Triplex conversion by adding a legal basement

5 Replies

Hello BP,

I purchased my first investment property in Brantford, ON.

It is a legal duplex, a 3 story detached house. The upper unit (2nd and 3rd floor) is approx 1500sqft and the lower unit (ground floor) is approx. 1000sqft. There is an additional 1000sqft of basement space a 700 of which is already finished but outdated. 

What I would like to understand is if anyone has had experience in converting an existing duplex to triplex in Brantford or other areas. I would like to convert the basement space into a legal basement apartment making this property a 3 unit property. 

Having connected with some people, I understand that my next step would be to work on getting a drawing. However, it seems that I would need to find and work with somebody that could come up with a drawing for the space and get the necessary permit with the city of Brantford. 

Does anyone have experience in a conversion like this? 

What would you suggest as the next steps?

Would you recommend anyone to help with my situation? 

Look forward to hearing your advice. 


Check to see what counts as an accessory dwelling in Brantford - this would be a triplex in all but name and might be easier permit wise.

I’m not sure for in Brantford but I know in Kingston wether it is a duplex or triplex, i’d go to the city and they will have multiple forms listing your next steps, everything from entrances to ceiling height. I know in Kingston as a contractor I do all the paper work for my clients, but if you plan on doing work yourself there will be a section that you sign off on saying you will be doing the work. Since it is your property you are eligible to do whatever work you’d like as long as it’s not a commercial building. All being said, if would start by going to the city and seeing what you need and where you need to start. 

You could check out SuiteAdditions run by Andy Tran. I’m not sure if they go as far as Brantford if you were to hire them. But they have a starters guide that you can use. I found it pretty helpful. Blog posts are also useful. Unfortunately I found it after I did my conversion in Mississauga, but now know better.