What does "custom windows" actually mean, versus just buying a standard window?

It means the window unit is built or ordered to match the exact dimensions and proportions of your home's opening, rather than choosing the closest available stock size and adjusting the opening to fit. It matters most on older homes where the rough opening doesn't match today's standard manufactured sizes. On newer construction built to current standard dimensions, a well-fitted stock window is often perfectly appropriate.

How do I know if a contractor is actually qualified to handle custom window sizing, not just standard installs?

Ask how they measure and verify a rough opening before ordering, and ask them to walk through their flashing and sill-pan plan in plain terms rather than a brand pitch. Confirm current Washington contractor licensing and active liability insurance. A contractor who can explain what happens if the opening turns out to be out of square, rather than assuming it won't be, is usually the one who's done this before.

Do custom-sized windows cost significantly more than standard stock windows?

Custom sizing typically costs more than an off-the-shelf stock unit, since it's manufactured to order rather than mass-produced in common sizes, and lead times tend to run longer too. The added cost is usually worth it when the alternative is forcing a stock size into an opening it wasn't built for, which tends to create bigger problems down the line. We'll give you real numbers for your specific project rather than a broad estimate.

Can I get custom windows in double-pane or triple-pane glass, or is that only available in standard sizes?

Most manufacturers offer both double- and triple-pane glass packages in custom sizes, so glass performance isn't usually a limiting factor. Double-pane is standard and performs well for most Sehome homes; triple-pane adds insulation value and can help with condensation on especially cold surfaces, but the extra cost doesn't always pay off unless the home has high heating demands already.

Does Sehome's mix of older and newer homes mean every house here needs custom windows?

No. Newer infill construction built to current manufactured dimensions often takes a properly fitted stock window without any issue. It's older and mid-century homes, along with houses that have a history of ill-fitting prior replacements, where custom sizing tends to be the honest answer. We check each home's actual opening rather than assuming one approach fits the whole neighborhood.

Custom Windows in Sehome, Bellingham

Custom Windows in Sehome: Fitting Older Openings the Right Way

Sehome is one of Bellingham's established central neighborhoods, and its housing stock reflects that: a mix of older homes, mid-century construction, and newer infill sitting close to Sehome Hill. That mix is exactly why "custom windows" comes up so often on projects here. A lot of older and mid-century houses in this part of Bellingham were framed with window openings that don't match today's standard manufactured sizes, and some have already had one round of ill-fitting replacement windows installed that never quite sealed the gap correctly. Custom windows, meaning units built or ordered to fit the actual opening rather than forcing the opening to fit a stock size, are often the honest answer on these homes.

Bellingham Window Co installs, repairs, and replaces windows across Whatcom County, including Sehome, and we also handle siding, roofing, and decks, because a window is never an isolated product. It has to work with the framing, flashing, and siding around it. In a climate that delivers salt air, driving rain, and a moss season that can run most of the year on shaded slopes, a poorly fitted window is one of the fastest ways water finds its way into a wall.

Why Custom Sizing Matters More in Sehome Than in Newer Developments

Non-Standard Openings in Older Framing

Homes built before modern manufactured window sizing became standard often have openings that are slightly taller, narrower, or otherwise out of spec compared to what a big-box or standard catalog window is built to fill. Forcing a stock-size window into one of these openings usually means extra shimming, filler material, or a wider reveal than the window was designed for, and every one of those workarounds is a place water can find its way in. Custom-sized units are built to the actual rough opening, which keeps the installation clean and the flashing detail straightforward instead of improvised.

Mixed Architectural Eras on the Same Block

Because Sehome's housing spans older construction, mid-century homes, and newer infill often standing near each other, window proportions and styles vary block to block and sometimes house to house. A custom window order lets a homeowner match the visual proportions of an older home, keep divided-lite patterns or trim details consistent with the house's original character, or simply get the sightlines right on a mid-century design where standard modern frame widths would look out of place. This isn't about aesthetics for their own sake; a window that fits the wall's proportions also tends to fit the opening's actual dimensions more precisely.

Prior Replacement Windows That Were Never a Good Fit

We regularly find homes in this neighborhood where a previous window replacement used the closest available stock size rather than a true custom fit, with gaps packed with foam or trim built up to hide the mismatch. Those shortcuts tend to surface as drafts, fogging, or water staining years later. When we replace a window like that, we treat it as a chance to correct the opening and install a properly sized unit, not just swap in another close-enough size.

What This Climate Does to Windows in Sehome

Sehome sits inland of the immediate waterfront but still well within reach of the salt-laden air that moves through Bellingham off the Salish Sea, and its terrain toward Sehome Hill means some homes sit on sloped lots where drainage plays a real role in how water moves against the lower courses of a wall.

Climate Factor	Effect on Windows	What a Correct Install Does About It
Salt-carrying marine air	Accelerates corrosion on hardware, screen frames, and lower-grade fasteners	Corrosion-resistant hardware and fasteners specified for the exposure, not just the cheapest catalog option
Wind-driven, sideways rain	Pushes water into flashing, head trim, and the sill pan rather than just running off	A properly pitched sill pan and flashing sequence that sheds water outward, not a bead of caulk standing in for flashing
Long moss and mildew season	Holds moisture against shaded sills and frames, especially under mature tree cover	Materials and finishes chosen for moisture exposure, plus sills designed to drain rather than pond
Sloped lots and drainage	Can direct more water toward lower-level windows on some Sehome properties	Grading and drainage checked as part of the window assessment, not assumed to be someone else's problem

None of this means every window in Sehome needs custom sizing. Newer infill homes built to current manufactured dimensions often take a properly fitted stock window without issue. The point is that we check the actual opening on every project rather than assuming a standard size will work just because it's the default option.

