Side Yard Clearance Stops More Richmond Hill Suites Than Height

Second units and basement work in Richmond Hill

In older Toronto and older Mississauga stock, the first question on a legal suite is always whether the basement can be made tall enough, and the answer is usually underpinning or a bench footing. In Jefferson, Rouge Woods, Westbrook, Devonsleigh, Observatory and most of the Oak Ridges subdivisions, the poured walls already give you the headroom. Underpinning in Richmond Hill is the exception, not the starting point. Older pockets are the other story — Mill Pond, Crosby, Harding, Langstaff and the Yonge Street core have plenty of 1950s and 1960s houses with shallow, block-wall basements where the height genuinely does need to be bought.

What actually kills jobs in Richmond Hill is the side yard, not the ceiling.

Richmond Hill's additional residential unit by-law (143-24, passed December 2024) is specific about how a person gets to a side or rear entrance. You need a clear access path at least 1.0 metre wide running from the street or lane all the way to the unit door, hard-landscaped along its entire length, with 2.1 metres of vertical clearance and no encroachments in it. On a 1990s or 2000s subdivision lot with a 1.2 metre side yard, that path is exactly where the AC condenser, the gas meter, the hose bib and the downspouts already live. Half the Richmond Hill site visits we do are really a measuring exercise on that strip.

Where the side yard genuinely won't give it up, the by-law leaves a door open: entrances below grade or oriented perpendicular to the street are permitted on the front elevation even beyond the normal two-entrance limit. That is often the honest answer on a narrow Rouge Woods or Devonsleigh lot — a front walkdown instead of a side entrance.

Our separate entrance and walkout work is typically built in three days: cut, excavate, form and pour the well and stairs, set the door, waterproof and backfill, and get the site tidy. That is the flagship. From there we handle the full legal second unit — framing, fire separation, egress windows, HVAC, plumbing, electrical rough-in and ESA, kitchen and bath, and the inspections through to occupancy. We also build garden suites and garage conversions, home additions, and full home renovations.

HMH Construction Inc. runs out of a Mississauga head office, has been at this for 25+ years, is WSIB covered and fully insured, and does the permit work in-house so you are not chasing a designer and the Building Division yourself.

Call 905-749-4608 for a look at your lot.

Richmond Hill requirements

WHAT RICHMOND HILL ALLOWS (By-law 143-24, passed December 11, 2024)

- Up to three additional residential units (ARUs) per lot, to a maximum of four dwelling units total including the main house. No more than two of those ARUs may be inside a detached accessory residential building. - Permitted in single detached, semi-detached, link, duplex, triplex, and most townhouse forms — including street, block and rear-lane townhouses. - The lot must be separately serviced by the municipal sewage works and the municipal drinking water system. Lots on a well or septic in the rural north end are out, full stop. - An ARU cannot be accessed only through a garage, attached or detached. - Home occupations are not permitted inside an ARU.

Entrances

the rule that decides most Richmond Hill jobs

- Side, flankage or rear yard access requires a clear access path from the street or lane to the unit door: minimum 1.0 m wide, hard landscaped along its entire length, 2.1 m minimum vertical clearance, no encroachments. Where a unit has more than one access, at least one must meet this. - A side elevation entrance needs at least 1.0 m from the side lot line to the door, plus that clear path. - On the front elevation, a maximum of two above-grade entrances parallel to the street. Entrances below grade, or oriented perpendicular to the street, are not counted against that limit — which is what makes a front walkdown viable on tight lots.

GARDEN SUITES / DETACHED UNITS (Accessory Residential Building)

- One accessory residential building per lot, rear yard only. Not permitted in a side, flankage or front yard. - Building coverage capped at 80.0 m² (861 sq ft), including any integral garage. - Maximum two storeys; main wall height max 6.0 m above average grade; overall height max 7.5 m to the peak. - Minimum 1.2 m side and rear yard setbacks; minimum 4.0 m between the suite's main wall and the house's main wall. - Minimum 50% of the rear yard must remain soft landscaping — interlock and permeable pavers do not count. - No rooftop amenity areas. No other detached accessory structures allowed on the lot except bicycle parking, so the existing shed usually has to go. - Lots with a lawfully existing detached garage closer than these setbacks can generally inherit those existing setbacks. - The City offers pre-approved detached ARU reference models, which shortens the permit path if one fits your yard.

PARKING

- Required parking is set by a schedule area map, ranging from none to three total spaces per lot depending on where you are — a Yonge corridor lot and a Bayview Hill lot are not treated the same. Tandem spaces count. - Lots under 9.0 m frontage are never required to provide more than two spaces. - In three of the four schedule areas, one long-term weather-protected bicycle parking space is required per ARU.

WHERE ARUs ARE NOT PERMITTED

- Floodplain (F), Low Land (LL), Open Space, Environmental Protection Area 1 and 2, Oak Ridges Moraine Natural Core, Oak Ridges Moraine Natural Linkage, Major Urban Open Space, and lands in the Greenbelt Plan Natural Core designation. - Oak Ridges Moraine Countryside and Oak Ridges Moraine Hamlet zones: one ARU only, and only in a single detached dwelling. - Agricultural (A1): one ARU only, and only in an existing dwelling or existing accessory building. - Properties in a TRCA regulated area need TRCA approval before a permit. TRCA identifies part of Oak Ridges — from Lake Wilcox west to the Humber at Bathurst — as a Flood Vulnerable Area. Around Lake Wilcox this matters twice over: zoning may rule the suite out entirely, and the moraine's sand-and-gravel soils and shallow water table make drainage design on a walkout a real engineering item rather than a formality.

ZONING IS MID-TRANSITION RIGHT NOW

Richmond Hill spent decades under 40-plus area-specific zoning by-laws going back to the 1960s. Comprehensive Zoning By-law 93-25 was passed September 24, 2025 to consolidate them, and the Ontario Land Tribunal granted it partial approval on July 2, 2026 — with appeals still active on other lands. So as of today, which by-law governs your setbacks and parking depends on your specific property, and some lots sit under both during the transition. This is the first thing we confirm on a Richmond Hill site visit, before anything gets drawn.

REGISTRATION AND PERMITS

Richmond Hill does not appear to run a separate second-suite registration or licensing program the way some GTA municipalities do — we could not find one on the City's site. The legal record of your unit is the building permit, the inspections and the final occupancy permit. You will also need a separate ESA electrical permit, and a site alteration permit if a detached structure exceeds 400 sq ft. Building Division: 905-771-8810.

HERITAGE

Gormley is Richmond Hill's only Heritage Conservation District, in effect since December 2009. Elsewhere, heritage is property-by-property through the City's Heritage Register. Mill Pond in particular has a lot of listed and designated houses on large lots. On a designated property, alterations need written Council consent through the heritage permit process before a building permit — worth checking early, because it adds real time.

BACKWATER VALVE SUBSIDY

The City subsidizes up to $1,500 toward installing a backwater valve on an existing single-family, duplex or triplex home. It requires a licensed plumber, a City building permit before the work starts, a City plumbing inspection after, and eavestrough downspouts disconnected from the City sewer. On a combined system the storm weeping tiles have to be disconnected and directed to a sump pump. Applications must be in within six months of completion, and funding is first-come, first-served. If we are already opening the basement floor for a suite, that is the cheapest moment in the project to do it.