How much rebar is needed in a residential foundation in NB?

A typical NB residential foundation uses both horizontal and vertical rebar — #15M (metric 15) bars are standard for foundation walls, typically placed vertically at 16-24 inch centres and horizontally at 24-48 inch centres, plus two continuous #15M bars in every footing. This is a general guideline; the exact reinforcement schedule for your foundation should be specified by your designer or engineer and confirmed to your local building authority.

Why rebar matters in NB foundations: Concrete is strong in compression but weak in tension. Soil pressure, frost heave, and hydrostatic water pressure all exert forces that try to bend and crack foundation walls. Rebar placed in the tension zone of the wall resists these forces and, critically, holds the wall together even if cracking occurs — preventing progressive failure.

Footing reinforcement: Two continuous #15M (or #10M for lightly loaded footings) bars running the length of each footing strip are standard in NB residential construction. The bars should be positioned in the bottom third of the footing and maintained at least 75 mm (3 inches) from the outside edge. Corner footings require overlap and tie bars extending into both legs.

Foundation wall reinforcement: Vertical bars are the primary structural reinforcement resisting lateral soil pressure. #15M bars at 16-inch centres provide good performance for typical NB residential walls up to 8 feet of backfill. For walls with greater backfill height or on soft soil sites, tighter spacing or larger bar sizes may be required. Horizontal bars tie the vertical bars together and resist temperature and shrinkage cracking — typically #10M or #15M at 24-48 inch centres.

Key installation details for NB conditions: Rebar must be positioned with proper concrete cover — 50-75 mm (2-3 inches) from the outside face of the wall for below-grade concrete exposed to soil and potential moisture. This cover protects the steel from corrosion. Rebar must be held in position with wire ties and spacers (chairs) — rebar that shifts during the pour is rebar that does not provide the design protection.

Estimating rebar quantity: A typical NB home basement with 120 linear feet of foundation wall (30x30 ft footprint) and 8-foot-tall walls will require approximately 600-900 linear feet of vertical #15M bars plus 400-600 linear feet of horizontal bars, plus footing bars. At $2.50-$4.00 per linear foot for #15M, the rebar material cost alone for a full foundation runs $3,000-$6,000. Labour for placing and tying rebar is typically included in the foundation contractor's forming and placement price.

Always have your foundation reinforcement inspected before the pour — your building permit requires an inspection at this stage for good reason.