Windows can have a dramatic effect on the appearance of your home, both from the outside and the inside. The choices range from old-fashioned windows in stained wooden frames to large single panes of glass that allow lots of natural light to flood indoors with countless variations in between.
Tools & materials required
Types of window
The part of the window that opens is called the sash and it comprises a fitted frame that either slides vertically or is hinged from one edge. Vertically-sliding windows are usually known as sash windows, while hinged windows are called casements. Although there are lots of styles to choose from, most windows are variations of these two main types. When you fit new windows, make sure you choose ones that suit the style of your house.
Casements are the most common windows. They are often a mixture of fixed panes of glass and opening casements, hinged either at the side or the top. Side-hinged casements are usually larger than the top-hinged ones. Wooden casement window frames have a vertical piece called a jamb at each side of the frame. There's also a piece called a head at the top and a sill at the bottom, all joined by mortise-and-tenon joints. The frame can be divided vertically by a piece called a mullion, or horizontally by a transom. The glazed areas of some windows are divided into smaller panes by moulded strips of wood called glazing bars. Larger windows are usually fastened with a handle and mortise plate at roughly the mid-point, and a window stay and locking peg at the bottom. Top-hinged windows could have just a window stay and locking peg. Modern window frames are sometimes fitted with ventilators, so you get a constant supply of fresh air without having to open the window.
Pivot windows are made like casement windows, but have a hinge mechanism on each side so the sash can pivot at its mid-point - which lets you clean both sides of the glass from inside your house. Special weatherproof pivot windows, double-glazed and with ventilation in the frame, can be fitted in pitched roofs. These are often used in loft conversions. Tilt-and-turn windows, which are often made to measure, open inwards at the top or might open at the side.
You'll usually find this type of window in a kitchen or bathroom. Horizontal strips of glass are attached to a frame with metal clips, and these enable the strips to pivot simultaneously to control the flow of air. On some windows you can lift the strips out of the clips, which can pose a security problem - but you can also get locking versions. Louvre windows are often fitted above or beside a fixed pane of glass.
A bay window is built into the external wall of the house, so the room extends into the bay. The frames are built to fit the shape of the wall, and the sides of each can be set at an angle of 90 degrees or less to the flat front of the house. They might be fitted with casement or sash windows. To make a curved bay, frames of equal size are set at a slight angle to each other.
Traditional sash windows slide up and down, while some modern ones slide from side to side. You operate the traditional versions with sash cords attached to cast-iron or lead weights, which are hidden in a box-like compartment inside the vertical jambs at each side of the frame. When both the top and the bottom sashes open, the window is called a double-hung sash window. The sashes are held in runners formed by the outer lining of the jambs, parting beads (which keep the sashes apart) and inner staff beads. The upper sash moves up and down in the outer runner, and the lower sash in the inner runner. They overlap at horizontal meeting rails and are held in place by fasteners screwed to the two meeting rails. Modern sash windows have spring-action spiral balances which aren't boxed in. Instead, they're set into the frame and move up and down in grooves cut in the side of the sashes.
The frames for bow windows are ready-made from a series of casements set at an angle so they form a curve. They might be fitted into a flat wall or a slightly bow-shaped one, but unlike bay windows, the curve is too shallow to extend the size of the room.
These are really doors, hinged on the side, with the bottom of the frame level with the floor.
Windows can be made of wood, plastic, steel or aluminium. These all need different amounts of maintenance.
Wooden windows look good, but they do need regular maintenance. You'll need to paint cheaper softwood windows, while hardwood and some better-quality softwood ones can be stained or painted. Modern wooden windows are often double-glazed. When you buy new wooden windows, always check they've been treated with preservative.
Plastic (or PVCu) windows are very practical and hard-wearing. They don't warp, rot or rust and are virtually maintenance free.
Steel windows have slim, welded frames which make them strong and durable. Newer ones are galvanised before they're painted, or given a polyester coating. In older ones, the galvanised coating can deteriorate - leaving them prone to rust.
You'll often find aluminium windows (usually double-glazed) in new houses. They need no maintenance unless they're fitted in a wooden frame - which will need regular painting or varnishing.
How to prepare to paint a window
You'll need to prepare the frame carefully before you begin to paint. This means stripping back any old paint and filling in any holes in the wood.
Windows are constructed using lengths of wood with grain patterns that inevitably run in different directions. So to get an even, professional-looking finish with no brush marks, you'll need to paint them in a sequence that takes account of the grain.
Also, it pays to think ahead if you're painting windows with oil-based paints as they might take longer to dry than you expect. An alternative here is to use water-based paint, which dries more quickly and gives off much less odour and fumes.
Top tip - Temporary wire stay
It's tricky to paint a window after you've removed the stay (the metal bar that holds it open). But you can make a temporary window stay using stiff wire (an old coat hanger will do the job). Cut it to the right length, and bend the ends into a small loop just large enough to drive a nail through. Then fix one end to the sill and the other to the frame using small nails.
Remove the catches and stays from the window frame before you start. If you're going to fit new window furniture after you've repainted the frame, fill the old fixing holes with wood filler and sand them smooth.
Make a temporary stay to hold the window open while you're painting it.
Prepare the surface by lightly sanding over the old paintwork using medium-grade abrasive paper.
Brush away any dust and debris, paying particular attention to the corners.
If you don't have a steady hand, use a paint shield or cut some masking tape to fit around each pane of glass. Set the tape 2mm in from the frame so the paint will just overlap onto the glass.
How to paint a casement window
For a hard-wearing finish, you'll need to use an undercoat as well as a top coat. And to seal out water you should overlap the paint onto the glass by about 2mm.
For the best result start by painting the transoms using a cutting-in brush against the glass. Next, paint the top and bottom cross rails and then the vertical mullions and jambs. Paint the edges, then the frame and lastly the sill. If you need to close the window before the paint's quite dry, rub a little talcum powder along the frame to stop it sticking.
Top tip - Keeping it straight
Not sure you can paint in a straight line? Try using a paint shield or masking tape to protect the glass. Set the tape back 2mm from the edge of the glass and take it off before the paint is dry, or the paint might lift off at the same time. Or you can use a masking pen, which leaves a layer of wax on the glass. You can take this off (along with any drips of paint) with a window scraper when the paint is dry.
Use a combined primer/undercoat to paint the frame in the sequence shown. It'll make the job easier if you use a cutting-in brush for the glazing bars.
When the first coat is dry, put the top coat on in the same sequence. Remember to keep checking there are no runs, particularly at edges and corners.
Paint the sill last. Take off the masking tape when the paint is just touch dry. When it's completely dry, you can remove the temporary wire stays.
How to paint a sash window
With a sash window, the best place to start is by painting the bottom meeting rail of the upper sash. To expose it, raise the bottom sash and lower the upper one.
Paint the vertical bars of the upper sash as far as you can. When it's touch-dry, raise the upper sash again and lower the bottom - leaving a small opening at the top and bottom.
Finish painting the upper sash, then paint the bottom sash, including the underside of the cross rail followed by the frame and the window sill. Wait until the paint is dry before you start painting the runners.
Apply a thin coat to the inner runners and the upper section of the outer runners. Try not to get paint on the cords, though - it's a good idea to pull them out of the way before you start. Carefully check that the sashes are running before your paint has dried.