Lynden Exterior Building New in Aldergrove? The Window Install Only Happens Once
If you're building a new home in Aldergrove, the window installation is one of the few parts of the job where there's no second chance without tearing into the wall. Once the siding or stucco goes on, the flashing behind it is buried. If it was done wrong, you won't know until there's a stain on a ceiling or rot in a sill years later. We install windows during the framing stage, before the weather-resistive barrier and cladding are closed up, which is the only point where the job can be done completely right.
We work out of Lynden, just south of the border, and Aldergrove is one of the closer Canadian communities to us — close enough that we're on new-build sites there regularly, working alongside the framers, the house-wrap crew, and the builder's schedule rather than showing up as an outside trade nobody's coordinated with.
Why New-Construction Windows Aren't Just "Bigger Replacement Jobs"
Replacement window work fits a new unit into an existing, already-flashed opening — the goal is a clean fit and a good seal at the frame. New-construction work is different: there is no existing flashing. We're building the entire water-management system around the window from scratch, integrating it into the wall assembly before anything covers it up.
- Replacement: works within existing flashing and finish surfaces; speed and fit matter most.
- New construction: installer controls the full flashing sequence — sill pan, jamb flashing, housewrap integration, head flashing — before cladding closes it in.
- Consequence of getting it wrong: a replacement mistake is usually visible and fixable at the interior trim. A new-construction mistake is often hidden behind siding for years.
Because there's no do-over once the exterior is finished, we treat new-construction window installs as a sequencing job first and a product-installation job second. The window itself matters, but the order of operations around it matters more.
What Aldergrove's Climate Actually Asks of a New Window System
This part of the Pacific Northwest doesn't get extreme weather, but it gets a lot of the weather that quietly wears down a wall assembly over years rather than all at once. Three things in particular shape how we detail a new-construction install here:
Salt-laden marine air. Even away from the immediate coastline, air moving in off the Salish Sea carries salt that accelerates corrosion on exposed fasteners, hardware, and unprotected metal flashing. We spec corrosion-resistant fasteners and flashing metals rather than whatever's cheapest at the yard.
Driving rain. Wind-driven rain doesn't just fall on a window, it pushes sideways against it, which is exactly the condition a sill pan and proper shingle-lap flashing are designed to handle. A install that only accounts for water falling straight down will leak the first time a real windstorm comes through off the strait.
A long moss and wet season. Extended damp periods mean any trapped moisture behind cladding has months, not days, to do damage before a dry stretch lets things breathe again. That's why drainage paths behind the window and cladding need to actually work, not just look sealed on installation day.
None of this is exotic engineering — it's standard PNW building science. But it only works if every layer is actually installed in the right order, which is where a lot of new-construction window problems actually start.
The Flashing Sequence That Actually Keeps Water Out
Sill Pan First
Before the window ever goes in, the rough opening gets a sloped sill pan — a dedicated flashing membrane at the bottom of the opening that sheds any water that gets past the window itself, directing it back outside instead of into the framing. This is the single most important step in the whole sequence and the one most often skipped or done poorly on production builds.
Shingle-Lap Housewrap Integration
The window flange gets integrated into the weather-resistive barrier in a "shingle-lap" order — meaning each layer overlaps the one below it, the same way roof shingles work, so water is always directed down and out rather than finding a horizontal seam to work into. Get this order backwards and you've built a funnel instead of a barrier.
Head Flashing and Drip Caps
Above the window, a head flashing with a drip cap kicks water away from the top of the frame before it can run down the face of the window or behind the barrier. This is a small, inexpensive detail that does a disproportionate amount of the work during a driving rain event.
Choosing the Right Window for a Canadian New-Build
Because Aldergrove is in British Columbia, the windows going into that home need to meet Canadian code requirements, not just U.S. ones. In practice, most quality window lines today are certified to the harmonized North American Fenestration Standard, but it's worth confirming the specific rating and documentation match what your local building department and energy code (BC's step-code framework pushes new homes toward tighter, better-performing envelopes) will ask for. We sort this out with your builder before ordering, not after the windows arrive.
