How do I fix a sunken concrete sidewalk in Bathurst NB?

A sunken concrete sidewalk in Bathurst can be fixed in most cases without full replacement — the right approach depends on the cause of the sinking, the extent of settlement, and the condition of the existing concrete.

Bathurst's location on the Chaleur Bay coastline and its position in northern New Brunswick means it experiences some of NB's more severe winter conditions, with frost depths approaching 4.5-5 feet and significant spring thaw cycles. Sidewalk sinking in Bathurst is typically caused by one of three things: soil settlement beneath the slab (from organic material decomposing, inadequate compaction, or water erosion of the sub-base), frost heave that lifted the slab and then allowed it to settle unevenly as soil conditions changed, or tree root disruption that moved the soil beneath the slab.

Concrete levelling (mudjacking or poly foam injection) is the most cost-effective fix when the existing slab is structurally sound — no major cracking, spalling, or structural failure. Mudjacking pumps a slurry of cement, soil, and water beneath the slab through small drilled holes to fill voids and lift the slab back to grade. Cost in NB runs $3-$6 per square foot. Poly foam injection (also called polyurethane or foam levelling) uses expanding two-part foam injected through even smaller holes — it lifts faster, is lighter than mud (doesn't add soil pressure to soft sub-base), and cures within minutes. Cost runs $5-$10 per square foot. For a typical 3-foot by 15-foot sunken sidewalk section (45 sq ft), mudjacking costs $135-$270 and poly foam $225-$450 — both far less than the $500-$900+ cost of removal and replacement.

Levelling is not always the right answer. If the slab has significant cracking across multiple panels, the concrete surface is heavily scaled or deteriorated, or settlement is severe enough that the slab has broken into multiple pieces at different levels, replacement is the better long-term investment. Levelling a badly cracked slab addresses the height but not the structural integrity.

After levelling, address the root cause. If poor drainage allowed water to erode the sub-base, improve drainage around the area. If a tree root caused the problem, consider root barrier installation or removal of the problematic tree. Without addressing the cause, the slab will re-sink.

To get the right assessment for your Bathurst sidewalk, New Brunswick Concrete can connect you with local contractors who offer both levelling and replacement services — getting two or three opinions before committing to either approach is well worth the time.