What's the actual difference between new-construction and replacement windows?

New-construction windows have a nailing flange and are installed into open framing before siding goes on, with flashing built in from scratch. Replacement windows fit into an existing finished opening without disturbing the surrounding siding or trim. The two require different techniques, and a contractor experienced in one isn't automatically set up to do the other well.

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

Ask how they handle sill pan flashing and whether they follow the specific window manufacturer's installation instructions, since deviating from those can void the warranty. Ask who coordinates the handoff between window installation and siding, since that seam is where most moisture problems start. It's also fair to ask how they sequence work around a general contractor's schedule if you're working with a builder.

Does it matter which window brand I choose, or is installation the bigger factor?

Installation quality matters more than brand for long-term performance — a well-installed mid-range window will outlast a premium window installed with a skipped flashing step. That said, sticking with an established manufacturer matters for parts availability and warranty support down the road. We work with several major manufacturers and can talk through what fits your budget and the opening sizes on your plans.

What's condensation resistance and why does it matter for a window I'm installing new?

Condensation resistance is a rating that measures how well a window resists moisture forming on the interior glass and frame in cold, humid conditions. In a climate with cool, damp winters like ours, a window with poor condensation resistance can fog up regularly and eventually stress the sill and interior trim. It's worth checking this rating alongside U-factor when comparing window options, not just the price.

Does Kendall's setting near the water and tree cover change how new-construction windows should be installed?

Salt-laden coastal air can accelerate corrosion on lower-grade fasteners and hardware over time, so we pay attention to what's specified for exposed components. Wooded, shaded lots common around Kendall also mean walls stay damp longer after a storm, which makes a correct flashing sequence even more important than on a fully exposed, sun-drying site. Neither factor changes the fundamentals of a good install, but they raise the cost of getting it wrong.

Kendall New-Construction Windows, Built for Whatcom Weather

New-Construction Windows in Kendall: What the Term Actually Means

"New construction" windows are a different job from window replacement, even though both end with a window in a wall. On a new build, an addition, or a shop/ADU going up in the Kendall area, we're working with a rough opening that has never had a window in it. There's no old frame to remove, no existing flashing to patch around, and no compromises made for whatever was installed decades ago. That's an advantage — but it also means every layer of the opening has to be built correctly the first time, because there's nothing hiding a mistake later. Get the flashing sequence wrong on a new-construction opening and you won't see the consequence for a year or two, until moisture finds its way behind the siding.

We treat new-construction window work as part of the building envelope, not as a standalone task. The window, the weather-resistive barrier, the flashing, and the siding all have to work as one system. That's the same approach we bring to siding jobs throughout Ferndale and the surrounding Whatcom County communities, and it's why we don't hand off window installation to a separate crew that doesn't know how the rest of the wall assembly is being built.

Why Whatcom County's Climate Demands a Careful Install

Kendall sits inland from the coast, but it still gets the same weather systems that move through the rest of Whatcom County — long stretches of driving rain, wind-driven moisture that pushes water sideways into wall assemblies, and a damp season that stretches from fall through spring. Add in the tree cover common around Kendall properties, and you get more shade, slower drying, and a longer moss season on roofs and north-facing walls than homes see in drier parts of the state.

None of that is a problem for a window opening that's built correctly. It becomes a problem when a nailing flange is caulked instead of properly flashed, when a sill pan is skipped, or when house wrap laps the wrong direction at the top of the window. In a dry climate those shortcuts might never surface. Here, with rain loading the wall for months at a stretch, they show up as stained sheathing, soft trim, or interior sill rot within a few winters. Building for this climate means assuming water will reach the opening and giving it a way out — not assuming caulk will keep it out forever.

Salt Air and Coastal Influence

Whatcom County's proximity to salt water also plays a role, even for properties set back from the shoreline. Salt-laden air accelerates corrosion on fasteners, hinges, and lower-grade hardware over time. It's one more reason we pay attention to the fastener and flashing materials specified for a job, not just the window unit itself.

What a Correct New-Construction Window Install Involves

A new-construction window installation isn't just setting a unit into a hole and screwing it to the studs. Done right, it follows a specific sequence, and skipping steps out of order is one of the most common ways new builds end up with hidden moisture damage.

