Home Additions Hub · Burnaby and Greater Vancouver
Home additions in Burnaby: when an addition becomes a new home.
Most guides to home additions are about design. The thing that actually decides an addition project in British Columbia is a legal threshold, and it catches people late, after the drawings are done and the budget is set.
Last reviewed September 2026
The short answer
An addition in British Columbia is treated as a renovation until it is substantially reconstructed, at which point the Homeowner Protection Act treats it as a new home. BC Housing sets the test in Regulatory Bulletin No. 6: a home qualifies when 25% or less of the original structure above the foundation remains, or when 75% or more of the reconstructed home is new. For an addition, the bulletin puts it in a form you can hold a tape measure to. If the new portion is at least three times the size of the original structure remaining, the home is substantially reconstructed. Crossing that line requires a New Home Registration Form, and with it either a licensed residential builder who has arranged home warranty insurance, or a formal exemption such as an Owner Builder Authorization.
That is the whole hub in one paragraph. What follows is how the test applies to the two additions people actually build, what Burnaby requires on the permit side, and how the work runs while a family is still living in the house.
The four questions that decide it
Work them in order. The first one can end the enquiry on its own, because an addition that creates a unit is judged on a different basis than one that just makes a house bigger.
Does the addition create a new dwelling unit?
Bulletin No. 6 says the first consideration for an addition is whether it creates one or more additional units. If it creates a legal secondary suite, no New Home Registration Form is required. If it creates a duplex or a triplex, a form is required on the new unit the addition created. Only when no new unit appears does the size test below come into play.
Is 75% or more of the finished home new?
BC Housing treats a home as substantially reconstructed when 75% or more of the reconstructed home is new, or when 25% or less of the original structure above the foundation remains. The bulletin puts the addition version plainly: if the new portion is at least three times the size of the original structure remaining, it is substantially reconstructed.
Is the foundation new as well as the storey above?
Scenario 2 covers a lower bar. Where the foundation is new, 50% or more of new above-foundation structure is enough to make the home substantially reconstructed. The bulletin's own worked example is an existing first storey on a new foundation with a new second storey and roof added.
Who makes the final call?
The bulletin states that each case is examined on its own merits and the final determination is made by BC Housing. It also says it does not constitute legal advice. BC Housing runs a Substantial Reconstruction Online Query tool for this, and notes some projects need a secondary assessment. Treat any answer you reach on your own as provisional.
Every figure above is quoted from BC Housing Regulatory Bulletin No. 6 (October 2023), linked in the sources at the foot of this page. The bulletin states that it does not constitute legal advice, and that BC Housing makes the final determination.
What Burnaby requires before anyone frames a wall
What counts as an addition
Any change to a building's footprint or an increase in floor area is considered an addition, in the City of Burnaby's own words. That definition reaches past living space to catch expansions of accessory buildings, garages, awnings, patio covers, decks and hot tubs.
What needs a permit
Burnaby requires a permit for any construction project involving the excavation, erection, enlargement, alteration, removal, fire repair or demolition of any building or structure, including accessory and temporary buildings.
What does not
The City lists minor works as exempt: replacing fixtures, cabinets and flooring, painting the inside of your home, and minor non-structural repairs to the outside. An addition is none of these, because it changes the footprint or the floor area.
Which form, and what rides along with it
Additions to existing homes use Burnaby's Building Permit Application for Additions and Alterations to Existing Residential Buildings. The form declares Addition and Floor Addition as separate scopes, marks an Engineering Pre-Application as required, and states that electrical, plumbing, gas, heating, sprinkler and illuminated sign permits are all separate.
The four sub-guides
Each one takes a part of the problem and works it through with the same sourcing discipline as this page.
Is an addition the right move?
Best for
- A structurally sound house where only the space is wrong
- Lots with zoning headroom left under coverage and setbacks
- Families who want to keep the location, the trees and the neighbours
- Work that adds a unit, since a legal secondary suite avoids the New Home Registration Form
Fails when
- The existing structure would need so much replacement that the project crosses the 75% threshold anyway
- Foundations or framing cannot carry the new load without being rebuilt
- The lot is already at its coverage or permeable surface limit
- The design needs the existing floor levels to move, which rarely stays an addition for long
Verify before acting
- Run BC Housing's Substantial Reconstruction Online Query before the design is finalised
- Confirm the zoning envelope on your specific lot, not on the district minimums
- Get an engineer onto the existing foundation before committing to a second storey
- Ask the City which separate permits your scope will need alongside the building permit
Frequently asked questions
When does a home addition legally become a new home in BC?
A home addition becomes a new home under the Homeowner Protection Act when it is substantially reconstructed. BC Housing Regulatory Bulletin No. 6 sets the test: 25% or less of the original structure above the foundation remains, or 75% or more of the reconstructed home is new. For additions specifically, the bulletin says that if the new portion is at least three times the size of the original structure remaining, the home is substantially reconstructed and requires a New Home Registration Form.
