What is the timeline to dig out a crawlspace and convert it to a full basement in a 1950s bungalow in Mount Royal?

Converting a crawlspace to a full basement in a 1950s Mount Royal bungalow is a major structural project that typically takes 3-6 months, depending on soil conditions, structural complexity, and permit approvals.

This type of underpinning project is extremely complex and requires careful engineering assessment before any work begins. Mount Royal's established character and proximity to the Elbow River means you're likely dealing with variable soil conditions and potential groundwater issues that can significantly impact both timeline and cost.

The Engineering and Permit Phase typically takes 6-12 weeks and is critical for success. A structural engineer must assess your existing foundation, design the underpinning system, and determine excavation methodology. In Calgary's expansive clay soils, this often involves helical piles or concrete piers to support the house during excavation. The City of Calgary requires detailed structural drawings and a development permit for this scope of work. Given Mount Royal's heritage character area designation, there may be additional design review requirements that can extend permit timelines.

The Construction Phase breaks down into several stages. Initial preparation and utility disconnection takes 1-2 weeks. The actual underpinning and excavation process is the most time-sensitive phase, typically requiring 4-8 weeks of continuous work. Contractors must excavate in small sections (usually 3-4 foot segments) while maintaining structural support. Calgary's frost depth of 4+ feet means extensive excavation, and Mount Royal's mature trees and tight lot lines can complicate equipment access. New foundation walls, waterproofing, and weeping tile installation add another 3-4 weeks.

Calgary-Specific Challenges significantly impact timelines. The city's expansive clay soils can shift unexpectedly during excavation, requiring engineering modifications. Mount Royal's established neighborhood means limited equipment access - larger excavators may not fit between houses, requiring smaller equipment and longer timelines. Utility conflicts are common in older neighborhoods, and relocating gas, electrical, or water services can add weeks to the project. Weather restrictions limit excavation work to May through October in Calgary's climate.

Professional Requirements are non-negotiable for this scope of work. You'll need a structural engineer, licensed general contractor experienced in underpinning, and multiple Safety Codes Council of Alberta permits (building, electrical, plumbing, gas). All contractors must carry WCB Alberta coverage given the high-risk nature of underpinning work. Expect costs in the $80,000-$200,000 range depending on square footage, soil conditions, and access challenges.

Next Steps should begin with a structural engineering consultation to assess feasibility. Many 1950s foundations in Mount Royal may not be suitable candidates for underpinning due to shallow footings or deteriorated concrete. The engineer will determine if your foundation can support the underpinning process and design the appropriate support system. Only proceed with contractors who have extensive underpinning experience and can provide references from similar projects in Calgary's established neighborhoods.