What size kitchen extension do I need to add an island in my Ottawa home?

A kitchen island is one of the features people ask for most often in a kitchen extension. It serves as prep space, casual dining, a homework station and the natural gathering point on long winter evenings. But an island needs more room than many people expect, and undersizing the extension leaves you with an island that feels cramped instead of useful.

A small island can be quite compact, but people building an extension often want something larger with seating. The critical measurement is not the island itself but the clearance around it. Kitchen designers commonly plan for roughly 42 inches of clear space on working sides, and more where two people cook at once, plus enough room on the seating side for stools to pull out without blocking a walkway. Your designer will confirm the clearances that suit your layout.

When you add the island to the clearances on every side, the room has to be both wide and long enough for traffic to move around it. If your current kitchen is a compact subdivision layout, getting a comfortable island in may mean extending by a meaningful amount, and the cost depends on the size of the extension, foundation, structure and finishes. Ask for itemized quotes that separate the extension shell from cabinetry and countertops, so you can see how island size and materials affect the total.

If you want a prep sink or dishwasher in the island, plan the drain routing early. It is easiest to rough in during the foundation stage; cutting into a slab later adds cost. An island with a cooktop needs a dedicated electrical circuit and ventilation, either downdraft or an overhead hood. Electrical work needs an ESA notification and is done by an electrical contractor licensed by ESA, and gas work is done by a TSSA-certified gas technician.

The Ontario Building Code doesn't regulate island size, but it does govern the extension. In clay or soils that aren't clearly defined, footings must be at least 1.2 m deep and not less than the depth of frost penetration. An addition of more than 10 square metres needs a City of Ottawa building permit; the 2026 fee for additions is $12.75 per $1,000 of construction value. Check your property's zone for setbacks and lot coverage before settling on the size.

A useful design idea is to put the seating side facing south windows or patio doors. People eat in natural light while the cook gets light over the shoulder instead of shadows on the counter, and Ottawa's low winter sun makes this noticeable from November through February.

Getting the size right from the start avoids an expensive redo. You can browse addition contractors in the Ottawa Construction Network directory at justynrookcontracting.com and compare quotes.

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