Should I insulate basement concrete walls from the inside or outside in a new build in McKenzie Towne?

For a new build in McKenzie Towne, exterior insulation is strongly recommended over interior insulation. Exterior basement wall insulation is the superior choice for Calgary's climate and soil conditions, and it's much easier to install properly during new construction.

Exterior insulation keeps the concrete foundation wall warm and dry, preventing condensation issues that plague interior insulation systems in Calgary's extreme climate. With exterior insulation, the concrete wall stays above the dew point year-round, eliminating the risk of moisture accumulation between the insulation and concrete. This is critical in Calgary where winter temperatures regularly hit -30°C and we experience dramatic chinook temperature swings that can cause severe condensation problems with interior systems.

McKenzie Towne sits on expansive clay soils that are notorious for foundation movement and water retention. Exterior insulation systems include integrated drainage and waterproofing that work together to keep water away from your foundation. The insulation protects the waterproof membrane from freeze-thaw damage and provides a continuous thermal barrier from footing to grade. Interior insulation can't address thermal bridging through the concrete, leaving cold spots that attract condensation.

The Alberta Building Code requires continuous insulation for basement walls in Climate Zone 7A (Calgary area). Exterior insulation easily achieves this requirement with rigid foam boards or spray foam applied to the outside face of the foundation. Common systems include 2-4 inches of rigid foam (polyiso or XPS) with protective drainage board, or closed-cell spray foam applied directly to the concrete. Typical R-values range from R-10 to R-20 depending on your energy efficiency goals.

Cost considerations for exterior vs interior: Exterior insulation costs $8-15 per square foot installed during new construction, while interior systems run $6-12 per square foot. However, exterior insulation eliminates the risk of moisture problems that can cost $15,000-40,000 to remediate later. Interior insulation also reduces your usable basement space by 3-6 inches on all exterior walls.

Professional installation is essential for exterior basement insulation. The system must integrate properly with your foundation waterproofing, weeping tile, and above-grade wall assembly. Work with your builder to specify exterior insulation in the foundation contract - it's much more expensive to add later. Ensure your contractor is familiar with Alberta Building Code requirements and local soil conditions.

Find experienced foundation contractors familiar with Calgary's challenging conditions in our verified contractor directory at Calgary Construction Network.