What's the real difference between new-construction and replacement window installation?

New-construction windows go into a framed, unfinished rough opening before siding goes on, using a nailing fin fastened directly to the sheathing and integrated into the weather barrier. Replacement windows fit into an existing finished opening without disturbing the surrounding wall, which limits access to flashing details. New construction gives a contractor full access to build the flashing and drainage system correctly from the ground up.

What should I ask a contractor before hiring them for new-construction window install?

Ask them to walk you through their flashing sequence — specifically the sill pan, shingle-lap order, and fastening schedule — rather than just the window brand they use. Also confirm they're licensed and bonded in Washington and ask how they coordinate with your framer or builder on scheduling. A contractor who can explain their process step by step is a better sign than one who only talks about the window product itself.

Do you install a specific brand of window, or can you work with what our builder already spec'd?

We install to whatever window line your builder, architect, or budget calls for — our focus is on correct flashing and installation regardless of brand. If you haven't chosen a product yet, we're happy to walk through frame material and performance options suited to a coastal Whatcom County site.

What window ratings actually matter for a coastal Whatcom County build?

U-factor (how well the window resists heat loss) and condensation resistance matter most here, since Cherry Point sees a lot of temperature and humidity swings tied to the marine climate. Air infiltration ratings are also worth checking, since driving rain will find any gaps in a poorly sealed unit before it ever finds a gap in the flashing.

Does the moss and algae common around Birch Bay actually affect windows?

Indirectly, yes — moss and algae thrive on shaded, damp trim and sills, and sustained moisture in those areas is often a sign that water isn't draining away from the window the way it should. It's less about the moss itself damaging the window and more that heavy growth is a visible clue that the drainage and flashing details underneath may need a closer look.

New-Construction Windows in Cherry Point, Birch Bay

Building New in Cherry Point? The Windows Are Only Half the Job

If you're framing a new home in the Cherry Point area — whether it's a waterfront lot facing the Strait or a build set back among the trees off Birch Bay-Lynden Road — the window install is one of the few construction steps you can't easily fix later. Once siding, trim, and interior finish go on, a bad flashing detail is buried. In Whatcom County's marine climate, a buried mistake doesn't stay quiet for long.

Birch Bay Siding Company installs new-construction windows as part of full exterior builds, and we treat the window opening as a system, not a single product. The window unit matters, but the flashing, the weather-resistive barrier tie-in, and the sill detail are what decide whether that window is still performing correctly in fifteen years.

Why Cherry Point's Climate Is a Real Design Factor

Cherry Point sits right on the Strait of Georgia, and that proximity to saltwater changes what a window install needs to survive. Three things drive most of our decisions on a new build out here:

Salt Air

Airborne salt accelerates corrosion on exposed fasteners, hinges, and hardware, and it can dull or pit lower-grade finishes over time. It doesn't ruin a window overnight, but it rewards frame materials and hardware finishes that were chosen with a coastal environment in mind, not a generic inland spec.

Driving Rain

Storms coming off the water hit this stretch of coastline sideways more often than straight down. Wind-driven rain finds every gap in a rough opening that isn't properly flashed and shingled into the weather-resistive barrier. A window that's simply "caulked in" will eventually leak here — it's a matter of when, not if.

A Long Moss Season

Whatcom County's wet season runs long, and shaded exterior surfaces stay damp for extended stretches. Moss and algae growth on sills, trim, and nearby siding isn't just cosmetic — sustained moisture against wood trim or an undersized sill pan is exactly what leads to hidden rot behind an otherwise good-looking window.

What "New Construction" Windows Actually Means

New-construction windows are installed into a framed, unfinished rough opening before siding and exterior trim go on — as opposed to replacement windows, which get inserted into an existing finished opening. That difference matters because new-construction installs give us full access to the sheathing, the WRB, and the rough opening itself. Done right, this is the strongest, most weathertight way to install a window. It's also unforgiving: every layer has to go on in the correct order, because once it's covered, it's covered.

Most new-construction windows use a nailing fin (also called a nail flange) that fastens directly to the sheathing and gets integrated into the weather-resistive barrier in shingle-lap fashion — meaning each layer overlaps the one below it, so water is always directed outward and down, never trapped behind the wall assembly.