What a Correct Custom Window Job Involves

A custom window project has more steps than ordering a stock size off a shelf, and skipping any of them is how a good-looking window ends up leaking within a couple of winters.

Precise measurement of the existing rough opening, including checking for square, level, and any settling that's shifted the frame over time
An honest assessment of the opening's condition: sound framing versus hidden rot, moisture damage, or prior repair shortcuts
Correct sizing and, where relevant, matching sightlines, trim profile, or divided-lite pattern to the home's existing character
A flashing plan built around the specific wall assembly, not a generic detail applied regardless of siding type or orientation
A sill pan that's actually pitched to drain outward rather than sitting flat and holding water against the frame
Frame material and hardware finish selected with this region's salt exposure and moisture load in mind
Proper integration with the surrounding siding and trim so the finished job looks intentional, not patched

Full-Frame Replacement vs. Insert Replacement in Sehome

One of the first decisions on any window project is whether to do a full-frame replacement, removing the old window down to the rough opening and rebuilding flashing from scratch, or an insert replacement, fitting a new window into the existing frame. Insert replacement is faster and less disruptive to surrounding siding and trim, and it can work well when the existing frame is sound, properly flashed, and close enough to standard dimensions. Full-frame replacement takes longer and costs more, but it's the honest answer when an opening needs true custom sizing, when there's already moisture damage at the sill or jambs, or when a prior installation's flashing was never done correctly. Given how often we find non-standard openings or old shortcuts in this neighborhood, more Sehome projects lean toward full-frame than a newer subdivision would.

Signs a Sehome Home Needs a Custom Window Assessment

Visible gaps, uneven reveals, or trim built up to hide a mismatch between the window and the opening
Fogging or condensation between panes, often a sign of a failed seal on an aging unit
Drafts near a closed window, especially on an older or previously replaced unit
Soft, discolored, or spongy sill and trim material, particularly on shaded or downhill-facing walls
Difficulty opening, closing, or latching a window that used to operate smoothly
Water staining on interior walls or ceilings near a window, which can point to a flashing or sizing problem rather than just an aging seal

Any one of these is worth a professional look, and on an older Sehome home it's worth asking specifically whether the opening itself, not just the window unit, is part of the problem.

Repair, Reseal, or Replace?

Not every issue calls for full replacement, and we don't default to recommending one. We look at the age and condition of the existing window, whether the problem is isolated or shows up across several openings, and whether the opening itself is a standard size or something that will need a custom order. A single window with a failed seal on an otherwise well-fitted unit is often a straightforward repair. A house with multiple ill-fitting replacements from a previous project, or visible sill rot behind the trim, is usually more honestly addressed with a custom replacement plan, done in phases if budget requires it.

Frame Materials That Hold Up in This Climate

Custom sizing is only half the equation. The frame material also has to handle sustained moisture, salt-influenced air, and a long shaded season without becoming a maintenance burden.

Frame Material	Moisture & Corrosion Behavior	Custom-Order Availability	Typical Maintenance
Vinyl	Won't rot; seams and welds can be a weak point if fabrication or installation quality is poor	Widely available in custom sizes from most manufacturers	Low; occasional track and weep-hole cleaning
Fiberglass	Dimensionally stable, resists moisture and corrosion well	Available custom, though lead times can run longer than vinyl	Low
Wood, painted or clad	Attractive and often the closest match for older architectural styles, but vulnerable at joints and sills without upkeep	Well suited to custom orders matching original proportions	Higher; regular paint or finish maintenance
Aluminum	Conducts cold and can corrode over time in salt-influenced air unless well-finished	Available custom, less common choice in this climate	Moderate

For a lot of Sehome's older housing stock, wood-clad or fiberglass custom units end up striking the right balance between matching the home's original look and holding up to the climate, but the right call depends on the specific house, its exposure, and the homeowner's maintenance appetite. We'll walk through the honest trade-offs rather than defaulting to whatever's easiest to order.

Why a Local Crew That Already Works in Sehome Matters

A crew that measures and installs windows across this neighborhood through every season learns the specific quirks of Sehome's housing stock: which blocks tend to have non-standard openings, how prior rounds of window replacement were typically handled, and how much attention a given wall's orientation or slope needs because of shade or drainage. That local pattern recognition matters when a stock-size assumption would be wrong, or when a "quick" insert replacement would actually be covering up a sizing problem that needs a real fix. It also means working with someone who treats the custom window process as routine rather than an unfamiliar special order.

Beyond Windows: Siding, Roofing, and Decks

Custom windows are our focus for this page, but the same climate that wears on a window wears on the rest of a Sehome home's exterior too. We also handle siding, roofing, and deck construction, and on siding specifically we install James Hardie fiber cement as our standard, chosen for how it holds up against sustained moisture and moss compared to lower-cost alternatives. If a window project turns up moisture damage in the surrounding siding or trim, we can address it as part of the same conversation rather than sending you to find a second contractor.

Get a Free, No-Pressure Estimate

If your Sehome home has windows that don't quite fit their openings, are drafty, fogging, or original to a house that's due for an update, we're glad to take a look and give you a straightforward, honest read on what it actually needs. Reach out using the form below to schedule a free estimate, no pressure, no upsell script.