April 15, 2026

Flat Roof Leak Repair on a Classic Stone Home in Winnetka: A Silicone Coating Project

A flat balcony roof on a Winnetka stone home was leaking through to the living space below. Cracked membrane, failed flashing, no drainage. We restored full waterproofing with Gaco Silicone Roof Coating — no tear-off.

The problem: a leaking balcony roof on a Winnetka stone home

The homeowner called about ceiling stains from a flat balcony roof sitting above a living space. Water was getting through — plaster was peeling, the ceiling near the smoke detector had stained, and a bucket was in place to catch drips. The roof above hadn't been addressed in a long time, and every rain was making the interior damage worse.

Ceiling water stain near smoke detector, Winnetka stone home interior — Interior: water staining on the ceiling below the leaking balcony roof, next to the smoke detector.

Interior room with leaking ceiling, bucket on floor, Winnetka IL — Interior: paint and plaster failing on the ceiling above the window — bucket in place to catch drips.

Plaster ceiling peeling and falling from water damage, Winnetka IL — Interior: plaster ceiling actively failing — large sections peeling and falling from sustained water intrusion.

Ceiling cracks with water staining next to smoke detector, Winnetka IL — Interior: hairline cracks and rust-colored water staining spreading across the ceiling near the smoke detector.

What we found on inspection

Three failures, all contributing. The membrane had open cracks and bubbled, aged sections throughout — no longer watertight. Flashing had pulled away at the wall terminations, leaving open seams and exposed screw holes where loose conduit straps had failed. Debris had piled up at the wall seam, trapping moisture against the stone and flashing. And drainage was broken: four upper-roof downspouts had no elbows, pouring water straight down the wall onto the balcony. We documented everything and wrote a clear scope before any work started.

Standing water on Winnetka balcony flat roof before repair — Before: standing water pooling across the balcony roof — drainage was not functional.

Downspout with no elbow and loose electrical conduit on Winnetka stone home before repair — Before: downspout with no bottom elbow directing water directly against the wall, and electrical conduit pulling away from the stone facade.

Narrow roof section on Winnetka stone home before silicone coating repair — Before: the narrow roof section adjacent to the balcony showing deteriorated surface and failed flashing at the wall.

Major debris pileup at stone wall and flashing seam, Winnetka flat roof — Before: major debris pileup at the wall intersection — trapped moisture against the stone and flashing, accelerating the failure.

Open crack across flat roof membrane surface, Winnetka stone home — Before: open crack running across the roof membrane surface — a direct path for water into the assembly.

Aged flat roof with cracks and bubbles in the membrane, Winnetka IL — Before: aged roof with cracks and bubbled sections throughout — the membrane was no longer watertight.

Close-up of open screw hole in flashing at wall seam, Winnetka IL — Before: open screw hole in the flashing at the wall seam — a direct route for water into the assembly.

Peeling flashing pulled away from the stone wall with exposed hole, Winnetka IL — Before: flashing peeled away from the stone wall with a clean hole through the metal — nothing left to seal the transition.

The repair: Gaco Silicone Roof Coating, flashing, and drainage

Cleared all debris. Replaced failing flashing and re-caulked every seam. Applied two full coats of Gaco Silicone Roof Coating in black — a seamless waterproof membrane that bonds directly to a sound substrate, no tear-off required. Replaced all four upper-roof downspouts with proper elbow terminations so water drains away from the house. Re-strapped the electrical conduit with longer straps to close the open flashing holes and pull the conduit flat to the wall.

Gaco Silicone Roof Coating being applied to Winnetka flat roof — During: applying Gaco Silicone Roof Coating — two full coats over the cleaned and re-caulked surface.

Freshly coated narrow roof section with silicone membrane, Winnetka IL — During: the narrow roof section after coating — seamless silicone membrane over the former cracks and open seams.

Close view of freshly applied Gaco silicone coating on balcony roof, Winnetka IL — During: close view of the balcony roof with fresh Gaco Silicone Coating — wet finish before cure.

Stone home exterior with newly coated balcony roof and iron railing, Winnetka IL — During: wider view of the coated balcony and stone facade — iron railing and conduit back in place.

Why silicone coating instead of a full replacement

Coating is the right call when the deck is sound and the problem is at the surface. If insulation or decking is waterlogged, coating over it traps the damage. Here, the deck was intact — cracking, open seams, and failed flashing were the leak path, not rotted structure. Gaco fixed the actual problem at a fraction of the cost and disruption of a tear-off, and kept the balcony usable throughout.

Completed job

Balcony and narrow section finished clean — uniform black surface, sealed seams, flashing tight to the wall. Downspout elbows directing water away from the structure. Conduit secured flat. We confirmed full cure before handing the balcony back. Scope included the original coating plus the drainage and conduit work found during the job.

Completed Gaco Silicone Roof Coating on Winnetka balcony roof — After: completed Gaco Silicone Roof Coating on the Winnetka balcony roof system.

Completed flat roof with silicone coating, Winnetka IL — After: finished roof surface — seamless silicone coating across the full balcony.

Completed Winnetka stone home roof repair with new downspouts — After: completed roof with new downspout elbows directing water away from the stone facade.

Winnetka flat roof completed with silicone coating and secured conduit — After: finished exterior — secured conduit and clean roof coating edges.

If you have a flat roof section, don't wait for ceiling stains

By the time a ceiling stain appears, water has usually been moving through the assembly for a while — and the scope only grows from there. If you have a balcony, garage, or any flat section on a North Shore home, get it looked at before the damage reaches the interior. Chat with us on the site, fill out the contact form, or call (708) 847-5418 to schedule a free inspection. Leaders Roofing serves Winnetka, Kenilworth, Glencoe, Highland Park, Lake Forest, and the surrounding communities.