# How do I make a basement apartment legal in Hamilton?

> Making a basement apartment legal in Hamilton: the ADU building permit, fire separations, smoke alarms, exits, parking, a Fire Order and an inspection.

- Canonical HTML: https://www.jdtconstruction.ca/guides/legal-basement-apartment/
- Section: Home > Guides > Making a basement apartment legal
- Business: JDT Construction Inc., Hamilton, ON, Canada (serves Hamilton)
- Phone: (905) 818-0106 | Email: johnny@jdtconstruction.ca
- Page updated: 2026-11-05

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Guides

With a City of Hamilton building permit for an additional dwelling unit, a flat $515. The unit has to meet the Building Code: fire separations from the rest of the house, safe exits, windows, ceiling heights, interconnected smoke alarms and a duct detector that shuts the shared furnace off. If the Fire Department has issued a Fire Order, it is part of the application. JDT Construction plans the work around those rules.

## What does the Building Code ask of the unit?

The City lists these for an ADU inside a house [(City of Hamilton, Additional Dwelling Units, read November 5, 2026)](https://www.hamilton.ca/build-invest-grow/construction-renovation/residential-building-renovation/additional-dwelling-units):

**City of Hamilton Building Code checklist for an ADU inside a house**

| Item | What the City says |
| --- | --- |
| Age of the house | “Different Building Code rules apply depending on the age of the house.” |
| Fire separations | Required between the unit and the rest of the house |
| Heating | One furnace may serve both, with a smoke detector in the ducts that shuts it off; newer homes may need two systems |
| Smoke alarms | CAN/ULC S531, wired, interconnected, with a flashing light |
| Carbon monoxide | Detectors where there is a fuel burning furnace or an attached garage |
| Exits, windows, ceiling heights, room sizes | Minimums that depend on where the unit is in the house |
| Plumbing | Hot and cold water, sink, tub or shower, toilet, kitchen sink and access to laundry |
| Water service | May need a bigger pipe and meter; a lead pipe may need replacing |
| Septic | Allowed if the system can take the extra sewage, otherwise a permit to upgrade it |

## What if the Fire Department has already been?

Then the Fire Order goes with the permit application. The City: “Apply for building permit in the normal manner with the Building Division. With your application form include the Fire Order Number for reference in the description of work. Submit a copy of the Fire Order and architectural drawings reviewed, approved and stamped by the Fire Department.” [(City of Hamilton, Additional Dwelling Units, read November 5, 2026)](https://www.hamilton.ca/build-invest-grow/construction-renovation/residential-building-renovation/additional-dwelling-units) An owner can also ask the Fire Department for a paid inspection: $733.10 with HST for a house with two dwellings in 2026, including a compliance letter [(Hamilton Fire Department, Residential and Commercial Inspections, read November 5, 2026)](https://www.hamilton.ca/home-neighbourhood/emergency-services/fire-department/fire-permits-inspections-reports-and-5).

## Does it need parking, or development charges?

Usually neither. The City says that under its amended by-laws “additional parking spaces for up to 3 units are now exempt”, with more review for newer buildings [(City of Hamilton, Additional Dwelling Units, read November 5, 2026)](https://www.hamilton.ca/build-invest-grow/construction-renovation/residential-building-renovation/additional-dwelling-units). And the 2026 to 2027 development charges include a 100% exemption for up to two ADUs in a house ([development charges](https://www.jdtconstruction.ca/guides/development-charges/)). The zoning still decides how many units the lot may have: [can my house have an ADU?](https://www.jdtconstruction.ca/guides/adu-eligibility/)

## Why bother?

Because the alternative is an order: [building without a permit](https://www.jdtconstruction.ca/guides/building-without-a-permit/) lists what the City can do, including an order registered on title. A permitted unit also gets its own municipal address.

## How does JDT approach it?

JDT draws the house as it is and what has to change, then prices the whole of it in one written proposal. The [ADUs page](https://www.jdtconstruction.ca/builds/adus/) covers the bigger picture, and [finishing a basement](https://www.jdtconstruction.ca/guides/basement-permit/) covers basement work that is not a unit. Under JDT Construction Inc.'s agreement the homeowner applies for the permit and pays the City's fees; [who applies for a building permit](https://www.jdtconstruction.ca/guides/building-permits/) explains how that works.

Published by JDT Construction Inc., Hamilton. Updated November 5, 2026. Free to share and quote, with a link back to this page.

## An apartment to legalize?

Send photos of the unit and the house. JDT draws what has to change and prices it in one written proposal.

[Call (905) 818-0106](tel:+19058180106) [Request a quote](https://www.jdtconstruction.ca/request/?problem=adu)

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JDT Construction Inc. Call (905) 818-0106. Full site: https://www.jdtconstruction.ca/