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Sela Developments

Home Additions in Calgary

A home addition in Calgary adds floor area to an existing house by building out at the back or side, building up with a second storey, or adding an attached garage, sunroom or covered porch. Every addition needs a City of Calgary building permit ($333.84 under 400 sq ft, $1,302.08 over), plus a development permit if the design does not meet the Land Use Bylaw. Sela Developments prepares the drawing set, manages the permits and builds the addition so it ties into the house.

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Building permit, under 400 sq ft
$333.84 (City of Calgary)
Building permit, over 400 sq ft
$1,302.08 (City of Calgary)
Building permit review
About 7 days (City estimate)
Development permit, if needed
About 10 to 12 weeks
Rear setback, most R-C1, R-1 and R-2 lots
7.5 m
Radon rough-in
Required under the new addition footprint
Placeholder image: home addition photo to come

01 · Overview

What a home addition in Calgary is

A home addition is new, enclosed floor area attached to an existing house. In Calgary it takes one of three forms: building out at the back or side on a new foundation, building up with a second storey or a room over a garage, or adding an attached garage, sunroom, covered deck or porch. The City of Calgary counts all of these as additions.

Every addition needs at least a building permit. The fee is $333.84 for an addition under 400 sq ft and $1,302.08 over 400 sq ft. If the design or its location does not meet the Land Use Bylaw, a development permit is needed as well. Electrical and plumbing work need separate permits. If the addition is 75% or more of the existing house’s square footage, the City notes home buyer warranty coverage may be required.

Detached buildings follow their own rules. A detached garage or a backyard suite is not an addition. On the City’s suite page, properties whose base land use changed from R-C1 to R-CG may now have both a backyard suite and a secondary suite.

02 · Before you start

What decides how a Calgary home addition gets built

Four questions shape the design, the permit path and the price.

01

Should I build out, build up or develop the basement?

Each direction trades one cost for another. Building out needs new footings and foundation, and it uses up yard and the room your lot allows. Building up keeps the footprint but loads the existing walls and foundation, and the roof comes off during framing. Building down, by finishing the basement, adds space without changing the outside of the house at all.

The use matters as much as the cost. A main floor family room or a larger kitchen usually wants to build out, at the same level as the rooms it joins. Extra bedrooms often fit better upstairs. A rec room, an office or a rental suite can go down. Lot size, the age of the house and how long you plan to stay all shift the answer.

How we handle it
02

What permits does a home addition need in Calgary?

A building permit always, and a development permit when the design does not meet the bylaw. The City estimates about 7 days for a building permit. A development permit takes about 60 days to a decision plus a 21 day advertising and appeal period, roughly 10 to 12 weeks. Development permit fees for a detached or attached house are $395 for 10 m² or less of developed area, or $775 over 10 m², plus a $472 service grades fee on most applications.

How we handle it
03

What drawings does the City need for an addition?

A full set. The City asks for a site plan showing the house, the addition and other buildings (a Real Property Report can be marked up for this), floor plans for each affected floor, elevations of every affected side, and structural cross sections through the wall, floor and roof assemblies with overall height. It also wants the manufacturer’s floor joist, roof and beam layouts, and engineering for anything outside the code’s standard rules. Houses built before 1990 need an asbestos abatement form, and new work must meet the Section 9.36 energy rules with a project summary form.

How we handle it
04

How does a new addition connect to the existing house?

Through the foundation, the roof and the wall. The new footings have to sit below frost so the addition and the house do not move differently through freeze and thaw. The new roof has to shed water past the old one without creating a valley that holds snow and ice. The weather barrier and flashing have to lap into the existing wall, and the cladding has to match. Under the new footprint, the City requires a radon rough-in.

How we handle it

03 · Key insight

Start with the lot and the structure, not the floor plan

Most additions are drawn as a floor plan first. The lot and the existing structure should come first, because they decide whether the project takes 7 days to permit or 10 to 12 weeks.

The Land Use Bylaw sets the box. In most R-C1, R-1 and R-2 districts the rear setback is 7.5 m. Side setbacks are 1.2 m on both sides on a laned lot, or 1.2 m on one side and 3 m on the other on a laneless lot. Parcel coverage is capped at 45% in districts such as R-C1, R-C2 and R-1. Projections into a setback are limited too. Inside that box, an addition needs only a building permit. Outside it, you are into a development permit, extra fees and a decision that is not guaranteed.

