Chimney Flashing Repair

The watertight transition where chimney meets roof is the leak point homeowners least suspect and contractors most often botch. Built correctly it's a two-part system: step flashing — individual L-shaped pieces woven course by course into the shingles up the sidewall — and counter-flashing set into a saw-cut reglet in the masonry and folded down over those step pieces. Built wrong, it's a bead of caulk smeared across a gap, the exact "repair" that fails inside a season and drives water into the structure. We flash chimneys as the layered, mechanical, watertight assembly they're meant to be, because all the brick waterproofing in the world means nothing while the roofline transition stays open.

We diagnose first, then repair to the right depth. A sound flashing system with a failed seal may want nothing more than the reglet reservoir re-tooled and re-sealed; a corroded or badly installed one has to come out entirely and be rebuilt — new step flashing woven into the shingles, new counter-flashing cut into a fresh reglet, lead or aluminum to suit the roof. We dress fatigued lead back down, solder copper and galvanized corners into a watertight non-caulk joint where the detail demands it, and drill weep holes where water is trapped in the masonry cavity. On a wide chimney, or one sitting in a roof dead-valley that ponds water, more flashing isn't the answer — a cricket is: a peaked metal or framed saddle built on the uphill side that diverts water and debris around the stack rather than letting it dam against the back wall. Where the wood cant or substrate beneath the cricket has rotted, we replace it before re-metaling, since new flashing over rotted backing is a guaranteed callback.

Flashing failures hide in the harder roof geometries — and that's exactly where most contractors are out of their depth. A chimney in a dead-valley, the low spot where two roof planes funnel water toward it, will pond and leak no matter how clean the step flashing looks, and the real remedy is a diverter that moves the water off before it ever reaches the stack. Water trapped inside a masonry cavity needs weep holes drilled at the flashing line to drain it, or it just sits and finds another way in. A counter-flashing reglet needs its sealant tooled into a properly backed reservoir rather than smeared across the surface, or it peels away as the building moves. On a flat commercial roof, an irregular stack penetration may call for a poured pitch pan instead of conventional flashing altogether. We diagnose the geometry, not just the metal, because the leak is so often a water-management problem the original flashing was never designed to solve.

On a flashing joint there's no partial credit — the craftsmanship is either watertight or it isn't. We document the condition, lay out honestly whether a reseal or a full replacement is warranted, and build the transition to shed water for the long term instead of buying a single season with sealant. The same flashing-and-cricket standard governs every centerpiece we're trusted with, and crickets are specified wherever chimney width or roof geometry actually demands one rather than tacked on as an upsell. Get the roofline transition right and you've sealed the leak point that defeats every other waterproofing measure — which is precisely why we treat flashing as the precision work it is, not the caulk-gun afterthought it's so often reduced to.