A bay window is a combination of window frames built out from the face of the building. The side frames may be set at 90- or 45-degree angles to the front of the house. Curved bays are also made with equal-sized frames set at a very slight angle to each other to form a faceted curve.

The brick structure that supports the window frames may continue up through all storeys, finishing with a gable roof. Alternatively, the bay might have a brick base only, or be supported on brackets, with a flat or pitched roof.

Bay windows can break away from the main wall as a result of subsidence caused by poor foundations or differential ground movements. Damage from slight movement can be repaired once it has stabilized by repointing the brickwork and applying mastic sealant to gaps round the woodwork. However, any damage from extensive or persistent movement should be dealt with by a builder. Consult your local Building Control Officer and inform your insurance company.

Where the height of the original window permits, fit standard window frames to make up a replacement window. Various combinations of frames can be joined with shaped hardwood corner posts to set the side frames at an angle of 90 or 45 degrees. A sealant is used to weatherproof the joints between the posts and frames.

These windows are constructed on a shallow curve and normally project from a flat wall. Complete hardwood bow-window frames are available from joinery suppliers, ready for installation in a brickwork opening. A flat-topped canopy of moulded plastic is made for finishing the top of the window in place of a traditional lead-sheet covering.

Tack damp-proof-course material to the sides of the frame and the underside of the sill, then fit both the frame and the canopy into the wall opening, the outer edges of the frame set flush with the wall. Screw the frame to the brickwork. The vertical damp proofing should overlap any damp-proof course built into the wall.

Weatherproof the canopy with a lead flashing cut into the wall and dressed over the upturned rear edge of the canopy. Use mastic to seal the joints between the frame and the brickwork.

Traditional boxed-sash windows fitted with cords and counterweights can be home-made or supplied by specialists who can also fit them for you.

Alternatively, an old vertically sliding sash window can be replaced with a new frame with spiral-balance sashes.

Remove the sashes, then take out- the old frame from inside the room. Prise off the architrave, then the window boards, and chop away the plaster as necessary. Most frames are wedged in their openings, and you can loosen one by simply hitting the sill on the outside with a heavy hammer and a wood block. Lift out the frame (1) and remove any debris from the opening.

Fit a traditional sash-window frame

Standard frames joined with posts exactly like the original, making sure the wood is treated with preserver.

Set a new spring-balance type (which has a thinner frame) centrally in the window opening. Check the frame for plumb and wedge the corners at the head and sill. Make up the space left by the old box stiles with mortared brickwork (2).

Metal brackets screwed to the new frame’s jambs can also be set in the mortar joints to secure the frame.

When the mortar has set, replaster the interior wall and replace the architrave. Glaze the sashes and apply a mastic sealant to the joints between the exterior brickwork and the frame to keep rainwater out.

Decorative but functional blinds are essential window treatments for setting the color scheme and décor of a room.

A bay window is a combination of window frames built out from the face of the building. The side frames may be set at 90- or 45-degree angles to the front of the house. Curved bays are also made with equal-sized frames set at a very slight angle to each other to form a faceted curve.

The brick structure that supports the window frames may continue up through all storeys, finishing with a gable roof. Alternatively, the bay might have a brick base only, or be supported on brackets, with a flat or pitched roof.

Bay windows can break away from the main wall as a result of subsidence caused by poor foundations or differential ground movements. Damage from slight movement can be repaired once it has stabilized by repointing the brickwork and applying mastic sealant to gaps round the woodwork. However, any damage from extensive or persistent movement should be dealt with by a builder. Consult your local Building Control Officer and inform your insurance company.

Where the height of the original window permits, fit standard window frames to make up a replacement window. Various combinations of frames can be joined with shaped hardwood corner posts to set the side frames at an angle of 90 or 45 degrees. A sealant is used to weatherproof the joints between the posts and frames.

These windows are constructed on a shallow curve and normally project from a flat wall. Complete hardwood bow-window frames are available from joinery suppliers, ready for installation in a brickwork opening. A flat-topped canopy of moulded plastic is made for finishing the top of the window in place of a traditional lead-sheet covering.

Tack damp-proof-course material to the sides of the frame and the underside of the sill, then fit both the frame and the canopy into the wall opening, the outer edges of the frame set flush with the wall. Screw the frame to the brickwork. The vertical damp proofing should overlap any damp-proof course built into the wall.

Weatherproof the canopy with a lead flashing cut into the wall and dressed over the upturned rear edge of the canopy. Use mastic to seal the joints between the frame and the brickwork.

Traditional boxed-sash windows fitted with cords and counterweights can be home-made or supplied by specialists who can also fit them for you.

Alternatively, an old vertically sliding sash window can be replaced with a new frame with spiral-balance sashes.

Remove the sashes, then take out- the old frame from inside the room. Prise off the architrave, then the window boards, and chop away the plaster as necessary. Most frames are wedged in their openings, and you can loosen one by simply hitting the sill on the outside with a heavy hammer and a wood block. Lift out the frame (1) and remove any debris from the opening.

Fit a traditional sash-window frame

Standard frames joined with posts exactly like the original, making sure the wood is treated with preserver.

Set a new spring-balance type (which has a thinner frame) centrally in the window opening. Check the frame for plumb and wedge the corners at the head and sill. Make up the space left by the old box stiles with mortared brickwork (2).

Metal brackets screwed to the new frame’s jambs can also be set in the mortar joints to secure the frame.

When the mortar has set, replaster the interior wall and replace the architrave. Glaze the sashes and apply a mastic sealant to the joints between the exterior brickwork and the frame to keep rainwater out.