Ground floor and up
Rear & side additions
Kitchens, family rooms and bedrooms added at the back or side, on new foundations tied to the old.
- Foundation & footings
- Tie-in to existing structure
- Roof junctions
- Matching or contrasting exterior
Home Additions
More house, tied into the one you have.
Rear, side and second-storey additions and new duplex units, with the beams, columns and mechanicals worked out before the first cut. The London duplex on our project list added a unit to an existing house with new structure and HVAC.
- Building
designs - 200+
- Years of
practice - 10
- Trusted
partners - 20+
- Recent project
- London · duplex unit
- Drawn & stamped
- In-house, one P.Eng and BCIN team
- Service area
- GTA, within 90 minutes of Richmond Hill
- First consultation
- Free, by phone or on site
What’s included
Scope: what we take on, and what each part includes.
An addition is judged where it meets the old house: the beam that opens the wall, the roof that joins the existing one, the ducts that have to reach the new rooms. We design those joints first.
A second home in the house
New duplex units
Additions that create a separate unit, with the entrance, separations and services a second dwelling needs.
- Unit layout & entrance
- Fire separation
- Second kitchen & bath
- Separate metering options
Opening the old wall
Beams & columns
The structure that lets the new space join the old: beams, posts and footings designed and stamped by our P.Eng.
- Beam & column design
- Foundation design
- Second-storey load checks
- Temporary shoring
Reaching the new rooms
Mechanical tie-ins
Heating, cooling, plumbing and electrical extended or upgraded so the addition is served as well as the original house.
- Heat-loss check for the larger house
- Duct extensions or a second system
- Plumbing & DWV extensions
- Panel capacity & circuits
The package
When you need it, and what you get.
Find your situation below. If it’s there, this is the service, and the card underneath is everything you get from our one office.
You need this when
05 common situations
- Outgrown the houseBut not the neighbourhood
- More room downstairsMain-floor bedroom or a bigger kitchen
- Add a rental unitWhere the lot has room for it
- Go up a storeyCan the foundation take it?
- One teamDrawings, permit and build
- Not sure it applies?Tell us about it on a free call and we’ll say whether this is the right service.
What you get
07
items in your package, all from one P.Eng and BCIN team.
Drawn & stamped in-house
- Site visitThe house measured and drawn
- Zoning checkSetbacks, coverage and height
- Permit drawingsArchitectural, structural, HVAC, electrical
- Grading planWhere the city requires one
- Building permitFiled and followed to issue
- ConstructionOur crew, foundation to finishes
- Inspections & close-outThe permit closed when it’s done
How it runs
Process: 4 steps from first call to sign-off.
Four steps, with the slowest one, the tie-in to the house you are living in, planned around you.
Site visit & zoning
We measure the house and lot, check what the by-law allows and look at the foundation and framing the addition will connect to.
Design & permit
Plans and elevations, structure, HVAC and electrical from one office, filed with the city and answered at no extra charge.
Build
Excavation, foundation, framing and the opening into the existing house, then rough-ins, exterior and finishes, inspected at each stage.
Close out
Final inspection, permit closed, the house handed back as one building.
- Property address and a survey, if you have one
- What you want to add and where
- Photos of the side of the house and the yard where it would go
- Any existing drawings or previous permits
- Whether the addition is for you or for a rental unit
Case files
Our Projects: real permits, real builds, real value added.
Open any file for the scope, the disciplines involved, what we delivered and what the owner came away with.
- Files
- 08
- Municipalities
- 07
A compact two-storey suite in a Toronto backyard. Architectural and structural drawings, zoning review and a framing package that makes every square foot count.
- Location
- Toronto
- Area
- 700 sq ft
- Sector
- Residential
- Disciplines
- Architectural · Structural
Delivered
- Architectural drawings
- Structural framing design
- Zoning review
- Building permit application
New living space on a lot the owners already had.
Start a project like this
Structural walls came out and rooms were added to open the plan. Beam and column design, permit drawings and renovation coordination through to final inspection.
- Location
- Richmond Hill
- Area
- 2,700 sq ft
- Sector
- Residential
- Disciplines
- Structural · Architectural
Delivered
- Load-bearing wall removal
- Beam & column design
- Permit drawings
- Renovation coordination
An open layout where the load-bearing walls used to be.
Start a project like this
A code-compliant second unit with its own entrance, fire separations between the units, HVAC design and the full permit package.
- Location
- Vaughan
- Area
- 1,100 sq ft
- Sector
- Residential
- Disciplines
- Architectural · Mechanical · Fire safety
Delivered
- Separate entrance
- Fire separations
- HVAC design
- Full permit package
A legal second unit that brings in rent and adds property value.
Start a project like this
A new build taken from the client’s sketch to occupancy, with the architectural, structural and mechanical design done by one team.