The Flashing Sequence

Sill pan flashing installed first, sloped slightly to the exterior so any water that gets past the window has somewhere to go
Weather-resistive barrier (house wrap) cut and folded into the opening before the window goes in, not caulked over it afterward
Window set plumb, level, and square in the opening, with shims at the correct load points — not just at the corners
Side flashing tape applied over the nailing flange, followed by head flashing with a drip cap so water sheds away from the top of the unit
House wrap integrated over the head flashing in proper shingle-lap order, so every layer drains onto the one below it

Air Sealing and Insulation

Once the window is flashed and weathered in, the gap between the frame and the rough opening gets sealed from the inside — typically with a low-expansion foam or backer rod and sealant rated for window applications. Overfilling this gap with high-expansion foam can bow the frame and cause the sash to bind, so this step takes a lighter touch than most people expect. Proper air sealing here also matters for energy performance and for keeping condensation from forming on interior trim during cold snaps.

Choosing the Right Window for a Kendall Build

Frame material and glass package both affect how a window performs in a wet, moderate-temperature climate like ours. There's no single "best" answer for every project — it depends on budget, the style of the home, and how much upkeep the owner wants to take on.

Frame Material	Moisture Behavior	Upkeep	Typical Fit
Vinyl	Won't rot; seams and welds matter for long-term weather tightness	Low — no painting or sealing needed	Most new builds; strong value for the performance
Fiberglass	Very stable in wet/dry cycling, resists warping	Low, factory-finished	Larger openings, higher-end new construction
Wood or wood-clad	Needs a sound exterior cladding and consistent finish maintenance to keep moisture out	Higher — finish maintenance is part of ownership	Homes where the interior wood look is a priority
Aluminum	Conducts cold and can condense in our damp winters unless thermally broken	Low	Limited use; mostly commercial or specific architectural needs

For glass, we look at the U-factor (how much heat the window loses) and the condensation resistance rating, not just the price tag. Whatcom County's combination of cool, humid winters and mild summers means a window with decent condensation resistance pays off in fewer fogged-up mornings and less moisture stress on interior sills and trim.

Our Process: Rough Opening to Trim-Out

Review the rough openings against the window schedule and manufacturer specs before any unit arrives on site
Confirm WRB and flashing materials are compatible with the window manufacturer's installation instructions — this affects warranty coverage
Install sill pan flashing and dry-fit the window before final setting
Set the window plumb, level, and square; fasten through the nailing flange per manufacturer spacing
Complete the flashing sequence — jambs, then head, integrated with the house wrap
Air-seal the interior gap and confirm smooth sash operation before moving on
Coordinate with siding and trim installation so the exterior finish laps correctly over the flashing, never under it

That last step is where a lot of new-construction window problems actually originate — not in the window install itself, but in how the siding crew treats the flashing afterward. Because we do both the window install and the siding on many of our projects, that handoff doesn't rely on two separate contractors guessing at each other's work.

Common Mistakes We Watch For

Whether we're installing new or correcting a builder-grade job before siding goes on, these are the issues that show up most often in wet-climate new construction:

Sill pan flashing skipped or improvised with caulk alone
House wrap taped in the wrong lap order, directing water behind the window instead of away from it
No drip cap or head flashing above the unit
Windows shimmed only at the corners, leading to a bowed frame and a sash that won't seal
High-expansion foam used for the interior air seal, distorting the frame
Siding installed tight against the window trim with no gap for a proper sealant joint

Why a Local Crew Matters for Kendall Projects

Kendall's setting — more rural and wooded than the center of Ferndale — often means longer driveways, well and septic considerations, and scheduling around a general contractor's own timeline on a new build. A crew that regularly works this part of Whatcom County already understands how to plan a window and siding install around those realities, rather than treating every property as a standard in-town lot. It also means we're not learning the region's weather patterns on your project — we've already seen how driving rain and shaded, damp sites affect drying time and installation sequencing here.

Being local also matters after the job is done. If a question comes up during the first wet season — a drafty spot, a question about a warranty claim — we're not a call center away, we're down the road.

What to Expect the First Year

A correctly installed new-construction window shouldn't need attention for years. That said, it's worth doing a simple check each fall before the rainy season sets in: confirm the exterior caulk joint between the trim and siding is intact, look for any staining at the sill or below the window on the interior, and make sure the sash still operates smoothly. Wood framing settles slightly in the first year or two after construction, and a quick check catches anything worth adjusting before it becomes a bigger issue.

If you're planning new construction, an addition, or an ADU in the Kendall area and want windows installed by a crew that treats the flashing and siding as one system, we're happy to take a look at your plans and provide a free, no-pressure estimate — no obligation, just a straight answer on what your project needs.