How do I prevent frost heaving in a paver walkway in New Brunswick?

Preventing frost heaving in a New Brunswick paver walkway requires a properly engineered granular base, good drainage, and careful material selection — the three factors that determine whether your walkway stays level or buckles with every spring thaw. NB's frost depth of 1.2 to 1.5 metres means the ground moves significantly every winter, and without these defences, heaving is inevitable.

The base depth is your primary defence. Excavate the walkway path to a depth of 12 to 14 inches below the finished paver surface. Fill with compacted granular A gravel (3/4-inch crushed stone with fines) in 2-inch lifts, compacting each lift with a plate compactor to at least 95% density. This granular base allows water to drain down and away rather than sitting beneath your pavers and freezing. The principle is simple — frost heave occurs when water in soil freezes and expands. Remove the water and you remove the heaving.

Drainage is the second critical factor. Ensure the walkway has a cross-slope of at least 2% (approximately 1/4 inch per foot) so water runs off the surface rather than seeping between joints and saturating the base. In areas where the walkway runs alongside a house or retaining wall, install a 4-inch perforated drainage pipe wrapped in filter fabric along the low side, directing water to a suitable outlet. NB receives 1,100–1,200mm of annual precipitation plus significant spring snowmelt — any walkway that traps water beneath it will heave.

Geotextile fabric between the native soil and the gravel base is essential in Fredericton's clay-heavy river valley soils and recommended everywhere in NB. Without it, fine clay particles migrate upward into the gravel base over time, clogging drainage channels and creating the water-retaining conditions that cause frost heave. The fabric costs only $0.50–1.00 per square foot and can extend your walkway's lifespan by years.

Edge restraints prevent lateral movement that accelerates heaving damage. Use heavy-duty polyethylene or aluminum edge restraints spiked into the compacted base with 10-inch galvanized spikes. Without proper edging, NB's freeze-thaw cycles will gradually push pavers outward from the edges, opening joints and allowing water infiltration that worsens heaving.

Polymeric sand in the joints is a must for NB walkways. It binds pavers together, preventing individual units from lifting independently during freeze-thaw cycles. It also blocks water from seeping between joints into the base layer. Apply polymeric sand on a dry day when temperatures are above 0C and no rain is forecast for 24 hours.

Even with perfect installation, minor settling may occur after the first NB winter. Budget for a spring tune-up — lifting any shifted pavers, re-levelling the bedding sand, and re-applying polymeric sand. This 1–2 hour maintenance task in April prevents small issues from becoming costly repairs. Professional walkway installation in NB costs $20 to $35 per square foot, and the investment in a proper base saves thousands in future repairs.

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