Types of Building Alterations

December 12, 2023

Types of Alterations

Sam Leika-Shukor (Issam), OAA, AAA, AIBC, CPHD, RAIC, innovative sketch design architect & Certified Passive House Designer

There are several types of building alterations. When you apply for a permit most of the categories can fall under umbrella expressions, either "additions" when it involves increasing the buildable area, or "interior alterations" for work inside the building envelope. But if you have a vacant land or intend to demolish your existing building and build from scratch, it falls under "new build".

Change of Use

The first type of the building alterations is the change of use. Change of use is generally when you're turning a use or category into another. Example would be you're changing an office space into residential unitl, an industrial loft into a gallery, or a group of residential units into a bank. This type of change of use requires re-zoning if the area doesn't allow for a change of use.

A sketch showing Change of Use for a building from Retail to a Commercial units.


The second of these types is addition or extension to an existing structure, house or building. this is the most commont type. Most of people eventually would need to expand their homes since they bought it. Expansion to the rear of the property especially when the Gross Floor Area or footprint allows, is the most common. Adding an extra bedroom, a solarium in the back linked ot the kitchen, or expanding the living space, or even adding an enclosed swimming pool would all be "additions" to your existing structure or building. this could improve the functionality of the space but could also change the whole atmosphere of the interiors because it requires rearrangement of the spaces slightly to accommodate the new expansion.

Adding A Dorm

The third is adding a dorm on the upper floor, expanding the main floor building toward the backyard, or "topping up" an exsiting bunglow with a second or third floor if the Gross Floor Area, maximum height or other restrictions allow.

A sketch showing sective (sectional perspective) through a space that went under Interior Alteration.


Building alteration normally involves partial demolition, retrofitting, or upgrading a component or feature of acomponent in the existing building. An example of that is to improve the thermal resistance (insulation) of all exterior walls or ceiling or slabs-on-grade by adding more insulation. Refurbishment or remodelling of a component also fall under the retrofitting category as it upgrades the whole space or exterior element (such as modernizing the exterior facade with modern material or features -another common retrofit). In general though upgrading is rarely done without some sort of other types of building alteration such as interior alteration, expansion, addition, or even performing two types of retrofits at the same time (improving insulation on all exterior walls while doing a kitchen remodelling for example).

Interior Alteration

The potential of linking existing spaces together (opening up a wall to create an opening) or separating spaces by closing off doors or adding dividing walls to create an extra room or rooms is also a type of building alteration that you need to know about. This is usually falls under "interior alteration" per the City of Toronto or other building department / jurisdictions in Canada.


Renovation as a type of building alteration is when you improve the building's existing components or features without changing them. The repair of an existing component or feature however is not called a renovation but a repair work (i.e. priming, sanding, and painging a damaged wall for example) which can also be called maintenance to lengthen the life span of the component. Decoration as is more commonly known is part of the attempt to change the feel of the space by changing more cosmetic elements such as colors, textures, adding plants, furniture, paintings or murals and so on.

Sample of addition to a single family home in Toronto

Check if it Requires a Building Permit

Whatever your needs might be, it's important to know that some of these alterations may require building permit (building department approval). Other don't. In general, any increase in building footprint, or increasing the hazard index of a building, or adding more strain on the existing structural or fire/life safety systems, privacy, overhangs, change of building character the might be incompatible with the neighborhood's pattern, may all require different approvals sometime from different authorities.

Thank you very much for reading my blog.

If you're thinking to build or renovate, don't start before reading our FREE report called the Rapid Project Planning Package or PPP. It covers all key questions or "Should Ask Questions" SAQ about your anticipated project. No obligation. CLICK HERE TO DOWNLOAD NOW!

Here is what you get:

  • ​Road map that shows you the design and construction process from start to finish
  • ​Our hand-picked list of experts who can help you at each stage of the process
  • ​Costs guide worksheet that gives you a ballpark cost estimate for your project
  • ​Project specific checklists for key tasks
  • ​One-on-one FREE 30-minute consultation with an expert to answer your questions and point you towards the right people and resources
  • ​Monthly email tips and strategies to maximize your success
in our valued clients' words

other Blogs

How Can Architects Combat Loneliness in Multi-Family Building Designs?
July 6, 2024
In the realm of real estate development, the process of assembling a reliable and efficient team ...
Avoiding Team Selection Mistakes in the Development of Residential Projects
March 25, 2024
In the realm of real estate development, the process of assembling a reliable and efficient team ...
Architectural Insights: Disrupting 3 Traditional Beliefs in Development Projects
March 17, 2024
In the dynamic world of land development, architects are not mere creators of spaces; they are catalysts for change, challenging established norms...