Glazing Doors and Windows

A broken window is probably one of the most inconvenient things which can happen at home.

It can also be dangerous because of broken and jagged pieces of glass, so should be quickly repaired; this is not a difficult task. Updating your glazing can bring more light into your home and give an opportunity to make use of some of the many interesting coloured and textured glasses which are made.

Glaring work is best carried out in warmer weather, as at lower temperatures glass becomes brittle. Avoid/using old glass; this turns brittle with age, is difficult to cut satisfactorily and will tend to break.

Situations requiring glazing attention are door or window repairs or replacement, improvements where an ordinary clear glass is replaced by a patterned or textured glass, or where a timber door is replaced by complete glass or glass-panelled door, to let in more light.

In some cases it is advisable to remove frames, when glazing or reglazing, for safety or access reasons.

Wood frames

Glass is held in a channel called a rebate, usually with putty and special pins, called sprigs, but sometimes with panel pins. When handling glass, always wear thick protective gloves. Apart from the danger of injury from slivers of broken glass, new glass may have sharp edges.


You will need a glazier’s hacking knife, or an old screwdriver, to remove the existing glass, a pair of pincers, to pull out glazing sprigs, and a Warrington-pattern hammer with a cross-pein head.


An intact pane can, with care, be removed undamaged, though this is more difficult to do in cold weather or when glass is old. Work from the top of the frame down- wards when removing glass. First, loosen all the putty around the outside edge of the glass with the hacking knife. This will expose the sprigs or pins; these can be carefully pulled out with the pincers. Eventually the pane, or remnants, can be lifted out. Take care, however, that the glass does not fall out and shatter.

Old, hardened putty may have to be hacked out with a hammer and chisel. Any segments of glass remaining in the rebate can be prised out with pliers.

Next, remove all old putty down to the bare wood. Clean the rebate with medium glasspaper, apply a coat of wood primer and allow to dry. Drying takes about four hours.

Measure the rebate with a steel tape, from the inside edge of each rebate, taking each side top and bottom separately and then measure across the two diagonals. These measurements should be equal if the frame is square.

Glass must be cut slightly undersize to allow for expansion. For sheets of average size, allow around 1.5mm, but twice this where the pane is more than 370mm2 in area.

Once you have cut the glass, it is wise to remove sharp edges with an oilstone lubricated with water, oil, turpentine or white spirit. So that the glass fits accurately in the frame, mark the outer face side; a wax pencil or crayon can be used.

Standard putty is used for glazing timber frames. A non-hardening mastic should be used when fitting sealed double-glazed units or glazing metal frames.


Roll the putty in the hands until it is soft and easy to work. If putty is too oily, it can be wrapped in newspaper to absorb the oil. Linseed oil can be added to standard glazing putty to soften it. Once the consistency is correct, lay a 3mm thick strip of putty, called the bedding putty, into the back of the rebate with the thumb.

Place the glass in the rebate. Set this in from the bottom, leaving an equal space on each side, and press the glass, firmly at the sides, into position against the putty; never press glass from the centre.

Press evenly around the edges until all surplus putty is squeezed out, leaving about 1-5mm between the back of the glass and rebate. Cut off excess putty with the putty knife.

Fix the glass into place by tacking the sprigs or pins into the frame, parallel with the face of the glass. Start the pins with the cross-pein head of the hammer. Keep the side of the hammer parallel with the face of the glass and on it while fixing; this will avoid hitting the glass and, possibly, cracking it. Space the sprigs at intervals of about 150mm.

A strip of weathering putty should now be evenly applied at an angle on the outside of the rebate.

Smooth the putty with the putty knife, keeping this lubricated with water to prevent putty from sticking to the blade. Hold the blade in one corner against the rebate, with the tip resting at an angle of about 45° on the glass, and draw the blade smoothly downwards.

This angle is important as it allows rain to run off and not collect. Trim away excess putty with an even pressure of the knife. Trim each area with one stroke to ensure a clean surface line. Make a neat mitre at each corner. Finally, go over all the putty surfaces with a damp, soft brush.

Allow two or three weeks to elapse and then paint over the putty with an oil undercoat and then a finishing coat to match surrounding paintwork. Allow paint slightly to encroach, by about 3mm, on to the surface of the glass, to seal the join.

10. November 2011 by admin
Categories: Featured, Handyman Tips | Tags: , , , , , , , , , | Comments Off on Glazing Doors and Windows


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