Parging is the thin coat of cement-based mortar applied to the exterior surface of your foundation walls. While it may look like a purely cosmetic finish, parging serves critical protective functions — it shields your concrete or block foundation from water penetration, freeze-thaw damage, and deterioration. In Ottawa's extreme climate, where foundations endure temperatures from -30°C to +35°C and 50+ freeze-thaw cycles annually, well-applied parging is your foundation's first line of defense. Crumbling, cracked, or missing parging is one of the most common exterior maintenance issues on Otta...
1. What Is Parging & Why It Matters 2. Parging Costs in Ottawa (2026) 3. Common Parging Problems in Ottawa 4. The Parging Application Process 5. Choosing a Parging Contractor in Ottawa 6. Parging Materials & Mix Options 7. Parging Maintenance Tips 8. When to Repair vs. Replace Parging
Parging is a 3/8 to 1/2 inch thick layer of mortar applied to foundation walls, typically from the footing to just above grade level. While it improves the appearance of rough concrete or block foundations, its primary purpose is protective: Moisture Barrier: Parging creates a smooth, continuous surface that sheds water rather than absorbing it. Bare concrete and especially concrete block foundations are porous — they absorb water that then freezes inside, causing spalling (surface flaking) and...
Parging costs in Ottawa are typically quoted per linear foot or per project: New Parging Application: Per linear foot (average 2-foot height): $15–$30 Per square foot: $8–$15 Typical Ottawa home (full perimeter, 150 linear feet): $2,250–$4,500 Front-only or visible sides: $800–$2,000 Parging Repair: Small patch repair (under 20 sq ft): $300–$600 Moderate repair (20–50 sq ft): $600–$1,500 Extensive repair (50+ sq ft): $1,500–$3,500 Full Parging Removal & Replacement: Per linear foot: $20–$40 T...
Ottawa's climate creates specific parging challenges: Cracking: Hairline cracks are normal as parging cures. Wider cracks (over 1/8 inch) indicate movement, improper mix, or freeze-thaw damage. Cracks allow water entry, accelerating further deterioration. Spalling/Flaking: The parging surface breaks away in layers. This is the most common failure mode in Ottawa, caused by water penetrating the parging and freezing. Once spalling starts, it accelerates rapidly because the exposed area absorbs m...
Proper parging application follows these steps: Surface Preparation: The foundation surface must be clean, free of loose material, and dampened (not wet). Old deteriorated parging must be removed completely — never apply new parging over failing old parging. Cracks in the foundation should be repaired before parging. Bonding Agent: A liquid bonding agent (or cement slurry) is applied to improve adhesion between the foundation and new parging. This step is critical for adhesion to smooth poured...
Parging is a masonry trade that requires specific skills: Masonry Experience: Choose a contractor with masonry experience — parging, brickwork, and concrete repair are related skills. General contractors or painters who 'also do parging' often produce inferior results. Ottawa Climate Knowledge: Your contractor should use Ottawa-appropriate mixes that withstand freeze-thaw conditions. Standard parging mixes used in milder climates may fail within 2–3 Ottawa winters. Ask what additives they use ...
New parging in Ottawa costs $15–$30 per linear foot or $8–$15 per square foot. A typical Ottawa home (full perimeter) costs $2,250–$4,500. Repairs cost $300–$1,500 for small patches. Full strip and replacement costs $3,000–$6,000. Parging is one of the most affordable foundation protection investments.
Quality parging in Ottawa lasts 15–25 years when properly applied with appropriate materials and maintained regularly. Ottawa's freeze-thaw cycles are the primary aging factor. Polymer-modified and fibre-reinforced parging mixes last longer than standard mortar. Snowline areas deteriorate fastest.
Small patch repairs are feasible for DIY homeowners. Full parging application requires skill, proper tools, and technique for a good result — uneven thickness, improper mix, or poor surface prep leads to premature failure. For visible areas (front of house), professional application ($2,000–$4,500) provides better results and longevity.
May through September is ideal — temperatures should be 5–30°C with no frost expected for 48 hours. The mortar needs warm, humid conditions to cure properly. Avoid hot direct sun during application (causes too-rapid drying). Never apply parging when temperatures are below 5°C.
Ottawa parging fails primarily from freeze-thaw damage (water penetrates, freezes, and pushes parging off the wall), poor surface preparation, incorrect mix, application in cold weather, too-thin application, and mechanical damage (snowplows, lawn equipment). The snowline area (12–18" above grade) fails most frequently.