Use a walkthrough to direct the inspection, not to replace it.
Equal opening area. A very different short side.
0.36 m² of clear opening
Shortest side: 600 mm
0.36 m² of clear opening
Shortest side: 300 mm
Both have the same area. The narrow opening has a short side below the 380 mm minimum in the City's existing-suite guidance. Shapes are shown at different scales.
First establish which requirements apply
An older existing suite, a new basement conversion and a backyard building can follow different requirements. That is why one universal ceiling height, drywall thickness or ventilation recipe can be misleading. Start with the project history, City guidance and approved plans for the address.
Ask the designer or inspector to identify the applicable route and any limits to their assessment. If a seller says the work passed, ask which inspection, when it occurred and whether anything changed afterwards. A general home inspection can identify concerns but does not substitute for municipal approvals or a detailed design review.
Follow the escape route before admiring the kitchen
Look at how someone leaves each bedroom and how they get from the suite to outdoors. Notice windows that will not open, deep wells, obstructions, awkward stairs and storage in the way. Mention these to the inspector. In Calgary winters, snow and ice management also deserve a practical plan.
Window compliance depends on the usable opening and arrangement, not just the size of the glass. Enlarging a foundation opening can involve structural work, excavation and drainage. Before treating it as a small repair, obtain a qualified assessment and an itemized quote.
The window frame is not the escape opening
Why two windows with the same area can give different answers
For the existing-suite route, Calgary's published guidance specifies at least 0.35 m² of unobstructed opening and no opening dimension below 380 mm. A 600 × 600 mm opening has 0.36 m² of area. A 1,200 × 300 mm opening also has 0.36 m², but its short side is below 380 mm. This example explains the measurement; it does not approve either installed window.
The same City guide distinguishes existing and newly installed window wells, and the sash must not defeat the escape space. Have the applicable route, actual opening, well and operation assessed together. If enlargement is proposed, the quote should address foundation work, excavation, drainage and making good the finishes—not just the new window.
Ask what is behind the finished surfaces
Separation between homes is a system: floors, walls, doors and penetrations all matter. A freshly painted ceiling does not reveal how an assembly was built or whether later plumbing and duct changes affected it. Ask for drawings, permit information and construction photographs where available.
Do not prescribe a drywall product based on an online article. The appropriate assembly and details need to be confirmed for the project. Ask the professional what can be checked visually and what would need access, documents or further investigation. Keep any unverified concealed work visible in your decision.
Look at comfort as well as safety
Ask how heating, fresh air, exhaust and temperature control serve the two dwellings. Some existing-suite arrangements differ from new construction requirements. A second furnace is not a universal test for legality, and the presence of two furnaces does not settle every ventilation question.
Alarms, electrical work and plumbing deserve the same evidence-based approach. Let the appropriate professional assess their installation and permit history. Then ask practical questions: who controls the thermostat, where are shutoffs, how is laundry used and what happens when one household needs service access?
Give the inspector a suite-specific brief
Send the listing, registry information and available plans before the appointment. Explain whether you intend to live upstairs, rent both spaces or renovate. Ask for attention to suite access, moisture, visible alterations, separation, systems and limitations. A generic request to tell you whether the home is good wastes an opportunity.
Afterwards, divide findings into immediate safety concerns, further investigation, priced repairs and comfort upgrades. Ask who can resolve each unknown and how long that may take. A good report becomes a buying decision only when the findings are connected to cost, timing and the terms of your offer.
Sources & next steps
Official references checked October 11, 2026. This guide supports your research; the City and the professionals advising on your property determine the applicable requirements.
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