The window seat is cold, the corner trim is pulling away, and the whole thing sags a little.
Half the triple-deckers in this city were built with bay windows out front, and a good number of those are now held together by paint and optimism. We replace them. A bay hangs off the wall instead of sitting in it, so the header, the braces above and the seat framing below all have to carry the weight before any glass goes in.
What I will not do is set a new unit on a seat board with rot under it and run trim over the top, because that is the sag that turns a bay window seater into a diving board. Span, access and whatever the framing looks like once the old unit is out all move the price.
Below: how the work goes, the canted and casement shapes, where we work, and the questions people ask first. Call (508) 406-9528 and I will come look.
Adding A Bay Window
Adding a bay window where a flat opening used to be is framing work first and glass second. We cut the wall back, set a header sized for the new span, and carry the weight on knee braces underneath or cables anchored into the framing above the unit. Then comes the roof cap, flashed into the siding, and insulation at the head and under the seat.
Skip the support and the seat board dips, the sashes start to bind, and the caulk lines open up. Skip the cap flashing and water goes straight for the header.
Most of the new openings we cut at Worcester Window Replacement are in three-decker front parlors, where that wall is holding something up. Opening width, whether it's load-bearing, and how much siding and interior trim gets rebuilt are what set the bay window installation cost. Want a bay window seater deep enough to actually sit on? Tell us before we order, because that changes the projection.
Kitchen Bay Window
A kitchen bay window almost always sits over the sink, which makes it the steamiest opening in the house and the least forgiving one. We size the header first, hang the unit on cable supports tied back into solid framing, then build and flash the roof cap so meltwater runs off instead of pooling where the seat board meets the wall. Under that board goes rigid foam and a sealed knee wall.
Skip that step and you have a cold shelf that sweats onto your countertop every time a pot of pasta comes to a boil, and once the unit settles even a little, the sash under the faucet stops latching.
Projection depth, whether the counter and backsplash have to be cut back, and how much bay window seater you want built out drive the bay window installation cost more than the glass does.
Bay Window Vinyl
Bay window vinyl is what most of the openings I quote here end up being, and for good reason: welded corners, multi-chamber frames, and no scraping and repainting the exterior every few summers. What vinyl won't do is carry weight on its own. A vinyl bay needs reinforcement, either steel or aluminum through the head and the mull posts, or cable and knee braces tied back into solid framing above the opening.
Skip that step and the head sags, the sashes start binding, and by the second year the top rail is rubbing every time you crank one open. Dark exterior colors run hot on the south face too, so I'd rather spec a laminate skin made for heat than a painted frame. Frame size, the glass package, and whether the seat and roof get rebuilt all change what bay windows cost.
Bay Window Replacement
Replacing bay windows is really three jobs stacked into one: pull the old unit, deal with whatever the water did to the seat board and the framing under it, then set the new one dead level and hang it off the header the way it's meant to hang. That last part is where I see things go wrong.
A bay carries its own weight out over thin air, so when the support cables or knee braces get skipped, it droops inside a year or two and the flanker sashes quit latching. Width, whether you want fixed glass in the center or operating sash all the way across, and how far the rot has got into the framing are what drive what bay windows cost.
If the little roof over the unit is shot, that comes into it as well.
Box Bay Window
A box bay window pushes straight out at right angles, flat across the front with two square returns, so it reads as a shallow bump-out rather than one of the angled bays. The part nobody thinks about is the little roof on top. It gets framed, sheathed, insulated, flashed into the wall above and then shingled or wrapped in metal.
Skip that flashing detail or leave the cavity empty and you get a cold ceiling inside the box and a stain on the head trim by the second winter, when snow sits up there for a week at a stretch. We insulate the roof and the seat board and tie the load back into framing that can actually carry it. What box bays cost moves with projection depth, roof finish, and whether the header has to be rebuilt.
Large Bay Window
A large bay window carries real weight, and that's the whole job right there. Eight feet of glass, a seat board and a roof cap over the top can hang a few hundred pounds off your wall, so it has to be held two ways: cables anchored up into the header, and knee braces underneath.
Skip either one and the nose of the unit drops a quarter inch, the miters open at the corners, and the sashes quit latching by year two.
On big bay windows we rebuild the header if the opening is growing, insulate the seat cavity and the roof void instead of leaving them hollow, and flash the cap so water goes out over the siding, not behind it. Width, glass size, framing work and second-floor access on a triple-decker are what move the number.
Canted Bay Window
A canted bay window is the classic one: flat across the front with two side sashes angled back, usually at thirty or forty five degrees, and it's what sits on the front of half the triple deckers in this city. The angle is the whole job. Cut the seat and head boards a degree off and the front unit racks, the miters open, and you'll feel air on your ankles by fall.
So we template the angle off the existing opening, build the seat over rigid insulation, and carry the weight on knee braces into the framing below or cable support into the header above. A canted bay hung off sheathing alone will sag, and once it sags the sashes stop closing. Figure most of a day per opening. A deeper projection, a rotted head board, or working above a porch roof all push that.
