Brick Repointing in Ottawa: What It Is, When You Need It, and What It Costs

Mortar joints in a properly constructed brick wall are not permanent. They're a sacrificial element, intentionally softer than the brick, designed to absorb movement and deteriorate before the brick itself does. In Ottawa's climate, they typically do their job for 25–30 years before they need to be replaced. Knowing when that point has been reached, and ensuring the replacement is done correctly, protects one of your home's most significant investments.

What Is Brick Repointing?

Repointing (sometimes called tuckpointing) is the process of removing deteriorated mortar from the joints between bricks and replacing it with fresh mortar. It is not a surface application, effective repointing requires removing the old mortar to a proper depth (typically 20–25mm, or about three-quarters of an inch) before the new mortar is applied. This depth is necessary for the new mortar to achieve adequate mechanical adhesion to the surrounding brick.

Repointing that doesn't remove enough mortar, or that simply applies new mortar over old deteriorated material, will fail within a few years, often sooner. The new mortar has nothing to grip.

Why Ottawa Mortar Joints Fail

The primary cause of mortar joint deterioration in Ottawa is freeze-thaw cycling. Water is drawn into the mortar joints by capillary action, particularly through any small cracks or porous areas, and when that water freezes, it expands, widening the crack and pushing mortar out of the joint. Over many cycles, joints become recessed, then crumbling, then absent.

Secondary causes include:

• Original mortar that was too hard for the brick (a common issue with older homes where Portland cement-heavy mortars were used on pre-war brick designed for softer lime mortars)
• Poor original mix design or workmanship
• Water from failed window sills, missing drip edges, or inadequate overhangs running directly into the wall
• Vegetation (vines, moss) growing on or into the wall face

Warning Signs That Repointing Is Needed

• Mortar joints that are visibly recessed compared to the brick face
• Soft mortar that crumbles when probed with a key or nail
• Cracks running along mortar joints
• White staining (efflorescence) on the brick face, indicating water movement through the wall
• Gaps visible in the joints at upper courses or near the roofline
• Any history of water entering the interior at exterior walls

The Repointing Process

A properly executed repointing job involves:

1. Joint preparation: Removing the deteriorated mortar to a minimum depth of 20–25mm using angle grinders, oscillating tools, or hand chisels. Power tools are faster but require care to avoid damaging the brick arises (edges).
2. Cleaning: Brushing out loose material and dust from the joints.
3. Pre-wetting: Dampening the substrate before applying new mortar to prevent the brick from drawing water out of the new mortar too quickly, which weakens the cure.
4. Mortar application: Packing the mortar in layers for deep joints, tooling the surface profile to match the original joint style.
5. Curing: Keeping the new mortar damp for the first 24–48 hours in hot or dry weather, shading from direct sun if necessary.

The Mortar Specification Matters

This is where many contractors get it wrong. Repointing mortar must be compatible with the existing brick, which means it must be no harder than the brick itself. Using a high Portland cement content mortar (Type S or Type M) on older, softer pre-war brick creates a mismatch: the mortar becomes harder than the brick, and when movement occurs, the brick cracks rather than the joint. This is the opposite of what mortar is supposed to do.

Older Ottawa homes, particularly those built before 1940, typically require a lime-rich mortar with relatively low Portland cement content. A Type O or Type K specification, or a custom lime-Portland blend, is usually appropriate. The goal is a mortar that is softer than the brick and vapor-permeable, allowing the wall to breathe.

How Much Does Repointing Cost in Ottawa?

Repointing cost depends on the amount of linear footage of joint, the height (scaffolding requirements), the accessibility of the wall, and the severity of deterioration. For a typical Ottawa semi-detached or detached home that needs the entire exterior repointed, costs typically range from $3, 000 to $8, 000 depending on these variables. Chimneys, which need access from the roof and often have more severe deterioration, are quoted separately.

Partial repointing, addressing the worst sections, typically the north face and areas around windows, can be significantly less. A free in-person assessment is the only reliable way to scope the work.

What to Look for in a Repointing Contractor

Ask specifically:

• How deep will you remove the old mortar?
• What mortar specification will you use, and is it compatible with my brick type?
• Do you match the original joint profile?
• Will you be doing the work, or subcontracting it?

Anyone who can't answer the mortar specification question specifically, or who says they use "regular mortar", is not the right contractor for the job.