Check the property and the proposed use
Describe the space you want to add and the problem it solves. Identify whether the proposal increases the building footprint, changes its height or converts an existing area. Include the intended room use and its connection to the rest of the home.
Review the municipality’s zoning and permit requirements for the property. Setbacks, height, lot coverage and other applicable rules can affect the proposal. If a variance or another approval is needed, investigate that process before treating a preferred design as buildable.
Gather available surveys, existing plans and information about services and earlier alterations. Mark uncertainties. A property line, underground service or condition at the connection to the existing house should not be assumed from a photograph or a rough measurement.
Investigate the existing building and connections
Have the design team identify the structural and building-service information needed. The investigation may need to address existing foundations, the proposed load path, openings through the current building and the connection between old and new construction. Ask what has been verified and what remains an assumption.
Foundation design must reflect the proposed building, ground conditions and applicable requirements. There is no single Ontario frost-depth figure that can safely be substituted for that design work. Nor does every project have the same foundation solution or cost driver.
Coordinate enclosure, drainage, heating, ventilation and other service connections with the room design. Confirm the professionals and trades responsible for each part. Interior finish selection should follow the required space and assembly decisions rather than conceal unresolved technical interfaces.
Budget the whole addition and its effect on the home
| Budget area | Items to identify |
|---|---|
| Investigation and design | Information gathering, design work and required submissions. |
| Construction | Site preparation, structure, enclosure and connections. |
| Services and finishes | Agreed installations, retained areas and making good. |
| Project arrangements | Access, protection, temporary facilities and household disruption. |
| Unresolved work | Specific risks or allowances requiring further information. |
Use quotations based on the same developed proposal. A fixed contingency percentage does not establish that unknown ground or structural conditions are covered. Keep exclusions and provisional amounts visible.
Agree how the existing home will be protected and used during construction, and how changes will be approved. Confirm the exact interior finishing work requested from D&D and the interfaces with the addition’s designer and constructor. Do not assume structural design, a complete addition contract or every trade is included with a finish-service enquiry.
Key takeaways
- Test zoning and project feasibility before committing to a preferred design.
- Investigate connections to the existing building.
- Price design, construction, services and disruption as a complete scope.
Sources and further reading
Include a preferred date and time
Plan your renovation
Select the room or finish you want to change and describe how you use the space.
Prefer to send the details first? Request a quote or call (519) 501-5003.