Does a home addition need 2-5-10 warranty insurance in BC?
A home addition needs 2-5-10 warranty insurance only when the project is substantially reconstructed under BC Housing Regulatory Bulletin No. 6. Ordinary renovations do not normally require a New Home Registration Form. Once the substantial reconstruction threshold is crossed, you need either proof that a licensed builder has arranged home warranty insurance for the new home, or a formal exemption such as an Owner Builder Authorization.
Do I need a building permit for an addition in Burnaby?
Yes. The City of Burnaby requires a building permit for any change to a building's footprint or any increase in floor area, which is how the City defines an addition. Burnaby also requires a permit for any excavation, erection, enlargement, alteration, removal, fire repair or demolition of a building or structure. Additions use the City's Building Permit Application for Additions and Alterations to Existing Residential Buildings.
What is the 75% rule for renovations in British Columbia?
The 75% rule is BC Housing's threshold for substantial reconstruction. A home is treated as substantially reconstructed, and therefore as a new home under the Homeowner Protection Act, when 75% or more of the reconstructed home is new. The mirror version of the same test is that 25% or less of the original structure above the foundation remains. Crossing it converts a renovation into a new home for licensing and warranty purposes.
Does adding a second storey trigger new home requirements?
Adding a second storey can trigger new home requirements, and the threshold is lower when the foundation is also new. BC Housing Regulatory Bulletin No. 6, Scenario 2, states that where the foundation is new, 50% or more of new above-foundation structure makes the home substantially reconstructed. The bulletin's worked example is an existing first storey on a new foundation with a new second storey and roof structure added.
Does building an addition that creates a secondary suite require a New Home Registration Form?
No. BC Housing Regulatory Bulletin No. 6 states that if an addition creates a legal secondary suite, a New Home Registration Form is not required. The answer changes if the addition creates a separate unit of a different kind: if the work creates a duplex or a triplex, a New Home Registration Form is required on the new unit the addition created.
How big can a rear addition be on a Burnaby lot?
The size of a rear addition in Burnaby is set by the building envelope in Zoning Bylaw No. 14815 rather than by any stated maximum addition size. In the R1 district the binding limits are lot coverage of 30% on lots over 567 square metres or 40% on lots under it, a minimum permeable surface of 40%, and interior side yard setbacks of 1.2 metres each side. Those three together usually decide the answer before the design does.
Does an addition have to meet current energy code requirements?
New parts of an addition are held to a higher energy standard than altered parts of the existing house. The City of Abbotsford's Building Division bulletin on the BC Energy Code for renovations and additions sets an effective RSI of 3.08 for walls in an addition portion against 2.78 for a renovation, and 8.67 for ceilings below attics against 6.91. Requirements are set per municipality, so confirm the schedule with the city your lot sits in.
Who decides whether my addition counts as substantial reconstruction?
BC Housing decides. Regulatory Bulletin No. 6 states that each case must be examined on its own merits and the final determination will be made by BC Housing. The bulletin also says it does not constitute legal advice. BC Housing publishes a Substantial Reconstruction Online Query tool for an initial assessment, and notes that some projects require a secondary assessment through its Compliance Department.
What separate permits does an addition need besides the building permit?
Burnaby's addition permit application states that separate permits are required for electrical, plumbing, gas, heating installation, sprinkler permits and illuminated signs. The same form marks an Engineering Pre-Application as required, and asks whether a demolition permit or a tree permit is needed. A single building permit does not cover the whole project.
Is an addition or a rebuild the better choice?
An addition keeps the parts of the house that still perform and adds only what is missing, which suits a structurally sound home on a lot with zoning room left. A rebuild wins when the existing structure would need so much replacement that the project crosses BC Housing's 75% threshold anyway, because at that point the work carries new home obligations without delivering a new home's layout, foundation or envelope.
Can I stay in the house during an addition?
Whether a family can stay through an addition depends on which systems get interrupted and for how long. A rear addition that leaves the existing roof, kitchen and bathrooms working can often be lived through. A second-storey addition removes the roof over occupied rooms, so the house is usually vacated until the new structure is weather-tight. Decide this before the schedule is set, because it changes sequencing.
Official sources
- Regulatory Bulletin No. 6: Substantially Reconstructed Homes and the Homeowner Protection Act (Oct 2023). BC Housing.
- Homeowner Protection Act, SBC 1998, c. 31 (definition of a new home). BC Laws.
- Home Improvement Permits. City of Burnaby.
- Building Permit Application: Additions and Alterations to Existing Residential Buildings (rev. 5 May 2025). City of Burnaby.
- Burnaby Zoning Bylaw No. 14815, consolidated text (in force 1 July 2026). City of Burnaby.
- BC Energy Code for Renovations and Additions to Part 9 Buildings (1 May 2023). City of Abbotsford Building Division.
- Residential Builder Licensing and the 2-5-10 Home Warranty. BC Housing.
- Permits and Applications (My Permits Portal). City of Burnaby.