and deteriorated render were removed to provide a solid foundation for the new render system.
Repairing the Parapet Walls
Once preparation had been completed, the masonry was repaired before applying a new breathable render system incorporating a waterproof additive.
Cracks, voids and weathered areas were rebuilt to restore the integrity of the parapet walls while maintaining breathability, allowing trapped moisture within the structure to escape naturally.
The new render provides both improved weather resistance and a clean, uniform appearance.
Lead Flashing Repairs & Reinstatement
With the masonry repairs completed, attention turned to the roof junctions.
All lead flashing details were inspected before being carefully redressed and reinstated where movement had occurred.
External-grade sealant was applied where required to ensure the flashing remained fully weatherproof while maintaining flexibility to accommodate normal thermal movement.
Areas where the render met the lead were reinstated to create a continuous weatherproof finish without compromising the flashing detail.
These repairs help prevent rainwater from tracking behind the parapet walls and into the roof structure.
Coping Stone & Roof Junction Repairs
The parapet coping stones were also inspected as part of the works.
Any defective joints were resealed to minimise water penetration through the top of the wall while ensuring the surrounding render and lead detailing formed a complete weatherproof system.
By addressing every junction rather than isolated defects, the risk of future leaks has been significantly reduced.
The Importance of Repairing Parapet Walls
Parapet walls are one of the most common sources of water ingress on older properties.
Over time, movement, frost damage and exposure to the weather can cause render to crack and lead flashings to deteriorate. Once water begins entering behind the parapet, it can travel significant distances before appearing internally, making leaks difficult to diagnose.
Repairing both the masonry and leadwork together provides a far more reliable long-term solution than simply sealing isolated cracks.
The Finished Result
The completed project has restored the weather protection of both parapet walls while improving the integrity of the roof junctions.
The homeowner now benefits from:
- Fully repaired parapet walls.
- New breathable waterproof render.
- Reinstated lead flashing.
- Sealed coping stone joints.
- Improved protection against penetrating damp.
- A professional finish designed for long-term performance.
Penetrating Damp Specialists in Bristol
Nordic Damp Proofing provides specialist investigations and remedial repairs for penetrating damp, leaking parapet walls and defective roof details throughout Bristol and the surrounding areas.
Rather than treating the symptoms, we identify the true source of water ingress before recommending the most appropriate long-term repair.
