How much does it cost to fix chimney flashing and repoint the mortar joints in Oakville?

Chimney flashing repair and repointing in Oakville typically costs between $1,500 and $6,000 combined, depending on chimney size, height, accessibility, and the extent of mortar deterioration. Breaking that down, flashing repair or replacement runs $500 to $1,500, while chimney repointing adds $1,000 to $5,000 depending on the chimney's condition and how many courses of brick need attention.

Flashing is the metal (usually aluminum or galvanized steel) that seals the joint where the chimney meets the roof. When flashing fails, water runs down the chimney and into the roof structure, causing rot, mould, and interior damage that far exceeds the cost of the flashing repair itself. In Oakville, where Lake Ontario's humidity keeps moisture levels elevated year-round, failed chimney flashing deteriorates surrounding mortar joints faster than in drier inland areas. A qualified mason will remove the old flashing, grind out a reglet (channel) in the mortar joint, install new step flashing and counter-flashing with proper sealant, and ensure water is directed away from the chimney-roof intersection.

Repointing the mortar joints involves grinding out deteriorated mortar to a minimum depth of 20mm and packing in fresh mortar matched to the original in type, colour, and profile. For most Oakville homes built in the 1960s through 1990s, Type S mortar is appropriate — it offers high compressive strength and excellent weather resistance for exposed chimney applications. If your Oakville home is older heritage brick, the mason must use a softer lime-based mortar (Type O or Type K) to avoid damaging the brick through spalling. Using mortar that is harder than the brick is one of the most common and costly mistakes in chimney repair.

Scaffolding is a significant cost factor for chimney work. If the chimney is on a steep roof or more than one storey above grade, scaffolding adds $500 to $1,500 to the project. Some contractors use boom lifts instead, which can be more cost-effective for tall chimneys but require driveway access. In Oakville's established neighbourhoods near the lake, narrow lots and mature trees sometimes limit equipment access, so discuss staging logistics with your contractor upfront.

The Ontario Building Code requires that chimney masonry maintain its structural integrity and weather resistance. While cosmetic repointing does not typically require a building permit, any structural chimney repairs — rebuilding the crown, replacing a deteriorated chimney cap, or addressing leaning or cracked chimney structures — may require a permit from the Town of Oakville's building department. All contractors must carry WSIB coverage, which protects you from liability if a worker is injured on your property.

When getting quotes in Oakville, ask each contractor specifically about mortar type matching, grinding depth, and flashing material. A thorough contractor will also inspect and repair or replace the chimney crown (the concrete cap on top) if it is cracked, as a failed crown allows water directly into the chimney structure. Crown repair adds $500 to $2,000 but prevents the repointing work from being undermined by water entry from above. A chimney cap (the metal cover with mesh screening) should also be installed if one is not present — $200 to $800 depending on chimney size and cap material.

Get at least three quotes from experienced masonry contractors. Toronto Parging can match you with local masonry professionals through the Toronto Construction Network who handle chimney work across Oakville and the GTA.