Markham Addition Site Plan for Permit: Setbacks, Lot Coverage, and Existing Structures

Planning a home addition in Markham? Whether you are adding a rear addition, side addition, family room, mudroom, garage extension, or extra living space, the permit review usually needs a clear site plan. The City needs to understand where the addition will go, how close it is to property lines, how it affects lot coverage, and how it relates to the existing house and other structures.

That is where a clear Markham addition site plan for permit becomes important.

A site plan shows your property from above. For an addition project, it should show the proposed addition, existing residence, property lines, setback distances, lot coverage calculation, driveway, porch, deck, landscaped areas, existing structures, north arrow, scale, and any site details needed for zoning and building review.

Does a Home Addition Need a Permit in Markham?

Usually, yes. A home addition changes the building footprint, floor area, structure, exterior walls, and sometimes grading, drainage, lot coverage, parking, and setbacks. City of Markham says homeowners should confirm whether a project needs a permit and which zoning requirements and applicable laws apply before planning the project. City of Markham

Markham also says its zoning bylaws cover land use, building use, structure size, height, location, and more. The City specifically notes that zoning bylaws tell you how close to the lot line you can build. City of Markham

That means a home addition is not reviewed only as a construction project. It also needs to fit the zoning rules for the property.

Why a Site Plan Matters for a Markham Addition

A site plan helps the reviewer understand the full property layout. It is not just a box labelled “addition.” It explains how the proposed addition fits with the existing house, lot lines, setbacks, driveway, porch, deck, landscaped area, and total building coverage.

A good addition site plan helps answer questions like:

• Where is the proposed addition located?
• How large is the addition?
• How far is the addition from the side, rear, and front property lines?
• Does the addition affect lot coverage?
• Does it connect to an existing wall, porch, deck, garage, or driveway?
• Are existing structures shown clearly?
• Does the project affect drainage, grading, access, or landscaped area?
• Is the drawing clear enough for permit review?

If these details are missing, the permit review can slow down because the reviewer may need corrections or more information.

What Your Markham Addition Site Plan Should Show

A strong site plan should be clean, scaled, and easy to read. It should show both existing conditions and proposed work so the reviewer does not have to guess what is already there and what is being added.

Your site plan should usually include:

• Property lines
• Lot width and lot depth
• Existing residence footprint
• Proposed addition footprint
• Existing deck, porch, driveway, garage, shed, patio, or other structures
• Front yard, rear yard, and side yard setback dimensions
• Distance from the addition to nearby structures
• Lot coverage calculation
• Driveway and hard surface areas
• Landscaped area
• Grading or drainage direction, if relevant
• Easements or services, if known
• North arrow and scale

1. Proposed Addition Location

The proposed addition should be clearly shown and labelled. Use a simple label such as “Proposed Addition” and show the actual footprint of the new work.

Helpful addition details include:

• Addition length
• Addition width
• Total addition area
• Whether it is one storey or multiple storeys
• Where it connects to the existing residence
• Whether any existing deck, porch, or wall is being removed or changed

The reviewer should be able to look at the plan and immediately understand what is existing and what is proposed.

2. Property Lines and Lot Dimensions

Property lines are one of the most important parts of an addition site plan. They show the legal edges of the lot and allow setbacks, lot coverage, and overall building placement to be checked.

Your plan should show:

• Front property line
• Rear property line
• Left side property line
• Right side property line
• Lot width
• Lot depth
• Any irregular lot shape

If the addition is near a side or rear lot line, the distance should be labelled clearly. A rough sketch that says “addition on side of house” is not enough for a proper review. Tiny dimension labels are boring, but they do the permit heavy lifting.

3. Setbacks From Lot Lines

Setbacks show how far the building is from the property lines. For an addition, this is usually one of the first zoning items reviewed.

City of Markham says zoning bylaws cover structure size, height, location, and how close to the lot line you can build. City of Markham

Your site plan should show:

• Front yard setback
• Rear yard setback
• Left side yard setback
• Right side yard setback
• Setback from the proposed addition to the nearest lot line
• Setback from existing building walls, if relevant
• Distance from roof overhangs or projections to lot lines, if required

For side additions, side yard setbacks are especially important. For rear additions, rear yard depth and distance to the rear lot line usually matter most.

4. Existing Residence

The existing residence should be shown clearly. The proposed addition should connect logically to the existing footprint so the reviewer can see how the house will change.

Your site plan should label:

• Existing residence
• Existing garage, if attached
• Existing porch
• Existing deck
• Existing entry points
• Walls affected by the addition

This helps separate the existing house from the new addition. Without that distinction, a reviewer may not know what changed.

5. Existing Structures on the Property

An addition site plan should show more than the house. Existing structures can affect setbacks, lot coverage, access, drainage, and construction space.

Show existing features such as:

• Deck
• Porch
• Garage
• Shed
• Carport
• Patio
• Pool or hot tub, if present
• Retaining walls
• Walkways and steps

If an existing deck or porch is being removed to make room for the addition, label that clearly. Existing-to-be-removed items should not be confused with existing-to-remain items.

6. Lot Coverage

Lot coverage is one of the biggest zoning concerns for home additions. It measures how much of the lot is covered by buildings or structures, depending on the zoning definition that applies to the property.

Markham’s Comprehensive Zoning By-law includes standards and definitions that can affect building size, setbacks, height, yards, landscaping, and other zoning items. The City notes that not all lands are subject to the new Comprehensive Zoning By-law 2024-19, so homeowners should confirm the zoning that applies to the specific property. Your Voice Markham

Your site plan may include a lot coverage table showing:

• Total lot area
• Existing residence area
• Proposed addition area
• Existing porch area
• Existing deck area, if counted
• Garage or accessory structure area
• Total coverage after the addition
• Lot coverage percentage

For an addition, this table can be very helpful. It lets the reviewer see the before-and-after impact quickly.

7. Driveway and Hard Surface Areas

The driveway should be shown because additions can affect parking, access, hard surface coverage, and the overall front yard layout.

Your site plan should show:

• Driveway location
• Driveway width
• Garage location, if any
• Walkway to the front door
• Patio or paved areas
• Any hard surface near the proposed addition

If the addition affects the driveway, parking area, or access path, show the change clearly.

8. Landscaped Area

Landscaped area helps explain how much open yard remains after the addition is built. It can also help reviewers understand drainage, access, and site layout.

Your site plan may show:

• Lawn areas
• Garden beds
• Trees and shrubs
• Side yard access
• Rear yard open space
• Areas affected by construction

For additions on tight lots, landscaping and open space can become part of the zoning review. The plan should not make the new addition look like it was dropped into the yard by helicopter.

9. Grading and Drainage