Cracked, broken or misted sash glass is a straightforward fix in most cases. We offer 4mm clear, 6.4mm safety laminate and sandblasted or satin glass as standards, and we can supply any glass in the Pilkington range. We quote free after a visit.
When glass needs replacing
The obvious reason is a crack or a break. A crack can spread with temperature changes, so it is wise to replace the pane soon. Meanwhile, a broken pane lets in rain and cold air.
There are other reasons too. For example, old putty may have failed, so the glass rattles in its bars. Or you may want privacy glass for a bathroom, or tougher glass for a lower window. In each case, the glass and the putty need attention together.
If rattling is your main worry, our guide on why sash windows rattle explains the usual causes. Loose glass is only one of them, since beads and cords matter too.
The glass we offer
We keep the choices clear because each standard suits a different need. We explain the differences in plain terms.
First, 4mm clear glass is the plain option, and it suits most single-glazed sashes. Second, 6.4mm safety laminate holds together if it breaks, so it suits low windows or rooms near doors. Third, sandblasted or satin glass gives privacy while still letting light in.
In addition, we can supply any glass in the Pilkington range. That includes low-E glass, which helps keep heat in. If you want something specific, tell us at the visit and we will check what is available.
Replacing a single pane
We replace most single panes without removing the whole sash. We cut out the broken glass and clean the rebate. Then we bed in the new pane and finish it with fresh putty or bead.
Next, the putty needs time to skin over before it takes paint. So we prime it and leave the window ready for decorating. If the glazing bars are rotten, we repair them first, because new glass will not last in damaged timber. Our sash window repairs page covers that work.
Single glazing or double glazing
Replacing a pane like for like keeps the window single glazed. For many owners that is fine. However, if the window is draughty or cold, a different upgrade may help more.
Often the best step, if the glass is misted, is to double glaze your existing sash windows. We rebate the sash more deeply to hold a sealed unit. The unit uses Pilkington low-E glass and carries a five-year guarantee.
Slimmer alternatives also exist. For example, our article on slim double glazing versus vacuum glazing compares them in plain terms. It helps you decide before you spend.
Putty, beads and fixing
Good glass needs a good seal. We bed each pane in putty or bead so that it sits firmly and keeps the rain out. Then we check that the sash still slides freely, because heavier glass can upset the balance.
However, if the new glass is much heavier, the weights may need adjusting. In that case, we tell you at the quote stage. That way the sash still opens and stays where you leave it.
Do you need new glass at all?
Sometimes glass is not the problem. Draughts usually come from the gaps around the sashes, not through the glass. So draught proofing may do more for comfort than new panes.
Our guide to draught proofing versus secondary glazing sets out what each option fixes. Many homes do best with draught proofing first, then glazing changes if needed.
Cost
Glass work is priced to the job, because pane size, glass type and the condition of the bars all vary. We therefore quote in writing after a free visit. For known rates on related work, see our costs page.
For example, a small splice repair is £80 and a bottom-rail repair is £120. We include these in the quote when glass and timber need work together.
Listed and conservation homes
Original glass matters on listed buildings. We handle listed and conservation work case by case, so we check the rules with you first. Our page on listed building sash windows explains how we approach it.
What to do next
If a pane is broken, cover it and keep the area clear until we arrive, because loose shards are sharp. We then visit, measure and quote at no charge. Our guarantee lasts five years on labour.
To start, send us your postcode and a photo. We cover all Greater London postcodes. We are open Monday to Friday, 08:00 to 18:00.