How to remove a window: A safe step-by-step guide

To remove a window, take out the glass and any opening sashes first, then cut through the sealant and the fixings holding the frame to the wall. Saw the frame in two so it releases without levering against the brickwork. Order the replacement before you start, and notify Building Control.

Key takeaways

Measure and order the new window before you remove the old one. The opening is not the window size.
Replacing a window is notifiable work under Building Regulations. Doing it yourself means notifying Building Control yourself.
Take the glass out before the frame. A glazed frame is heavy, sharp and awkward.
Cut the frame rather than levering it. Levering damages the reveal you have to seal against afterwards.
Toughened and laminated glass are not accepted in ordinary recycling. Check before you load the car.

Do you need permission to remove and replace a window?

Yes, in almost every case. Since April 2002, replacement glazing in England and Wales falls under the Building Regulations, which makes replacing a window notifiable work. Swapping a failed sealed unit while keeping the frame is the exception and needs no notification.

There are two routes to compliance, and which one applies depends on who does the work:

A FENSA or CERTASS registered installer self-certifies the job and registers it with your local authority. You receive a certificate.
Anyone else, including you doing it yourself, has to submit a building notice to your local authority Building Control before starting, and let them inspect and sign off.

The responsibility sits with you as the homeowner either way. Replacement windows have to satisfy Part L for energy efficiency, Part F for ventilation, Part K for protection from falling and the safety glazing requirements, so Building Control will want to see that the new window meets them.

That certificate matters later rather than now. When you sell, the buyer's solicitor will ask for proof of compliance for any window fitted since 2002. Without it you are looking at retrospective approval or indemnity insurance, and either can hold up a sale.

Some properties sit outside the self-certification route altogether. Listed buildings, conservation areas and homes under an Article 4 direction may need planning permission as well, even for a like-for-like replacement. Check those before you order anything.

How do you remove a window, step by step?

Measure and order the replacement before you remove anything.
Notify Building Control, or book a registered installer.
Take out the glazing beads and lift the glass clear.
Unscrew the hinges and lift off any opening sashes.
Cut the sealant around the frame, inside and out.
Cut or unscrew the fixings holding the frame to the wall.
Saw through the frame at two points and release it.
Check the opening for rot, damp and a sound lintel.

The order matters more than the technique. Glass first, sashes second, fixings third, frame last. Each step makes the next one lighter, and a frame that still holds glass is heavy enough to pull someone off balance when it finally releases.

Step seven is the one people skip. Cutting the frame in two or three places lets each piece come away on its own, with no leverage against the brickwork. Levering a whole frame out in one piece is how reveals get cracked and plaster gets pulled off inside, and you then repair that before you can seal the new window.

See our selection of windows here

What should you do before you start?

A reciprocating saw or a multi-tool with a metal-cutting blade, for the fixings and the frame.
A stiff utility knife or a sealant remover for the perimeter joint.
A pry bar and a bolster chisel, used sparingly.
A cordless drill or driver for the frame screws.
Suction cups for handling glass, or heavy-duty gloves at a minimum.
Safety glasses, cut-resistant gloves and steel-toe boots.
Dust sheets, and a board cut to fit the opening if the job runs over.

The reciprocating saw is what separates this job from a struggle. Frame fixings are often screwed through the frame into the brickwork and seized after twenty years. Cutting them takes seconds. Trying to reverse them out takes an afternoon and usually ends in cut fixings anyway.

What tools do you need?

Glas in der Haustür wirft beim Thema Sicherheit Fragen auf, denn eine Glasfläche könnte eingeschlagen werden. Auch hier gibt es gute Lösungen.

An gefährdeten Stellen, besonders wenn Glas in Reichweite des Schlosses sitzt, ist Sicherheitsglas sinnvoll. Verbundsicherheitsglas (VSG) besteht aus mehreren Scheiben mit einer reißfesten Folie, an der die Splitter bei Bruch haften, sodass kein durchgreifbares Loch entsteht.

So bleibt der Lichtgewinn erhalten, ohne dass das Glas zur Schwachstelle wird. Glas und Beschläge sollten dabei zusammen betrachtet werden. Unsere Türen entsprechen den aktuellen Anforderungen an die Sicherheit; mehr dazu im Ratgeber zum Sichern der Haustür.

How do you remove a uPVC window frame?

Start with the glazing beads. Slide a stiff knife into the gap between the bead and the frame, work along until the bead lifts, and pull it away by hand. Keep the beads in the order they came off, because they are cut to length and the lengths differ.

Leave the top bead until last. It holds the glass in place while you free the other three sides, and it is what stops a pane tipping into the room when you do not have a hand on it.

With the glass out and the sashes unscrewed from their hinges, you are left with an outer frame fixed to the brickwork. Those fixings sit behind the frame face, usually through the jambs at intervals up each side.

Cut them with the reciprocating saw rather than hunting for screw heads.

uPVC frames have a steel reinforcement section running inside the profile, so use a blade that handles metal and expect the cut to be slower than it looks. Once the frame is cut at two points, each section pulls inward and away from the reveal.

How do you remove a timber window frame?

The glass comes out the same way, except that on an older timber window it is bedded in putty rather than held by beads. Rake the putty out, pull the glazing sprigs with pincers, and the pane lifts free. Expect the putty to be hard and the job to be slower than it sounds.

Timber frames are more likely to be built into the brickwork rather than screwed to it. Look for frame cramps, which are metal straps fixed into the mortar joints. They will not unscrew, so cut them.

Be careful with the cill on a timber window. It often extends beyond the frame into the brickwork on both sides, and cutting the frame without freeing the cill ends first will split the reveal.

How do you check and prepare the opening?

Once the frame is out, you can see what has been hiding behind it for twenty years. Probe the timber of any remaining sub-frame or cill with a bradawl, look for damp staining on the inner reveal, and check the underside of the lintel for cracking or sagging.

Brush the opening out and take the old sealant and mortar snots off both faces. The new window seals against these surfaces, so anything left behind becomes a gap later. Our guide to resealing windows explains what that joint has to do.

Then measure the opening properly, in three places across the width and three up the height, and work to the smallest of each. Openings are rarely square and rarely consistent. The installation guide covers the fitting tolerance the new frame needs.

How do you get rid of the old window and glass?

Toughened and laminated glass are not accepted in ordinary household glass recycling. They are made differently from bottle glass and they contaminate the stream. Take them to a household waste recycling centre and tell the site staff what you are bringing.

uPVC frames are recyclable, but not through kerbside collection. Many recycling centres take them as rigid plastic, and some window installers take old frames back. Ring ahead rather than turning up with a car full of frame sections.

If you are having the new windows fitted by an installer, removal and disposal is usually part of the job. That is worth pricing in before you decide to do it yourself, because two trips to the tip with glass in the back of a car is a real cost in time.

When should you not do this yourself?

There are jobs where the answer is to stop and call someone, and they are not always the ones that look hardest. Four cases:

The wall above the window is load-bearing and there is no lintel, or the lintel is cracked.
The window is above ground-floor level and cannot be reached safely from inside.
The property is listed, in a conservation area, or under an Article 4 direction.
The window is a fire escape from a bedroom or loft room and you are not certain the replacement keeps the required opening.

The Building Control route is also worth pricing against the alternative. A registered installer self-certifies the work, handles the notification and gives you the certificate, and the removal and disposal come with it. Doing it yourself means the building notice, the inspection and the tip runs are all yours.

If the outcome is a new window either way, the honest comparison is your weekend and the paperwork against the difference in price. Our uPVC and timber windows carry a 10-year full warranty and are UKCA marked, and when to replace your windows covers whether the old ones have earned it.