HARGRAVE PLACE, London N7
RESOLVING RECURRING ROOF DEFECTS IN A MODERN RESIDENTIAL PROPERTY
SECTOR: Residential
SCOPE: Diagnostic Survey, Roof Repair Design, Structural Waterproofing
THE PROBLEM
Crownstone were instructed to investigate widespread water ingress at a detached residential property in Hargrave Place, affecting multiple areas across the ground and first floors. Despite the property being relatively modern, the home was suffering from persistent water ingress issues, including blistering plasterwork, visible staining, and signs of Oyster fungus (wet rot).
The cause was a failing EPDM flat roofing system and poor waterproof detailing/lapping throughout. From split membrane joints and blocked rainwater outlets to defective skylights and exposed construction membranes, water was finding multiple routes into the structure. Previous attempts at sealing defects with mastic and patchwork solutions had only exacerbated the problem.
THE PLAN
Our team carried out both non-invasive and invasive investigations across the roof areas, verandah, skylights, and internal finishes. Detailed moisture mapping, visual diagnostics, and exploratory strip-outs revealed a complex web of construction flaws, from defective parapet details to missing flashings and poor drainage installations.
The aim was clear: stop water ingress at source, re-establish a robust and breathable building envelope, and protect the structure from further deterioration. Multiple solutions were required, with each section of roof and facade needing tailored intervention.
CROWNSTONE’S SOLUTION
Our team specified a full replacement of the failing EPDM systems with new heat-welded Koster TPO single-ply roofing membrane, known for its durability and watertight integrity. Planters and decking were carefully removed and stored, allowing the roofing substrate to be stripped and rebuilt with the correct details and drainage in place.
Missing membrane and flashing details were corrected at parapet level, while oversized coping was reinstalled with new GRP and external sealants to ensure a continuous, weather-tight system. Skylight flashings and adjacent drainage gullies were reworked to prevent pooling and water contact with vulnerable masonry.
Crucially, areas showing signs of rot, including timber exposed to prolonged moisture and oyster fungus, were removed and replaced, with Boron treatment applied to surrounding timbers to prevent future decay. The internal finishes were then reinstated, with affected plasterboard and skirting cut away, dried out, and renewed.
Our comprehensive survey-to-solution approach gave this family home a second chance at a dry, defect-free future. By addressing the root causes of ingress and rebuilding with care, Crownstone helped protect both structure and peace of mind.
If you’re struggling with recurring roof leaks or damp issues in a modern property, Crownstone can help. Our expert team resolved widespread water ingress at Hargrave Place by uncovering the root causes and delivering a long-lasting, watertight roofing solution.