Casement Bay Window
A casement bay window is the one where the angled flankers crank open instead of sliding up, and it's what I push hardest when the opening sits over a kitchen sink or a radiator you can't lean across. Cranks give you the whole opening for air instead of half of it, and the screen sits on the inside where it doesn't get shredded.
What ruins these is a head that isn't shimmed dead level. Hang a heavy operating sash on a frame with any sag in it and the latch quits catching by October, and no amount of fiddling with the hinge track fixes a bowed header. We set the fixed center unit, pull a string line across it, then hang the flankers off that.
Operating units, glass package and the state of the header above are what move the price.
What the job involves
The job involves a lot more than pulling the old unit and sliding a new one in. Bay windows hang out past the wall, so the first thing I look at is how the weight gets carried: cable support anchored up into the header, knee brackets underneath, usually both. Then the roof over the top, framed, sheathed and flashed into the siding so rain runs out and not down behind your wall.
Inside, the cavity under the seat gets rigid board and sealed edges, or you'll feel it through your socks the first cold snap.
Setting one on the existing header without opening the wall to see what's above it is how you get a droop and a sash that stops latching.
Size, whether we're widening the opening, a canted bay window versus a squared box bay window, crank-out casement flankers, and second-floor staging on a triple-decker all move the number.
What it costs
What it costs depends less on the glass than on what's holding the thing up. A three-lite canted bay window in vinyl with two operable casements flanking a fixed center is one number; the same opening with a shingled hip roof over it, new knee braces and a rebuilt seat board underneath is another entirely.
Rot in the framing under the old bay moves the price more than anything on the order sheet, and nobody knows how far it went until the unit is out.
Interior trim, exterior wrap, cable support off the header, and second-floor work that needs staging all pull on the bay window installation cost. Give me a call at (508) 406-9528 with a rough width and which way the bay faces, and the figure comes off your actual framing instead of a catalog page. A casement bay window over a kitchen sink tends to sit at the friendlier end of what bay windows cost, since there's no seat to build.
When bay windows are the wrong fix
Sometimes bay windows are the wrong fix, and I'd sooner tell you that with the tape still in my hand than frame a projection into a wall that can't carry one. A second floor opening over an unsupported corner, a bedroom that needs proper egress windows, three feet of clearance between the wall and the driveway: in spots like those, a pair of double hung windows does more for the room and costs a fraction of the framing.
And if the cold you're feeling is really coming off your exterior doors or the patio doors out back, no large bay window will cure it. Neither will a canted bay window, however good it looks from the street.
On window replacement in an old triple decker, we'll often set flat units and save the kitchen bay window for the wall that can hold it.
Why choose us for this
You've had a couple of people out to look at bay windows and both of them talked mostly about glass. A bay isn't glass. It's a box hanging off the side of your house, and it lives or dies on what's carrying the weight.
What I won't do is set the unit on the old sill and treat the support cables and knee braces as a formality. That's how the nose drops by the second summer and the corner trim opens up.
Whether it's a canted bay over a kitchen sink or a box bay window in a triple-decker front room, what moves the price is the width, the header above it, the little roof and flashing on top, and what the framing under the seat has been doing in the dark. My number is rarely the low one on the pile.
The measure visit is free and obligates you to nothing.
Frequently asked questions
Do bay windows need extra support underneath?
Most bay windows hang from a cable or rod system tied back into the header above, with knee braces under the seat. When the front corners of a seat board start to dip, that support was hung wrong or skipped. We open up and check the header and sill framing before the new unit goes in, and we insulate the seat cavity and the little roof over it, because an uninsulated box is a cold spot in every cold snap.
Can you repair a bay instead of replacing the whole thing?
Sometimes. If the glass has fogged but the frame and seat are sound, we swap sashes or the insulated glass units and leave the box where it is. Soft head trim or a rotted seat board is a different story, and at that point a bay window replacement costs you less than chasing the rot twice.
What changes the bay window replacement cost from house to house?
Size, sash count, and what's behind the trim. A three-panel with casement bay window flankers runs more than a box bay window of the same width, second-floor work needs staging, and rebuilt framing or a new roof over the box adds time.
Contact Worcester Window Replacement now
Contact us about Worcester window replacement now and the first visit is mostly measuring and looking upward: the opening in three places, the header carrying the load above it, and whether the framing under the seat is still sound or has been drinking water since the flashing gave up.
Bay windows get built for your opening, not pulled off a rack. A large bay window, or a casement bay window with cranks and screens, has a lead time between the day you call and the day we install, so booking early is the whole trick to landing it before the cold sets in.
Plaster edges and interior trim come out with the old unit, and the floor and the seat below it get covered first.
Nine to five, Monday through Friday, at (508) 406-9528, and Saturdays when a job genuinely cannot sit.