Eight stages, roughly nine to fourteen months end to end, and most of the delay sits in two of them. Knowing which two changes how you plan.
One: planning and budget
Start with what the addition is for, specifically. A bedroom, a bigger kitchen, a first-floor primary suite, a home office with a door. The answer determines everything downstream.
Then set a budget with a shape: structure, mechanical, finishes, contingency. A single number cannot tell you which of your wishes are expensive, and that is the only thing a budget is for at this stage.
Two: design and drawings
An architect or designer produces the plans. This takes four to ten weeks depending on how settled you are and how many rounds it takes.
Have the builder in the room for at least one of those rounds. A design priced for the first time after it is finished is the most common reason a project restarts.
One conversation between the builder and the drawings, early, saves more money than any negotiation later.
Three: permits and approvals
This is the first of the two stages that eat time. Depending on the village, review takes four to twelve weeks, and longer where zoning relief, a variance or a design review board is involved.
Nothing visible happens during it, which is why it feels longer than it is. Submitting a complete set first time is the single biggest lever on this stage.
Four: choosing the builder
If the builder was involved during design, this is a formality. If not, allow three to four weeks to get comparable bids, and insist on comparable scopes or the bids mean nothing.
Contract signed, draw schedule agreed with your lender if you are financing, and a start date that reflects the trades' actual availability rather than the earliest anyone could imagine.
Five: site preparation
Utility locates, a dumpster, site protection and whatever temporary arrangements the household needs. If the addition touches the kitchen, this is when you set up the temporary one.
Protect what is staying. Floors, stair treads, doorways and the route the trades will use a hundred times a week.
Six: construction
Excavation and foundation, framing, roof, windows and exterior. Then rough mechanical, inspection, insulation, drywall, and finishes.
This is the second stage that eats time, and the delays here are almost always decisions rather than labour. Tile not chosen, a fixture on back order, a change made at drywall. Keep a decision calendar and stay ahead of it.
- Foundation and framing: four to eight weeks.
- Rough mechanical and inspection: two to four weeks.
- Insulation, drywall and finishes: six to twelve weeks.
- Exterior match and final grade: runs alongside, finishes last.
Seven: inspections and approval
Footing, framing, rough electrical, rough plumbing, insulation and final. Each one has to pass before the next stage proceeds, which is why sequencing matters more than speed.
The final inspection produces the certificate of occupancy. Until it exists, the addition is legally not part of the house.
Eight: quality review and move in
Walk the space with the builder and write down everything. Then walk it again a week later, because the second list is always different from the first.
Hold the final payment until the final quality review is actually complete. That is not adversarial, it is simply how the last five per cent of a project gets finished.
