New Construction Windows in Ontario: Whole-House Packages, Window Schedules, Rough Openings, ICF Installation, Flashing, Condensation, Leaks and Warranties

Windows & DoorsNew Builds & Installation

Windows for a New House: The Package, the Schedule, the Rough Openings, the ICF Buck, and the Flashing That Decides Whether the Wall Stays Dry

What I do on every house I build, written down for the owner-builder, the person checking their builder, and the framer on his first ICF job.

On a new build the windows are a package: one schedule, one supplier, one delivery, a crew already on site. The money goes wrong at the schedule (a size nobody checked), at the rough openings (framed to the wrong sheet), and at the flashing (the step somebody skipped because the trim covers it). These pages are those three things, plus the ICF opening that most crews have never done, and the pages on condensation, leaks and warranties that every house needs eventually.

Window schedule takeoff, $249 Package costs Windows in ICF

The numbers

$950per standard casement, new construction, installed
$28,000typical 2,400 sq ft package, mid-grade vinyl
+1/2 in.typical rough opening over the unit, per the maker’s sheet
6 to 10weeks lead time; order at foundation

The guides

New-home window and door cost

What a whole-house package runs by grade, supply vs. install, and a real 2,400 sq ft package priced.

How to read a window schedule

IDs, sizes, types, rough openings, handing, glass and egress notes, and the errors in most sets.

Windows in ICF walls

Bucks, anchoring, the wide jamb, flashing to foam, and the three mistakes framers make on their first ICF house.

Rough opening sizes

How much bigger than the window, why every maker differs, doors, ICF bucks, and the half inch that decides.

Window installation checklist

Flashing order, sill pans, foam, sealant, what to look at on install day, and the faults of year three.

Window condensation

Inside the room, between the panes, or on the outside: three different problems and the humidity chart.

Window leaks and water damage

Where the water really comes in, the stain patterns, the hose test, and when the wall has to open.

Warranties explained

Manufacturer vs. installer, lifetime and prorated, labour, transfer on sale, and the exclusions.

The order on a build

  1. Check the schedule against the plan before anyone prices it: count, sizes, egress, tempered, handing, headers. How.
  2. Pick the maker, get their rough opening sheet, write the R.O.s on the plan. Rough openings.
  3. Order at foundation with the glass specified by wall and the colour decided. What it costs.
  4. Frame or buck to the R.O. sheet, not the nominal size. In ICF, check the bucks after the pour. ICF openings.
  5. Install in the sequence, pan, window, jamb tape, head tape, wrap over, foam, sealant, and look before the trim goes on. The checklist.
  6. Register the warranties and keep the serial numbers. Why.

The calculators

Window replacement cost calculator

Every opening on its own line by type and size, vinyl or fibreglass, double or triple, retrofit, full-frame or new construction, doors on the same sheet, HST on the bottom. Writes the schedule for three quotes.

Exterior door cost calculator

Steel or fibreglass entry doors with sidelights, transoms, glass and locks; sliding, French and 8-ft patio doors; the wall, the floor and the finishing. The whole system, installed.

Have quotes or plans in hand? Let a builder read them first

For $99, I read your window and door quotes against your openings and send back what is missing, where the price is out of line with October 2026 Ontario rates, and the questions to ask before you sign. For a new build, $249 turns your plans into a checked window and door schedule three manufacturers can quote the same way. The quote review and the schedule takeoff.

Window and door quote review, $99 Window schedule takeoff, $249 Check the quotes yourself first

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