Add to a house
Addition, vestibule, sunroom, attached garage, suite or added storey with rigorous integration into the existing building.
Project types
- Rear addition
- Side addition
- Added storey
- Vestibule
- Four-season sunroom
- Attached garage
- Intergenerational suite
Scope to coordinate
- Survey of existing structure, foundation, levels and systems
- Electrical, heating, ventilation and plumbing capacity
- Siting, parking, trees, easements and stormwater
- Temporary shoring and load transfer
- Old-new roof, air barrier, insulation and flashing junction
- Occupant protection from water, cold, noise, dust and hazardous materials
- System balancing and seasonal movement follow-up
Critical controls
- Do not assume a wall is non-load-bearing.
- Design and mock up the old-new junction before opening.
- Prepare weather protection before opening the enclosure.
- Inspect the junction after rain, thaw and first heating season.
Potential participants
- Municipality
- Surveyor
- Architect/technologist
- Structural and sometimes geotechnical engineer
- System and hazardous-material specialists
Common method
Six phases with project-specific application
1Feasibility and diagnosis
Confirm constraints before committing to the project.
Application to this project: Existing-building diagnosis and feasibility
Work and decisions
- Define the need, future use, budget limits and performance target.
- Survey the existing building or site, services, water, access and known risks.
- Check zoning, permits, easements, environment and required professionals.
- Separate confirmed facts, assumptions and unknowns in a dated register.
Hold points and controls
- No irreversible purchase or contract before confirming major constraints.
- A map, nearby borehole or verbal opinion does not replace project-specific verification.
Records to keep
- Baseline surveys and photos
- Authority responses
- Risk and assumption register
2Design, coordination and budget
Turn needs into measurable coordinated scope.
Application to this project: Siting, junctions and system capacity
Work and decisions
- Coordinate architecture, structure, enclosure, plumbing, electrical, ventilation and drainage.
- Select products and quality levels with acceptable alternatives.
- Build a trade budget including fees, permits, tax, contingency and financing.
- Create a schedule with dependencies, procurement and inspections.
Hold points and controls
- Review drawings and interfaces before tender.
- Do not compare prices without common scope and explicit exclusions.
Records to keep
- Coordinated drawings and details
- Specifications and inclusion-exclusion matrix
- Baseline budget and schedule
3Permits, contracts and mobilization
Clearly assign approvals, responsibilities and protections.
Application to this project: Permits, contracts, relocation and temporary protection
Work and decisions
- Submit required documents and track permit conditions.
- Verify licences, insurance, references, subcontractors and capacity.
- Define payments, changes, holdbacks, warranties and closeout deliverables.
- Plan safety, occupant, neighbour, water, dust and access protection.
Hold points and controls
- No start without applicable approvals and issued-for-construction documents.
- No verbal change without written scope, cost and time.
Records to keep
- Permits and conditions
- Contract and appendices
- Quality, safety and inspection plan
4Concealed work and hold points
Control elements that are difficult to correct after concealment.
Application to this project: Shoring, foundations, structure and concealed connections
Work and decisions
- Inspect soil, excavation, reinforcement, anchors, drainage and conduits before concrete or backfill.
- Verify load paths, connections, bracing and temporary shoring.
- Coordinate rough systems and penetrations before insulation or drywall.
- Photograph each concealed element with location and scale.
Hold points and controls
- No concealment without planned inspection and resolved deviations.
- Stop immediately for unexpected water, soil, bearing or material.
Records to keep
- Inspection and test reports
- Pre-concealment photos
- As-built record of concealed work
5Enclosure, systems and commissioning
Make the building watertight, functional, balanced and testable.
Application to this project: Enclosure, systems, testing and finishes
Work and decisions
- Verify continuity of water, air, insulation and flashing layers.
- Test plumbing, drainage, electrical, heating, ventilation, controls and safety.
- Complete balancing, settings, leakage tests and corrections.
- Protect sensitive materials until temperature and humidity are suitable.
Hold points and controls
- Approve mock-ups and critical details before repetition.
- No equipment acceptance without commissioning and service access.
Records to keep
- Commissioning reports
- Product data and settings
- Equipment and serial number list
6Closeout, warranties and follow-up
Deliver documented maintainable work with seasonal follow-up.
Application to this project: Closeout and seasonal old-new junction follow-up
Work and decisions
- Inspect by space and system with photos, owner and due date.
- Obtain closed permits, as-builts, manuals, warranties and training.
- Reconcile budget, changes, credits, holdbacks and final balance.
- Plan maintenance, warranty review and inspection after rain, freeze or heating season.
Hold points and controls
- No acceptance without dated deficiencies and critical deliverables.
- Keep an exported copy of the file outside the browser.
Records to keep
- Deficiency list
- Closeout file
- Maintenance and warranty schedule
Related tools
Always confirm applicable permits, professions, insurance and code editions.