- Location
- Haldimand County
- Area
- 1,750 sq ft
- Sector
- Residential
- Disciplines
- Architectural · Structural · Mechanical
Delivered
- Architectural design
- Structural design
- Mechanical design
- Permit drawings
Built to the client’s own plan, with one team answering for every discipline.
Start a project like this
A two-storey garden suite laid out to get the most usable space from the footprint, designed and permitted as a rentable unit.
- Location
- Richmond Hill
- Area
- 1,250 sq ft
- Sector
- Residential
- Disciplines
- Architectural · Structural
Delivered
- Layout planning
- Architectural drawings
- Structural design
- Permit application
Rental income and a higher property value.
Start a project like this
A dental office converted into a supermarket. Interior renovation, a new plumbing system and fire separations upgraded to the Ontario Fire Code.
- Location
- Kitchener
- Area
- Dental → grocery
- Sector
- Commercial
- Disciplines
- Architectural · Plumbing · Fire safety
Delivered
- Change-of-use permit
- Interior renovation drawings
- New plumbing design
- Upgraded fire separations
A dental office reopened as a supermarket, compliant with the Ontario Fire Code.
Start a project like this
A custom covered porch that turns the front of the house into usable outdoor space. Addition design and structural drawings for the permit.
- Location
- London
- Area
- 570 sq ft
- Sector
- Residential
- Disciplines
- Architectural · Structural
Delivered
- Addition design
- Structural drawings
- Permit application
More usable outdoor space and added home value.
Start a project like this
Site grading to manage drainage and prepare the land for a new driveway, drawn as a grading plan for the site alteration permit.
- Location
- Guelph
- Area
- 11,700 sq ft
- Sector
- Site
- Disciplines
- Site engineering
Delivered
- Grading plan
- Drainage design
- Driveway extension layout
- Site alteration permit
Drainage handled and the land ready for a new driveway.
Start a project like thisPhoto plates
Project Gallery: from the framing to the finished room.
Additions, basements, kitchens, new builds and commercial fit-outs. Drag a row to scrub through it, or open any photo full size.Tap any photo to see it full size.
21 platesResidential, commercial & new build
The drawing set
Drawing Samples: sheets from real permit sets.
Framing schedules, wall assemblies, dimensions and a city review stamp, as issued. Client title blocks are trimmed off to protect the people we drew them for.
- Sector
- Residential
- Discipline
- Architectural · Structural
- Location
- London, ON
- Scale
- —
Drawing set
Sheets in this set
Sheet title
Existing basement plan
The existing house recorded before any design: beams, joists and bearing walls.
Drawing no.
2 of 5
Service area
Where We Work: within 90 minutes of Richmond Hill.
From the office we cover the whole GTA, north to Barrie and Orillia, east to Peterborough and Cobourg, west to Kitchener and Brantford, and down through Niagara.
Our office
Service area
Completed project
Drive time, off-peak
Municipalities we serve
46 across 8 regions
York Region
- Richmond Hill (completed project)Office
- Vaughan (completed project)
- Markham (completed project)
- Aurora
- Newmarket
- King
- Whitchurch-Stouffville
- East Gwillimbury
- Georgina
Toronto & Peel
- Toronto (completed project)
- Mississauga
- Brampton
- Caledon
Halton
- Oakville
- Burlington
- Milton
- Halton Hills
Durham
- Pickering
- Ajax
- Whitby
- Oshawa
- Clarington
- Uxbridge
- Scugog
Simcoe & Dufferin
- Barrie (completed project)
- Innisfil
- Bradford
- New Tecumseth
- Orillia
- Wasaga Beach
- Collingwood
- Orangeville
Waterloo, Wellington & Brant
Hamilton, Niagara & Haldimand
- Hamilton
- Grimsby
- St. Catharines
- Niagara Falls
- Haldimand County (completed project)
Kawarthas & Northumberland
- Peterborough
- Kawartha Lakes
- Port Hope
- Cobourg
Past the 90-minute line
We've also completed projects in London and Strathroy. Farther out than that? Call (416) 990-9179 and ask.
Permits filed with municipalities including
Before you call
FAQ: home additions, answered.
Anything we haven’t answered here, we’ll answer on a call. The first consultation is free.
(416) 990-9179Yes, always. We check the zoning first, because that decides how big the addition can be, then draw the addition and file the permit.
Building out needs a new foundation and leaves the existing structure alone. Building up skips the new foundation but usually means reinforcing the structure underneath. On a tight lot the setbacks may leave room for only one of the two. We compare both at the site visit, once the lot and the structure are measured.
The foundation, the walls and beams that will carry the new floor, and the roof that comes off to make room for it. The existing ceiling joists were sized to carry a ceiling, so a second storey usually needs a new floor structure as well. Some houses then carry it on new posts and beams; others need part of the foundation reinforced first. Our P.Eng settles which at the site visit.
If you want it to. Matching roof pitch, cladding and window proportions is design work we do routinely. Some owners prefer a contrasting addition. Either way the junction with the old roof and walls is detailed so it does not leak.
