Home Additions in Markham

The City of Markham Building Standards Department handles the zoning check, the permit and the inspections; York Region looks after regional roads and servicing. Markham’s Site Alteration By-law 2011-232 covers larger sites; detached infill and additions go through the city’s Residential Infill Grading and Servicing (RIGS) review instead. An addition goes through RIGS, so its grading and servicing drawings are prepared for that review together with the permit set.

If the lot is in a TRCA Regulated Area, yes: building anything there needs a TRCA permit, and Markham will not issue the building permit until you have it. TRCA also asks for a pre-submission consultation, which we book as soon as the survey shows a valley or creek near the house.

Yes, if it fits the zoning, and that is the first thing we check. Markham’s Comprehensive Zoning By-law 2024-19 was approved by the Ontario Land Tribunal on September 19, 2024 on a city-wide basis, except for lands with remaining site-specific appeals, and is deemed to have come into force on January 31, 2024. Not every property in the City is covered by it, and owners can check the City’s interactive zoning map to see whether their property is affected. We run that check for your address first, then measure the addition against the by-law that covers the lot. If it misses a setback or the coverage limit by a little, we take a minor variance to the Committee of Adjustment before filing the permit.

Each district sets its own requirements, so the first question is whether your house is in one of them. Markham has four Heritage Conservation Districts protected under Part V of the Ontario Heritage Act: Thornhill, Markham Village, Buttonville and Unionville. For a house inside one, we ask Markham what that district requires of an addition and design to it.

Yes. We take on home additions across Markham, including Unionville and Thornhill, about half an hour from our Richmond Hill office. The first consultation is free, by phone or on site.

Three things to start: property address and a survey, if you have one; what you want to add and where; and photos of the side of the house and the yard where it would go. Send those and we tell you what the City of Markham Building Standards Department will ask for before we quote.

It can. A rear addition’s foundation is dug into the yard, and Tree Preservation By-law 2023-164 requires a permit before a private tree 20 cm or more across at 1.37 m above ground is injured, even one in poor shape, while City trees are covered too. We plot the trees from your survey before the footprint is fixed, so the addition can step around a protected tree, or the tree permit goes in before the Building Standards Department reviews the set.

It can if the lot has a detached, semi-detached or townhouse dwelling and is outside a GWY1 zone and TRCA hazard lands, which is where Section 4.9.9 of By-law 2024-19 allows additional units. An addition is part of the house, so a unit in it counts toward the two the house can hold, and it is drawn with the fire separation and exits a second unit needs.

No. Zoning is applicable law under the Building Code, so the Building Standards Department cannot issue the permit until the Committee of Adjustment has granted the variance and the decision is final. We prepare the permit set while the variance is heard, so it is ready to upload to ePLAN once the decision is in.

Usually, unless yours is recent and shows the house as it stands today. The setbacks and coverage under By-law 2024-19 are measured from it, and because an addition on an existing lot goes through Markham’s RIGS grading and servicing review, the existing grades a surveyor records are the starting point for that plan too. If you do not have a recent one, we can arrange it.