The house sets the other limit. A second storey is only as good as the foundation and walls under it. A rear addition is only as simple as the roof line it has to meet. Checking both before design costs a site visit. Finding out after the drawings are done costs a redesign.

04 · How we work

How we build your addition, step by step

  1. Answers 01Should I build out, build up or develop the basement?

    We check the lot and the house before choosing a direction

    We measure the lot against your district’s setbacks and coverage, look at the existing foundation, framing and roof, and compare building out, building up and developing the basement for your house. You get a recommendation with the trade-offs written down before any drawings are paid for.

  2. Answers 02What permits does a home addition need in Calgary?

    We apply for the permits and plan for the development permit clock

    We design to fit the bylaw where we can, so the job needs only a building permit. Where a relaxation is worth it, we apply for the development permit and build the 10 to 12 weeks into the schedule from day one. Electrical and plumbing permits are taken out by the licensed trades.

  3. Answers 03What drawings does the City need for an addition?

    We prepare the full drawing set

    Site plan, floor plans, elevations, cross sections, and the joist, roof and beam layouts from the manufacturer go in as one package, with the Section 9.36 energy form, the asbestos form for pre-1990 houses and any engineering the design needs. A complete package avoids the back and forth that one missing drawing can cause during review.

  4. Answers 04How does a new addition connect to the existing house?

    We tie the foundation, roof and walls into the house

    Footings go below frost on undisturbed soil, and the radon rough-in goes under the new slab. The new roof framing is laid out so water runs past the joint, with flashing and membrane at every tie-in. The weather barrier is lapped into the existing wall before cladding, then the new wall is finished to match the old. Matching stucco on an addition or siding on an addition is its own trade, and we plan it with the framing. Near a property line the code rules still apply: windows are generally not allowed within 1.2 m, and soffits are not allowed within 0.45 m.

05 · In short

Home additions in Calgary, planned from the lot up

A home addition in Calgary works when the lot, the structure and the permit path are settled before the floor plan is final. Every addition needs a building permit. A design that fits the bylaw avoids the development permit and its 10 to 12 weeks. Sela Developments runs the whole job as your general contractor, from drawings and permits to the tie-in and the final inspection.

If you would rather add space without changing the outside of the house, compare it with basement development in Calgary. Many additions make room for a bigger kitchen, which we cover in kitchen renovations. For the full range of interior work, see home renovations in Calgary. When you are ready, send us your address and we will check the lot.

Sources

2 cited
  • City of Calgary, Home additions (permit types, building and development permit fees, timelines, drawings, asbestos form, Section 9.36, setbacks, parcel coverage, radon rough-in, soffit and window rules, home buyer warranty).
  • City of Calgary, Adding a new secondary suite (backyard suite and secondary suite on R-CG properties).

Last reviewed October 22, 2026 by the Sela Developments team. See our editorial policy for how we write and check these pages.

FAQ

Questions we get asked

Short answers to what owners ask us most. Something else? Ask us directly.

Do I need a permit for a home addition in Calgary?

Yes. The City of Calgary says every addition needs at least a building permit. If the design or location does not meet the Land Use Bylaw, such as a setback or parcel coverage rule, you also need a development permit, and approval is not guaranteed. Electrical and plumbing work in the addition need their own permits.

How much are the City permit fees for an addition?

The building permit is $333.84 for an addition under 400 sq ft and $1,302.08 over 400 sq ft, including the safety codes fee. If a development permit is needed, it is $395 for 10 m² or less of developed area, or $775 over 10 m², plus a $472 service grades fee on most applications.

How long does it take to get a permit for an addition?

The City estimates about 7 days for the building permit review. An addition that needs a development permit takes about 60 days to a decision, then a 21 day advertising and appeal period, for roughly 10 to 12 weeks in total. The City notes these times are not guaranteed.

Is it cheaper to build up or build out?

It depends on the house. Building out needs a new foundation and room on the lot within the setbacks and parcel coverage limits. Building up avoids new foundation work but needs the existing foundation and walls checked for the extra load, and the roof comes off. We compare both against your lot and structure before design.

Does an attached garage or covered deck count as an addition?

Yes. The City of Calgary treats covered decks, porches, attached garages and sunrooms as additions, so they need a building permit and must meet the same setback and coverage rules. A detached garage or backyard suite is a separate building with its own permit requirements.

Related services

Check your lot before you design

Send the address and a few photos of the side of the house you want to add to. We check the setbacks, coverage and structure, then send a written quote with the permit path and schedule.

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