Decks, Constructions, Permits

The following is a brief and legal summary of the City of Markham's Deck By-law taken from the City's By-law Guide for Markham Homeowners.

It explains, in plain language and with information links, what residents must know about specific City services and operations, which may affect a Markham homeowners' property.

Decks And Buildings By-law Summary

In Brief

The City of Markham’s building standards ensure a high level of quality in the design and construction of all our buildings and structures. If you plan to build a new house, tear an old one down, or do major repairs and renovations to your home, you must contact the City of Markham’s Building Standards Department to get a building permit before you begin.

What You Must Know

Below is a brief overview of what does, and does not, require a building permit. If you aren’t sure whether your project will require one, contact the Permit Application Administrator’s Desk at 905-475-4870 with the details of the work. A more detailed explanation of the building permit process is also available from the Building Standards Department.

Before you can get a building permit, the Building Standards Department will ask you for a lot of very specific information. This process is designed to ensure that every construction project in Markham meets the requirements of the Ontario Building Code and all applicable laws, including the City’s zoning bylaws.

All Signs

All signs you wish to install on your property require a building permit (Note: signs which advertise a home-based business cannot be displayed on your home’s property).

Additions, Renovation, Demolition or Construction of an Entire Home

Most construction work will require a building permit.

This includes all detached or attached garages, carports, solariums and sunrooms, constructing a ‘separate suite’ or fully independent apartment within your house, structural alterations such as adding or removing a basement column or structural wall in a house, creating a dormer (a gabled extension built out from a sloping roof, usually with a vertical window in it), and raising a house to provide a full basement.

Construction that will change the use of a house, such as turning it into a place of business, also requires a permit.

Accessory Buildings

A new shed, sauna or other accessory building won’t require a building permit if has a ‘footprint’ (the space on the ground that the building will take up) less than 10 metre2 (108’ square). Anything larger will require a building permit.

Calculating your building’s ‘footprint’

From the plans, or instructions, determine what the finished length and width will be (in metres or feet). Calculate the ‘footprint’ by multiplying the length by the width. This equals the area of the building, which is also the ‘footprint.’

Creating a deck in your rear yard--one that’s not attached to the dwelling and less than 10 metre2 (108’ square) in area (see Calculating your building’s footprint above)--does not require a building permit. You do need a permit for all decks larger than this, for decks directly attached to your house, and for decks more than 600 millimetres (2’) above the ground. See Site Alteration By-law Summary for information about protecting drainage when you build your deck.

New Plumbing, Heating or Sewage Systems

If your planned work includes installing new plumbing, you will need a building permit. Replacing existing taps, tubs, toilets, or sinks does not require a permit, but adding new ones where there weren’t any before, or any work that alters or repairs the pipes in your home’s plumbing system, will require a building permit.

If you intend to install an on-site sewage (septic) system, or make repairs to one, you will need a building permit.

Replacing an existing furnace with the same kind does not require a permit, but if you want to change your furnace to another fuel source, such as changing from electric to natural gas, you need a building permit. You also need one if you plan to install a new ‘solid fuel burning appliance,’ for example a wood-burning stove or fireplace.


Retaining walls less than 1m (3’- 3”) in height won’t require a building permit. Retaining walls higher than this, attached to a building, or located next to a public walkway, will have special restrictions. Contact the Permit Application Administrators desk for more information.

Creating sidewalks, planters and other general landscaping in your yard doesn’t require a building permit, but you must take into consideration the way surface water drainage occurs on yours and surrounding property.(See Site Alteration By-law Summary for information about protecting drainage.)

Replacing Appliances Adding air conditioning units or heat pumps to an existing system, or replacing an existing furnace or hot water heater, does not require a permit. However, please note the requirement to limit hot water in your tank to 49°C (120°F).

General Maintenance and Decorating

Other work that doesn’t require a building permit: all general painting and decorating plans, including putting up new kitchen or bathroom cupboards; and general maintenance including installing new roof shingles on your home.

When in doubt, check it out! Help is always available.

Contact the Permit Application Administrators desk at 905-475-4870 for more information.

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