The approvals come first: the zoning check and drawings, any minor variance, then the permit review. Construction follows, and opening the old house into the new rooms takes longest because you are living there. We give you a schedule with the quote and update it as the city responds.
For a rear or side addition, usually yes: the foundation and framing go up outside the existing walls, and the old wall is opened late, with temporary shoring carrying the load while the new beam goes in. A second storey is different, because the roof comes off, so we plan with you whether to stay through that stage.
Foundations can be poured in cold weather with the right protection, and framing continues through winter. Excavation and exterior finishes are easier in other seasons. We plan the schedule around it.
Then it usually goes to the Committee of Adjustment, and we make the variance drawings and the permit set from one design. The hearing and the plans examiner see the same addition, and a change the Committee asks for goes onto both sets.
Searched & answered
People Also Ask: what the GTA searches about home additions.
Short answers to the home additions questions people search most, and the broader topics they lead to.
Not covered here? Book a free consultationSize, storeys, how much of the existing house is opened and the finishes set it, so a figure given before there is a design means little. Foundation and structure are the fixed part and finishes the variable one, and a minor variance or a new heating system adds its own line. Fine Engineering itemizes the addition after the site visit.
It depends on what the addition adds: a bedroom, a bigger kitchen or a rental unit. The first two let the owner stay on a lot they already own, and a rental unit can also bring in income. Fine Engineering’s Director is a Broker of Record and can say what the new space may be worth at resale before the owner spends.
Once a complete application is in, Ontario’s Building Code gives the municipality 10 business days to issue a house permit or refuse it with reasons. Larger and more complex buildings get a longer period. The count only starts when nothing is missing, so an absent sheet or an unresolved zoning issue holds it back. Fine Engineering checks zoning and code before anything is submitted.
The application form, the drawings the Building Code calls for, and every other approval the project depends on. Zoning counts as applicable law, so a needed minor variance has to be granted before the permit can be issued, and a lot in a conservation authority’s regulated area may need that authority’s permit first. Fine Engineering assembles the whole package, with the designer’s registration details on the drawings.
Most often because the plans do not show that the work meets the Building Code or applicable law, such as the zoning by-law. A permit is also withheld when the law requires an engineer’s or architect’s design and the drawings lack one, or when the builder of a new home is unlicensed. The refusal must state its reasons, and Fine Engineering revises the set to answer each one.
Stop work and start on the drawings. A stop-work order usually means construction began without a permit or departed from the approved plans. Getting out of it takes a permit application that shows what was built and what is proposed, then whatever inspections the city asks for. Fine Engineering prepares those drawings and replies to the city’s letters.
Good to know
Home addition permits and zoning in Ontario
Ontario’s Citizen’s Guide to Land Use Planning says you must obtain a building permit before you add to a building. A building permit can only be issued for work that complies with the Building Code and the applicable laws it lists, and municipal zoning counts as applicable law. If an addition needs a zoning change or a minor variance from the zoning by-law, the permit is not issued until that approval has been obtained.
Since November 21, 2025, Ontario has treated a by-law’s minimum setbacks as 90 per cent of the stated distance on urban residential land, outside the Greenbelt and some prescribed areas. A shortfall beyond that is where a minor variance usually comes in, and we confirm how the municipality applies the rule before drawing. The Committee of Adjustment then decides it on the Planning Act’s tests.
When an addition needs an engineer’s stamp
Ontario’s Building Code Act holds back the permit when the Professional Engineers Act requires an engineer’s design and the work was not designed by one. On an addition, that comes up when a beam or framing goes beyond the Code’s span tables, which a long opening into the old house can do.
Our P.Eng designs and stamps those parts, and our drawings also show how the new work joins the old house. When the site has a question, the same office answers it against those drawings.
Heating and cooling a home addition
The 2024 Building Code does not say an addition on its own triggers a new heat-load calculation, but a bigger house has a bigger load, so we run the heat loss for the whole house as it will be.
That number decides whether the existing ducts can be extended or the addition needs a system of its own, and whether the furnace and air conditioner have the capacity. We check the panel separately, with an electrical load calculation, and settle both before the walls are framed, while a duct route or a second system is still easy to place.
Adding a rental unit with a home addition
Ontario’s Planning Act does not let a zoning by-law prohibit up to three residential units on a serviced urban residential lot. That means three units in a detached, semi-detached or rowhouse, or two in the house plus one in a building ancillary to it. An addition beside or above the house is one way to make room for the second or third.
Under O. Reg. 299/19, anyone may live in an additional residential unit, whether or not they are related to the people in the main unit and whether or not anyone living there owns the lot. The unit still needs fire separation and the exits, kitchen and bath the Building Code asks of a dwelling unit, and we design those with the addition.
Contact us
Zoning checked. Beam sized. Room to grow.
Send us the address and what you want to add and we’ll tell you what fits, on a free first call.
First consultation free(416) 990-9179