Do I need a building permit for a home addition?

Yes. Every addition needs a building permit, and many also need zoning review. We prepare the drawings and manage the application for you.

Can we stay in the house during an addition?

In most rear and side additions, yes. We seal off the work area and plan the tie-in to keep disruption short. Second-storey additions usually require moving out for part of the build.

How long does a typical addition take?

Construction is commonly three to five months once permits are issued. Your quote includes a phase-by-phase schedule for your specific project.

Will the addition match my existing house?

It can match exactly or contrast deliberately. We source brick, siding and roofing to suit, and show you the options before ordering.

Can you build an addition in winter?

Framing and interior work continue through winter. Excavation and foundations are best scheduled outside deep frost, so we plan start dates around the season.

Who handles the engineering?

We coordinate a licensed structural engineer, and the stamped drawings form part of your permit package.

Finished single-storey rear addition with floor-to-ceiling sliding doors on a brick bungalow at dusk

Home Additions

More room, without moving — planned around how you actually live.

Get a Free Quote

A home addition is the most reliable way to gain real square footage on a lot you already love. DWB Construction handles the whole path: feasibility, design and permit drawings, structural engineering, the build itself and the final inspection.

Additions suit families who have outgrown a bungalow or a semi, households wanting a main-floor primary suite, and anyone who needs a kitchen and family room that open properly to the yard.

What's included

Everything, itemised

Your quote lists each of these as its own line, so nothing is assumed.

Design & approvals

Measured survey of the existing home
Concept layouts and design drawings
Permit drawings and zoning review
Development and building permit applications
Minor variance support where zoning requires it
Structural engineering and stamped drawings

Structure & shell

Excavation, footings and foundation walls
Waterproofing and weeping tile
Floor, wall and roof framing
Roofing, flashing and eavestrough
Windows and exterior doors
Exterior cladding matched or contrasted to the existing house

Services & close-in

Electrical rough-in and finish
Plumbing rough-in and finish
HVAC extension or new equipment sizing
Insulation and air sealing to the provincial building code
Inspections booked and attended at every stage

Finishing

Drywall and taping
Flooring tied into existing floors
Cabinetry, trim and doors
Painting inside and out
Site restoration, grading and sod

Options

Choose the right approach

Rear addition

The classic extension of the main floor into the yard, usually for a larger kitchen and family room with wide glazing.

Best for: Bungalows and two-storeys with usable rear yard depth

Side addition

Builds into a side yard to add a room, mudroom or wider kitchen without losing the back garden.

Best for: Corner lots and wider properties

Second-storey addition

Adds a full floor over the existing footprint — the most space per dollar of lot, with careful structural checks.

Best for: Bungalows on smaller lots

Indicative costs

Guide price ranges

Single-storey rear addition: To be confirmed
Side addition: To be confirmed
Second-storey addition: To be confirmed

Guide prices vary with size, specification and site conditions — your itemised quote will confirm the exact figure before any work begins.

Typical timeline

Phase by phase

1Design, drawings & engineering3–6 weeks
2Permit reviewVaries by municipality
3Excavation, footings & foundation2–3 weeks
4Framing, roofing & close-in3–5 weeks
5Rough-ins & inspections2–3 weeks
6Insulation, drywall & finishes4–6 weeks
7Deficiency walkthrough & handover1 week

Permits: Typically several weeks to a few months, depending on the municipality and whether a minor variance is required

Process

How a home additions project runs

01
Enquiry
Tell us what you have in mind and roughly when you'd like to start.
02
Site visit & measure
We measure, check the foundation and lot setbacks, and talk through layout, light and budget.
03
Itemised quote
A line-by-line price with exclusions spelled out, so you can compare like for like.
04
Build & manage
One project lead runs trades, inspections and the schedule, with a weekly update you can rely on.
05
Walkthrough & aftercare
We walk the finished space with you, close out every deficiency and stay on call under warranty.