Additions to a House
A guide to prepare your building application.
An addition is defined as adding to an existing building. If you plan an addition that requires substantial removal of the existing house, you will require a separate demolition permit.
If you plan to create a separate dwelling unit, please refer to the accessory apartment page.
Project preparation
Before you get started, consult the zoning by-law to ensure your house plans, proposed dimensions and location are permitted under the Town of Oakville's zoning by-laws which regulate the use, shape and location of buildings on properties. Visit our Zoning page or contact us at 905-845-6601 ext 3955.
If you plan to add additional plumbing fixtures you are required to submit a water service calculation form to verify your water service is adequately sized to handle the additional load or if upgrading is required.
If your addition adds a sixth or more bedroom, you will require a Building Code Part 6 ventilation design.
One of these two approvals is required for your project:
Transportation & Engineering Site alteration
A separate site alteration permit is required when digging, excavating or altering the grade in certain geographic zones. Contact Service Oakville at 905-845-6601 or serviceoakville@oakville.ca for more information.
Transportation & Engineering Site plan
A separate site plan permit is required when digging, excavating or altering the grade in certain geographic zones. Contact Service Oakville at 905-845-6601 or serviceoakville@oakville.ca for more information.
Heritage properties are managed to conserve important cultural heritage attributes. If your property is on the town's heritage registry it may require heritage approval. Learn more at on our Heritage Planning page or contact a town Heritage Planner for assistance at 905-845-6601 ext . 3870 or 3875.
If your project includes excavation and your property backs onto green space, a river bed or wetland you will need Conservation Halton approval. Learn more on Conservation Halton's website. Contact Conservation Halton for approval at web@hrca.on.ca or 905-336-1158.
- Trees on your property, your neighbor's property and on the municipal right of way may require tree protection, particularly when heavy equipment and excavation is involved. In certain instances, a separate permit may be required to remove private trees. Visit our Licensed Contractors page to find an arborist.
- Digital copies of drawings and documents are required, scaled to size and flattened. If preparing the documentation is beyond your comfort level or experience, we recommend working with a Building Code (BCIN) qualified designer, architect or engineer.
- Contact Ontario One Call at 1-800-400-2255 before you dig to locate underground utilities and avoid damage during construction.
To add an addition to a house on your property you will need a building permit.
Visit our Building Permits page for details.
Submission material checklist
Prepare the following documents and apply online on our Online Services page.
Select the hyperlinks for example drawings and documents.
- Site plan including zoning statistics
- Architectural plans, floor plans, elevations, building sections, construction notes and details
- Water sizing form (payable at time of application)
- HVAC load calculation and duct design
- Engineered drawings and commitment to general review- (if applicable to your project)
- Precautions during excavations (if applicable to your property)
- Transportation and engineering site plan approval (if applicable to your property)
- Planning services full site plan (if applicable to your property)
- Energy Efficient Design Summary (EEDS)
- OBC Part 6 ventilation design (if applicable to your project)
- Heritage approval (if applicable to your property)
- Conservation approval (payable at time of application)
- Fee (payable at time of application)