Want a tiny home or coach house in your backyard? Here’s what you need to know.

Recent rule changes have made backyard dwelling units more viable. But there are still a lot of regulations to steer through.

As the cost of housing quickly rises, home ownership is being put out of reach of many people in Peterborough. And renting appropriate housing has also become prohibitive in many cases.

There are a lot of different forces behind Peterborough’s rising housing costs, but two of them are low housing supply and a lack of diverse housing options. Encouraging infill development in areas that are already built-up could help to address this, and one way to achieve that kind of development is by building accessory dwelling units, or ADUs. An ADU is a second unit on a residential property that already has one house on it.

“We’re really lucky in Peterborough that there are pretty large areas of the city where the lots are extremely generous in size,” says Chris Magwood of the Endeavour Centre, a sustainable building school in Peterborough. 

Those generous lot sizes provide an opportunity to “improve the density of the city without having to keep ripping up farmland around the perimeter and turning it into subdivisions,” Magwood says. “That seems like a better approach to make use of what’s here.”

To help facilitate infill development like this, the City of Peterborough (at the direction of the province) passed a new bylaw in 2018 that made ADUs legal for any residentially-zoned property in the city. 

That bylaw not only legalized second apartments within already existing houses; it also legalized detached dwelling units. That means you can build a second residential structure on your property — provided you meet a series of requirements and follow regulations (see below).

For Esther Vincent, the new bylaw made it possible to finally realize a vision she’d had for her property for over 20 years: converting her century-old concrete-block garage, which had fallen into disrepair, into a studio apartment.

“The idea of having a built structure downtown that was lying fallow didn’t seem like it was a very wise use of time, space or resources,” Vincent says. So, she thought, “this should become functional as a living space for people.”

With ADUs legalized, Vincent worked with the Endeavour Centre to design and build a simple and pleasing living space that is also environmentally-friendly, accessible and durable. Vincent continues to live in the main house, and she rents out the new apartment, which is helping to cover the up-front cost of the build.

BEFORE: When the City of Peterborough legalized accessory dwelling units in 2018, Esther Vincent decided to convert her 100-year-old garage into a studio apartment. (Photo courtesy of the Endeavour Centre)
AFTER: With help from the Endeavour Centre, Vincent realized her vision of a low-carbon dwelling unit. (Photo courtesy of the Endeavour Centre)

Before getting started on Vincent’s build, Magwood familiarized himself with the City’s new ADU regulations. He feels the planning department did a good job developing the regulations. 

But he’s got a few suggestions, too. First, Magwood would like to see multiple units permitted in a single ADU. Right now, only one unit is permitted. With additional units bringing in rental income, building an ADU becomes much more financially viable, he says. Secondly, rather than simply allowing ADUs, he’d like to see the City actively incentivize them, perhaps through a loan program that helps with the upfront capital costs.

Slow uptake on detached ADUs

Earlier this year, the City reported to the CMHC that 135 secondary suites were created between the new bylaw taking effect in 2018 and December 2020.

But the vast majority of those were created within an already existing building — like Vincent’s converted garage or a new basement apartment, for example.

According to the City’s zoning administrator Andrea Stillman, only two permits have been issued to date for a new detached ADU on a residential property.

Why so little uptake?

One likely reason is that until last fall, the City still levied development charges on detached ADUs. Peterborough’s supervisor of development and planning, Brad Appleby, says that those charges could have added as much as $37,000 to the cost of a build. 

But in September, the province implemented a development charge exemption for detached dwelling units, meaning the City can no longer charge for those kinds of developments.

That means building a detached dwelling unit on your property just became a whole lot cheaper.

Stillman says that over the last couple of months she’s seen an uptick in inquiries about detached ADUs, and that the waived development charge might be a contributing factor. She expects the number of permits issued for detached ADUs to “increase substantially” this summer.

Gary Hibbert, a Durham-based realtor and real estate investor who owns properties in Peterborough, says he and his clients are excited by the new opportunities to build more rental units on a single property.

“Many of our investors started converting,” their Peterborough properties after the 2018 bylaw was passed, he says. “And now we’re also looking at the garden suite option.” (Garden suite is another word for a detached ADU.)

Hibbert suggests a second reason for the recent uptick in interest in detached ADUs. Currently, Peterborough’s bylaws allow for either a secondary suite within an existing home or a detached dwelling unit elsewhere on the property, but not both. At the direction of the province, the bylaw will be revised to allow both in the near future, and Hibbert says that has him looking more closely at detached ADUs.

Considering building an ADU on your property? Here’s what you need to know.

If you’re interested in building an ADU of any kind on your property, Appleby recommends familiarizing yourself with the regulations first, because it’s possible that your property isn’t eligible for this kind of development.

And Vincent advises people to “start early, ask lots of questions and be prepared for lots of paperwork.”

To get you started, here are some of the most important regulations that you need to keep in mind right from the beginning. 

Unfortunately for those inspired by the trend of tiny house living, many of these regulations are likely to stymie your vision of building a tiny house on wheels. But the regulations still allow for other creative and innovative housing solutions like Vincent’s.

Minimum square footage
The City requires all new dwelling units to have at least 301 square feet of floor area. That’s quite small, but it would still disqualify the kinds of tiny houses that have become a fascination on Instagram and Youtube, which are sometimes as small as 150 square feet.

Appleby says the minimum size requirement was inherited from a previous zoning bylaw, and that the City could nix the idea of a minimum size requirement sometime in the future. If that happened, structures would only have to comply with provincial building code’s size requirements, which can allow for smaller designs. 

Stuck in place
In Peterborough detached ADUs must be built on a fixed foundation. That means no wheels and no portability. Appleby says that a structure on wheels would be considered a trailer, and that those are only permitted in designated trailer parks.

Connected to services
According to the city’s bylaw, a detached dwelling unit must be connected to municipal services including water, sewer and electricity. The City imagines that in most cases this would be accomplished by connecting the ADU to the primary residence, but it would also be possible to establish a new independent connection to City services.

Unfortunately for those looking to build a more sustainable structure, this requirement means that off-grid living isn’t coming to Peterborough anytime soon.

Keep it dry
Detached dwelling units are not permitted in a floodplain. Your property might require a study by Otonabee Region Conservation Authority to determine whether it is in a floodplain or not.

Lot coverage
All the accessory buildings on your lot — including sheds and other non-residential accessory buildings — must cover less than 10 percent of the total lot size. That means you’ll need a relatively large lot to start with.

Unless your property is in the downtown core, you’ll have to provide an additional off-street parking space for the accessory dwelling unit.


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