What is a bump-out addition and is it a good option for my Ottawa home?

A bump-out is a small extension along part of an exterior wall that adds a little floor area without the full cost and complexity of a conventional room addition. On a tight budget or a tight lot, it can be a smart way to gain the extra space a kitchen, bathroom, dining area or entry needs.

A key feature of many bump-outs is that they may not need a full foundation. A small extension can sometimes be cantilevered on floor framing that extends from the existing structure, avoiding excavation. Whether that works depends on your floor framing, the size of the bump-out and the loads, including snow, and an engineer or designer has to confirm it. Any bump-out that rests on the ground needs frost-protected support. Under the Code, footings on clay or soils that are not clearly defined must be at least 1.2 m deep and not less than the depth of frost penetration.

Cost is the main appeal. A bump-out is usually much less than a full addition, and a cantilevered one less than one with footings, but the price depends on size, structure and what's inside. Kitchens and bathrooms cost more because of plumbing, electrical and finishes. Treat any number as perspective and ask for itemized quotes.

Common uses include:

• Kitchen extensions that add enough depth along a back wall to fit an island or more counter.
• Breakfast nooks with a bench and windows.
• Bathroom expansions in small older bathrooms, adding room for a larger shower or tub.
• Entry vestibules, which are useful in Ottawa for managing snow, slush and cold air at the door.

On permits, don't assume a small bump-out is exempt. A building permit is required for an addition or alteration over 10 square metres (about 108 square feet) of building area, and the City's list also includes structural alterations, plumbing extensions, new windows where there were none and enlarging a window or door. Even work that doesn't need a permit must comply with the Building Code and Zoning By-law. If you're unsure, email Building Code Services at buildingpermits@ottawa.ca. Where a permit is needed, fees are $12.75 per $1,000 of construction value, minimum $117. Electrical work needs an ESA notification or permit, and gas work is done by a TSSA-certified gas technician.

Design matters. A poorly designed bump-out can look tacked on, so match the siding, windows and trim, and choose a roof form, often a simple shed roof, that ties neatly into the wall. To compare contractors, browse addition contractors in the Ottawa Construction Network directory.

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Looking for experienced contractors? The Ottawa Construction Network connects homeowners with qualified professionals:

• 613Bins
• RenoMotion Inc.
• MAK Construction and Development Inc
• Titley Construction
• Humble Homes - property maintenance

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