What records explain additional residential units at a London home?
Section 4.37 of the Zoning By-law, with the temporary limits of Interim Control By-law CP-1600-300, as explained on the City's additional residential units page.
Sources checked October 28, 2026
The rule in London
Up to 4 homes on a lot
London zoning by-law Z.-1: permits up to four units in total (up to three additional units, up to two in a detached building) where a single, semi-detached, duplex, triplex or street townhouse is permitted (section 4.37); Interim Control By-law CP-1600-300 currently limits an additional unit to 80% of the main home's floor area.
From London by-law Z.-1, checked 5 Oct 2026
- The recordAdditional residential units
- Where to read itAdditional residential units
- The free check reads itPick “Extra units allowed”
What the record shows
The City's page says a residential property may have up to four dwelling units in total where the zoning allows single detached, semi-detached, duplex, triplex, converted or street townhouse dwellings: a maximum of three additional residential units per lot, only two of them in a detached building, and detached units only in the rear or interior side yard. The rules are in Section 4 of the Zoning By-law, including Section 4.37.
Some of those rules are temporarily superseded by Interim Control By-law CP-1600-300: while it is in effect an additional unit can't exceed 80% of the gross floor area of the primary dwelling, and each is limited to two bedrooms. Council adopted a zoning amendment on March 3, 2026 to make these changes permanent; that amendment is under appeal, and the interim by-law applies until the appeals are resolved. A building permit and a residential rental unit licence are required for every additional unit, and licensing includes inspections.
Where to read it yourself
- Additional residential units: the City's page: unit counts, the interim control by-law, permits and rental licences
What OfferDue covers in London
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 reads the lot's zone where the City's zoning map is open data we can use; where it isn't, the report's line says where the City publishes it. Neither is confirmation that a particular unit holds a permit or may be occupied.
Free check: pick “Extra units allowed” See the sample report
Public-record information, not legal, financial, insurance or inspection advice. Records change and can be incomplete, and this page describes the records, not any particular home. What we cover, city by city.