The Repair That Costs a Few Days Now or a Few Months Later
Picture two neighbours on the same Kitchener street with identical brick homes built in the same decade. One calls a mason when they notice the mortar joints starting to recede. The other puts it off through two more Ontario winters. The first homeowner spends a few days on a repointing job. The second homeowner spends the following spring dealing with spalled brick faces, damaged wall ties, and water infiltration that has reached the interior finishes. Same starting condition. Very different outcomes based entirely on timing.
Mortar joints are the unsung workhorses of a brick home's exterior. They are softer than the brick by design, intended to absorb the stresses of thermal expansion and contraction, seasonal movement, and weather cycling so that those stresses do not crack the brick itself. This means mortar has a finite service life and will eventually need to be replaced regardless of how good the original installation was. For homeowners in Stratford, Kitchener, Hamilton, and across Southwestern Ontario, when that replacement happens matters as much as how it is done.
"The repair scope I see most often isn't caused by bad brick or bad original installation. It's caused by joints that needed repointing three winters ago and didn't get it. By the time I'm called, the mortar job has become a brick job." - Matthew Howe, Stone Haven
The Mortar Joint Deterioration Cycle in Ontario
Fresh mortar in a well-executed joint is dense, fully adhered to the brick on both sides, and presents a continuous sealed surface against moisture. Ontario's freeze-thaw climate initiates a slow breakdown process that follows a predictable sequence:
- Small surface cracks develop in the mortar and begin capturing water from rain and snowmelt
- Captured water freezes and slightly widens the crack through each freeze-thaw cycle
- Through multiple seasons, the crack grows and the mortar loses its adhesion to the brick face
- The joint becomes hollow, recessed, or opens into a visible gap that allows direct water entry into the wall assembly
- Water entering the wall reaches the brick, wall ties, and potentially interior finishes before any surface sign is obvious
The rate of deterioration depends on several factors. South and west-facing walls deteriorate faster due to greater sun exposure and weather cycling. A concave or flush joint that sheds water is more durable than a raked joint that captures it. On many older Ontario homes where joints have been raked more deeply than appropriate in previous repairs, the deterioration cycle accelerates considerably.
Why Correct Mortar Specification Is the Critical Variable
The most important decision in any mortar joint repair is the mortar specification. Using the right mortar for the brick type extends the service life of the repair to decades. Using the wrong mortar can produce visible failure within a single Ontario winter.
The fundamental rule: replacement mortar must be no harder than the original mortar, and for brick laid before approximately 1950, significantly softer.
What happens when this rule is not followed:
- Hard mortar on soft brick: The wall system can no longer flex as a unit. Stresses the mortar used to absorb transfer to the brick face instead.
- Brick face spalling: The brick begins to lose its fired outer layer, exposing the softer interior to direct weather exposure
- Accelerated deterioration: Spalling brick deteriorates faster than intact brick, compounding the damage from the original mortar error
- Increased repair scope: What would have been a repointing job becomes a partial brick replacement project
The standard Type S Portland cement mortar used in modern construction is appropriate for newer, harder brick in foundations and below-grade applications. It is not appropriate for older Ontario homes with softer, more porous brick. Tuckpointing vs Repointing Ontario covers the mortar specification question in more detail. How Much Does Masonry Cost in Ontario provides context on what properly specified repointing costs relative to deferring the repair.
The Repointing Process at Stone Haven
Stone Haven's repointing process begins with Matthew's assessment of the existing mortar to determine its type and hardness, which informs the specification of the replacement mortar. The full process:
- Assessment: Existing mortar is evaluated for type, hardness, and depth of deterioration to define the correct replacement specification
- Removal: Old mortar is removed to the appropriate depth using an angle grinder or cold chisel and hammer for smaller areas, taking care not to damage the brick arrises at the joint edges
- Cleaning: The joint is thoroughly cleaned of all dust and debris, and brick faces are protected during the work
- Mixing: Fresh mortar is mixed to the specified blend matched to the original brick type and age
- Application: Mortar is pressed firmly into the joint in lifts to ensure full adhesion and eliminate voids
- Tooling: The joint is finished to the appropriate profile that sheds water rather than capturing it
Stone Haven Masonry Repair Ontario Guide covers the full repair process and what homeowners can expect at each stage from assessment through project completion.
Frequently Asked Questions
Q: How does mortar joint repair work and why is it important to address it promptly in Ontario?
Mortar joint repair involves removing deteriorated mortar to an appropriate depth, cleaning the joint, and filling with correctly specified fresh mortar that matches the original brick's hardness requirements. Addressing deteriorated joints promptly in Ontario prevents water infiltration through open joints from damaging the brick, wall ties, and interior finishes, transforming a maintenance repair into a significantly more costly restoration. Stone Haven specifies mortar based on original brick type and age.
Q: Can I do mortar joint repairs on my Ontario home myself?
Small areas of mortar repair can be attempted by homeowners with patience and careful attention to mortar specification. The critical risk is using a modern hard mortar on older soft brick, which can cause brick face spalling within one or two seasons. For homes more than 30 to 40 years old, or for any larger area of joint deterioration, professional assessment and repair is recommended. Stone Haven provides free assessments for homeowners who are unsure of the scope.
Q: How do I know if my brick home needs repointing or more extensive work?
If your mortar joints are recessed, crumbling, or open but the brick faces themselves are intact and the wall is plumb and stable, repointing is likely the appropriate scope. If bricks are spalling, loose, bulging, or if there are signs of structural movement in the wall, a more thorough assessment is needed before any repair approach is defined. Stone Haven provides free documented assessments for Ontario homeowners uncertain about the scope of their masonry situation.
Mortar joints showing deterioration on your Ontario brick home? Get a mortar repair quote from Stone Haven for an honest assessment of your joints and what addressing them now will cost compared to deferring. Explore all masonry repair services at Stone Haven today.
