by jef safi

Regular style is the angled bay window, and it is protrudes from the house and slants back to the wall at a  45 degrees. A box bay is square-the side sash come straight off the house at 90 degrees. A box bay with a glass roof called a garden bay or greenhouse window. All major window factories usually offer angled bay windows in  30 or/and 45 degree install; fewer manufacturers produce 60 degree bay windows.

Sizes: Every bay window comes in hundreds of standards or custom sizes to fit any opening in any house. Standard window size ranges in width from three feet six inches to ten feet six inches, and in height from three feet to six feet six in.

Wood, Vinyl or Aluminium? Most bay windows are made of wood – it is less expensive. Exterior bay window finish options are primed wood, extruded vinyl & wood clad in low maintenance aluminum or vinyl. Primed wood bay windows are cheap, but they need special bay window treatment. Prined wood bay windows must be painted and periodically scraped & repainted to prevent rot. Vinyl windows are also affordable and maintenance free, but their frames include vinyl on interior surfaces. Clad windows usually more expensive, but they offer a low maintenance vinyl or aluminum exterior & a handsome all wood interior.

Most bays come with insulated glazing 2 panes separated by an air space. If you want higher energy efficiency, order the window with argon gas between the panes, or opt for low  glazing that admits solar heat in winter and reflects it in summer. Homes in cold-weather climates might benefit from triple glazing (three panes, two air spaces), which provides fifteen to twenty-five % higher energy efficiency than standard insulated glazing.

Pricing: Although prices vary widely depending on size and window construction, expect to pay between 0 and ,100 for a three feet hight by six feet wide vinyl clad 30 degree casement bay window. A custom made unit will cost at least twenty % more and take 4-6 weeks for delivery, compared with less than a week for most standard-size bays. That’s why it’s important to shop around for the window that best suits your home, budget, and time schedule.

Whichever bay window you’re considering, review the following five questions before you buy.

Size:  It’s easier and cheaper to put in a bay the same size or smaller than the old window. A wider bay requires a larger opening and a new header — and typically adds 0 to 0 to the job. However, a larger window will bring more light into the room and create a greater visual impact inside and out.

Sash:  There’s no set rule regarding which style sash — either casement or double-hung — a bay should have. Often, the bay sash match those on the other windows on the home, but they don’t have to. Pick the style you like best. Taller, narrower bays usually look better with casement sash. Shorter units are most attractive with double-hung sash. You’ll also find that the center window of a bay usually is fixed. But it, too, can be ordered with operable casement or double-hung sash in smaller sizes.

Bay Window Support: Bay windows must be supported from above with steel cables bolted to the overhead framing or from below with braces. Both systems work great, but support cables are much less obtrusive because they’re hidden inside the bay window frame. Not every manufacturer offer support cables (because of their price), but those cables can be bought separately and adapted for use on virtually any bay window.

Is there an eave above the window? Bay windows often are tucked beneath an eave, with the space between the window top and underside of the soffit filled with insulation & hidden by trim boards. Before choosing a bay window, measure the depth of the eave horizontally. Then order a unit that’s shallow enough to fit beneath it if you can. Most 30 degree bay windows are twelve-fourteen inches deep, and 45 degree units range from about sixteen-twenty two inches deep. Box bays and 60 degree bays usually are about 18 to 24 inches deep.

What if there’s no eave above it? When a bay window is installed on a gabled end or in the middle of a wall — and there’s no roof overhang right above it — a small roof, or skirt, must be built over it. Roof skirts must be built above any window that sticks out beyond an overhanging eave.

Finally, be sure your contractor has wide experience in installing bay windows - especially if the old opening needs work (has to  be enlarged). Even some window replacement specialists aren’t familiar with the idiosyncrasies of putting in bays.