What records explain basement apartments, backyard units and fourplexes at a Guelph home?

By-law (2024)-21024 replaced section 4.12.1 of the Zoning By-law. A lot with a single detached dwelling may hold four dwelling units in total: up to three additional units in the house, or two in the house and one in a separate building, or one in the house and up to two in a separate building. Semi-detached, duplex and on-street townhouse dwellings may have additional units to a maximum of three units on the lot. The same by-law lists fourplexes, to a maximum of four units, as a permitted use in the RL.1 and RL.2 zones, and makes residential uses subject to confirmation of servicing capacity.

The City's page adds the limits on a detached building: it may hold up to two units, cover no more than 30 per cent of the yard together with other accessory structures, and stand up to 6.1 metres tall, and each detached unit can have up to 80 m² of residential floor area. One added unit needs no extra parking space; each further unit needs one more. Every unit needs a building permit, and the City requires each additional unit, including one built without a permit, to be registered under its Small Multi-Unit Residential Registration By-law. A permitted use in the zone does not make an existing unit lawful.

• Additional Dwelling Units (ADU): the City's page: lot types, detached units, parking, permits and registration
• By-law (2024)-21024: the zoning amendment for additional units and fourplexes (PDF)

Extra units allowed is in the free check as a summary of the City's rule, from our hand-kept table of city rules, and the full report adds the zoning line for the lot. Neither is confirmation that a particular unit holds a permit or may be occupied.

Free check: pick “Extra units allowed” See the sample report