It’s an excellent question; one we get all the time. And, for the record, we always encourage people to build as big of a garage suite as possible on their lot to maximize the value of their dollar while reducing the cost per square foot. However, there are limitations to the size of your laneway house in Calgary.

Below, we discuss several factors that may allow you to go bigger or keep you within the city guidelines for these types of projects.

City of Calgary Maximums

According to the City of Calgary, the maximum allowable building envelope for a garage suite is 75 square meters, or about 804 square feet. Additionally, the maximum living space has been set at 850 s.f. But can you go bigger?

Yes, in many instances, you can design and build a laneway house that is larger than the city’s maximums; we’ve completed many projects that exceed these maximums. Here are a few pointers and situations where that may be more plausible, and not.

#1 – If Your Lot is Large, You’re in Luck

In our experience, the larger the lot you have, the more likely the city is going to provide you with a “relaxation” on the size of the garage suite. Therefore, let’s say you have a large pie-shaped property with the wider side facing the alley, and your R-CG lot coverage comes in well under your 45% maximum. Then, the city is more likely to say “yes” to your expanded design.

Keep in mind that shadowing rules and other land use bylaws still apply; however, typically with larger lots, these other factors that could restrict your suite’s design play a minimal role.

#2 – Can’t Be Bigger than the Main House

A hard red line for the City of Calgary’s planning department is that a garage suite cannot be the same size or larger than the main house (envelope) in any way. Additionally, in our experience, the suite cannot approach or match the size of the main house.

Say, for example, that you live in the Seton community and your main house’s envelope is about 900 square feet. In this case, you should be alright to get a maximum-sized suite at 804 s.f. of envelope and 850 s.f. of living space. But, having said that, we recommend not to push it any further than that.

#3 – Lot Coverage Restrictions

The City of Calgary’s recent zoning change to a majority R-CG lots opened up more opportunities for homeowners, especially those with existing basement suites, to build a laneway house. However, having said that, lot coverage maximums remain relatively the same.

If you owned an R-C1 or R-C2 property that converted to an R-CG and want to build a backyard suite, your lot still adheres to a 45% coverage maximum. This is not to be confused with multi-family projects, as these types of builds are subject to a different set of rules for R-CG zoning.

In some cases, the city may permit a backyard suite design exceeding 45%. However, we haven’t seen any relaxations provided for R-CG lots with a potential garage suite build that have gone above 50% coverage. Applying for any design above your coverage maximum will be considered a “relaxation,” and is not guaranteed to be approved.

If you have different zoning than R-CG, make sure to check the city’s land use bylaw to learn more about your lot coverage restrictions.

#4 – Garage Suites in other Municipalities

When in doubt, it’s always a good idea to consult an experienced designer or architect who has designed and permitted for garage suite projects in your respective municipality before. They are likely to be more familiar with technical rules that would come in to play and restrict the size of suite you can build.

In Rocky View County, for example, which obviously follows a set of separate rules, the maximum allowable living space for backyard suites (acquired from the planning department in June of 2025) is just above 1,600 square feet.

Therefore, as you can see, the maximum allowable size for rural areas is much larger. We’ve built a few projects in Rocky View with around 1,100 to 1,200 square feet of living space to date, one near Cochrane and the other in Springbank.

Airdrie and Cochrane, two municipalities we get a lot of inquiries from, also have their own set of rules on the maximum allowable size of laneway houses. Make sure to familiarize yourself with their rules before proceeding with any design and permit!

#5 – Don’t Get Greedy on Size

Even if you have a large lot, it is crucial not to overstep the municipality’s boundaries. They may look at the design and say it is pushing the envelope too far, and make you revert back to their soft maximum of 804 s.f. envelope, 850 s.f. living space.

Having said that, in our experience, the building envelope can be pushed up to 900-950 s.f., and the living space can be relaxed in many instances by about 10%, up to around 880 s.f. or more. However, pushing your garage suite’s size larger than this can be risky, especially if the municipality feels you’re going too far.

Remember, Permits are Discretionary

Please note that every garage suite design and permit is discretionary in nature (meaning it could be “yes” or “no”) and is at the whim of the city planning department for approval. The situations described above are based on many years of experience, and we’ve shared these with you to provide insight into the allowable size of backyard suites.

These scenarios may or may not reflect your personal design and permit process; it is essential to note that each is evaluated on a case-by-case basis by various individuals working for the municipality who may stick to the book or be more lenient. Additionally, please note that the city’s land use bylaws are set to change at any time.

Questions about Garage Suites in Calgary?

contact garage suites Calgary today

If you have questions about your backyard suite build, don’t hesitate to contact us today anytime at 403-797-4918 or info@garagesuitescalgary.ca and we will be happy to assist you! We look forward to connecting with you to discuss your garage suite goals!