Choosing a Frame Material for a Cherry Point Build

There's no single "best" window material for every project — it depends on budget, the home's design, and how much upkeep an owner wants to take on. Here's how the common options hold up against this specific climate:

Frame Material	Salt Air / Moisture Behavior	Maintenance	Notes for This Area
Vinyl	Does not corrode; welded corners resist water intrusion when installed correctly	Low — occasional cleaning	Strong value option; verify a reinforced frame for larger openings
Fiberglass	Excellent — dimensionally stable, resists warping in wet/dry cycles	Low	Handles temperature swings and coastal moisture well; higher upfront cost
Wood-clad	Good if cladding and flashing are done right; exposed wood needs protection	Moderate to high — finish and sealant checks over time	Best suited to homes where interior wood sightlines matter most
Aluminum	Prone to corrosion near salt water unless marine-grade and properly finished	Moderate	We generally steer new builds here toward other materials unless the design calls for aluminum's narrow sightlines

We're not tied to one brand or product line — our job is to install whatever window system fits your budget and your builder's or architect's spec correctly. What we won't do is compromise on the flashing and drainage details underneath it, regardless of which window goes in.

Our New-Construction Window Installation Process

The sequence matters as much as the materials. On a Cherry Point build, this is roughly how a correct install goes:

Rough opening check. We verify the opening is square, level, and sized correctly before the window ever gets set — a slightly out-of-square opening causes operational and sealing problems that show up later.
Sill pan installation. A sloped, waterproof sill pan goes in first, so any water that ever does get past the window has a path back outside instead of soaking into the framing.
WRB and flashing tape integration. The weather-resistive barrier and flashing tape are shingle-lapped around the opening — sides first, then the top — so every layer sheds water onto the layer below it.
Setting the window. The unit is set into the sill pan, shimmed level and plumb, and fastened through the nailing fin per the manufacturer's schedule — not just tacked in a few spots.
Head flashing. A head flashing detail directs water around and away from the top of the window rather than letting it run down the face of the frame.
Sealant and backer rod. Where sealant is called for, we use the right joint width and backer rod so the bead can actually flex, instead of a thick, unsupported caulk line that cracks in a season or two.
Interior and exterior trim. Trim and finish work close everything out once the flashing sequence is verified.

Mistakes We See When We're Called in Later

We occasionally get asked to look at a window that's a few years old and already showing problems. On new construction, the recurring issues almost always trace back to one of these:

Flashing tape applied out of shingle-lap order, so water gets directed behind the WRB instead of over it
No sill pan, or a flat one that doesn't drain
Sealant used as the primary water barrier instead of a backup to proper flashing
Fasteners skipped or under-driven around the nailing fin, leaving the window loose in the opening
Trim installed tight against the siding with no room for the assembly to shed water
Hardware or fasteners not rated for a coastal environment, leading to early corrosion

Every one of these is preventable with the right sequence the first time — which is also why fixing them after the siding and trim are on is far more disruptive and costly than doing it right during the build.

A Simple Checklist for Your Build

If you're working with a builder or general contractor and want to confirm your window install is being handled correctly, ask whether these are part of the plan:

Sloped sill pan under every window, not just a flat sill
Flashing tape and WRB integrated in proper shingle-lap sequence
Full fastening schedule followed on the nailing fin, per manufacturer spec
Head flashing installed above each window
Backer rod used with sealant joints, not sealant alone
Frame material and hardware finish appropriate for a saltwater-adjacent site
Rough openings checked for square and level before the window is set

Why Local Installation Experience Matters in Cherry Point

A window flashing detail that works fine in a dry inland climate can fail here within a few wet seasons. Crews who don't regularly work the Whatcom County coastline sometimes install to a generic spec that ignores driving rain and salt exposure — and the home doesn't show the consequences until well after the crew is gone. We build and side homes in the Birch Bay and Cherry Point area regularly, so the flashing sequence, material choices, and hardware decisions on your project already account for the conditions your house will actually face, not a textbook average.

We also coordinate directly with builders and framers so the window install lines up with the rest of the exterior envelope — siding, trim, and weather barrier all working as one system instead of separate trades hoping their work matches up.

Get a Straight Answer for Your Project

Every new build is a little different — lot exposure, window count, frame material, and budget all factor into the right approach. If you're planning new construction in the Cherry Point or Birch Bay area and want a straightforward look at what your window install should involve, reach out for a free, no-pressure estimate using the form below.