Cost guide
Bow and bay window cost: what you are actually paying for
Short answer
Our bay and bow windows start from £1,850 fully fitted, based on a standard three facet bay in a semi. The number of facets, whether the bay supports the wall above, the roof and sill work, and your glass and colour choices are what move a quote up from there. A bay is one structural job, so it should be priced as one.
Why a bay is not four windows
It is tempting to count the panes and multiply by a window price. The trouble is that the frame of a bay is often helping to hold up the brickwork or small roof above it. When the old frame comes out, that load has to go somewhere. A proper quote allows for propping on the day and, where the bay is load bearing, reinforced jack posts in the corners so the new frame carries the weight permanently.
Quotes that price a bay as separate windows tend to leave the support, the sill and the roof junction out, and those reappear as extras once the old frame is out.
What pushes the price up or down
- Facets: three, four or five sections, and square, splayed or curved bow layouts.
- Structure: whether corner posts carry load and need jack posts.
- Head and roof: a small lead or tiled roof above the bay may need making good where it meets the new frame.
- Sill: replacing or capping a rotten sill adds material and time.
- Opener layout: more opening sashes mean more hardware.
- Glass: laminated glass on accessible panes, acoustic or triple glazing, and recreated leaded or stained top lights.
- Colour: white, foils, woodgrain and dual colour finishes across the whole front.
Bay or bow: the difference in cost terms
A bay usually has straight angled sides and a flat front. A bow curves gently outward using more, narrower facets. More facets means more corner joints, more sealing line and more frame per metre of glass, so a bow of the same width generally costs more than a three facet bay. Either can be finished as sash, casement or flush casement units to match the rest of the house.
What a fair bay quote should include
Before comparing numbers, check each quote lists the same things. Ours includes all of these in the fixed price.
- Structural check of the bay head at survey
- Propping and jack posts where the bay carries load
- Removal and disposal of the old frame
- Sill and roof junction detailing and making good
- The house left secure and weathertight the same day
- Building Regulations self certification and our 10 year insurance backed guarantee
Timing
A standard three facet bay normally takes one full day. We never leave an open bay overnight. Bigger bows, or bays where the roof above needs work, can take longer, and we tell you at survey if that applies.
Common questions
Get a free fixed quote
Call 07925 319937, open Monday to Sunday 9am to 6pm, or send the form.