Frame material is the other big decision on a new build, since you're choosing it once for the whole house:
| Frame Type | Moisture & Corrosion Behavior | Maintenance | Typical Fit |
|---|---|---|---|
| Vinyl | Won't rot or corrode; performs well in wet marine air | Low — no painting or sealing | Most cost-conscious new builds |
| Fiberglass | Very stable, minimal expansion/contraction, excellent in driving-rain exposures | Low | Higher-performance or larger openings |
| Wood-clad | Good performance if the exterior cladding and flashing are flawless; any breach exposes wood to a long wet season | Higher — depends on maintaining the seal | Homes prioritizing interior wood appearance |
We don't push one brand or material as universally "best." We'll tell you honestly where each option's trade-offs land for your specific design, sun exposure, and budget, and we'll flag any product we think is a poor match for this climate rather than install it anyway and let you find out later.
Our Process, Rough Opening to Final Seal
- Verify rough openings against window schedule and check framing is square, plumb, and properly sized before anything else happens.
- Install sloped sill pan flashing at each opening.
- Set the window, shim and level it, and fasten per manufacturer spec — under- or over-driven fasteners both cause problems later.
- Integrate jamb and head flashing into the housewrap in correct shingle-lap order.
- Apply interior air-sealing (low-expansion foam or backer rod and sealant) around the frame — this is an air-seal step, not a water-management step, and the two shouldn't be confused.
- Photograph and log flashing details at each opening before cladding covers them, so there's a record of what's behind the finished wall.
- Final walk-through with the builder or homeowner before siding crews close things in.
Coordinating With Your Builder's Schedule
On new-construction jobs we typically work as part of the build team, scheduled by and coordinated with the project's general contractor — we're not an independent trade showing up on our own timeline. That matters more on a cross-border job like an Aldergrove build than it would on a same-city job, because scheduling has to account for material lead times, crossing logistics, and lining up with whoever is holding inspections for the project. We handle our end of that coordination directly with your builder so it's one less thing you have to manage.
Being a short drive from Aldergrove rather than a distant out-of-town crew also means we're not trying to cram your install into a single rushed trip — if flashing needs to cure, or a delivery slips a day, we can be back on site without the whole schedule falling apart.
What New-Construction Window Installation Costs
Every new build is different, but the main cost drivers on a whole-house window install are consistent enough to plan around:
| Cost Factor | Why It Matters |
|---|---|
| Number and size of openings | More openings and larger units mean more flashing detail work and labor hours, not just more glass |
| Frame material and performance rating | Higher energy-code performance windows generally cost more per unit than baseline options |
| Wall assembly complexity | Rainscreen or advanced wall assemblies take longer to integrate correctly than a basic wall |
| Access and building height | Second-story and hard-to-reach openings add setup time and equipment |
| Timing with other trades | Well-coordinated schedules cost less than crews waiting on framing or delivery delays |
We'd rather walk your plans with you and give you real numbers than throw out a broad range that doesn't mean much for your specific build.
Pre-Siding Checklist Before the Wall Closes Up
Whether we're doing your install or you're evaluating another crew's work before cladding goes on, these are worth confirming at every opening:
- Sloped sill pan flashing installed at every opening, not just the ones facing prevailing weather
- Housewrap integrated in correct shingle-lap order, overlapping down and out
- Head flashing with a drip cap above every window
- Corrosion-resistant fasteners and flashing metals used throughout
- Window certified for the applicable Canadian code requirements, with documentation kept for your records
- Photos taken of flashing details at each opening before they're covered by cladding
- Interior air-sealing done separately from, not instead of, exterior water management
If you're planning a new build in Aldergrove and want a crew that treats the window install as a one-shot, get-it-right job rather than a quick trade-day, we're happy to walk your plans and put together a straightforward, no-pressure estimate — just fill out the form below.