Loose or incorrectly installed hardware may prevent a bay window from closing. Follow the hardware installation instructions as explained in the manufacturer's directions. Tighten the screws on loose handles and locks when necessary. Some window models come with hinge adjustment inserts. The inserts adjust the sash if the window does not properly close. These adjustments usually become necessary when a house settles.
Dirt particles and residue accumulating around a bay window and its frame prevent it from completely closing. Clean the windows with a gentle solution of water and a mild liquid detergent. Clean along all sides of the window and inside the frame. Drying the window and frame thoroughly prevents wood warping from moisture exposure. Wait until the windows and frames are completely dry before closing the windows.
On casement-type windows, bring the windows in by moving the cranks. On double-hung models, push the windows down until they are tight against the inside of the sill. The window locks won't close until the window is closed tightly. If the casement window has two locks, close the lower lock first.
Cleaning the windows every three months keeps dirt buildup to a minimum. In coastal areas, cleaning the windows at least once a month prevents salt buildup. Salt may buildup on hardware and joints, causing corrosion that affects the window's operation. After cleaning, lubricating all moving parts, including hinges and locks, ensures the windows operate smoothly.