The SevenDay guide on how to remove an existing window

Q – How to remove a window?

It is often assumed that changing your windows is a simple job, however there are many risks and complications that may occur along the way. Therefore, always seek expert advice or ask your SevenDay team for advice if you looking to engage in some DIY at your premise and are in any way unsure.

The following is a guide only and removal can differ depending upon the property type, age and the method of original installation.

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Removing a window is well within the reach of a competent DIYer or tradesperson, but a few things genuinely matter for safety and for the rest of the job going smoothly:

• Replacement glazing in England and Wales is covered by Building Regulations. The work must either be signed off by Building Control or carried out by an installer registered with a competent person scheme such as FENSA or CERTASS. If you remove and replace yourself, you are responsible for compliance and the certificate.
• Older windows (pre-2000) and their surrounding paint or sealant can contain asbestos or lead paint. If you suspect either, stop and get it tested before disturbing it.
• Glass and old frames are heavy and can shatter. Work with a second person wherever possible, especially above ground-floor level.
• Never lean out of or put weight on an opening you have started to dismantle, and never work at height off makeshift platforms — use proper access equipment.
• If the window is structural, unusually large, a fire-escape window, or you are at all unsure about the lintel above it, get a professional to assess it before you start.

Tools and materials you will need

Gather everything before you start so you are not hunting for tools with a half-removed window in place:

• Safety glasses, cut-resistant gloves, Kevlar sleeves (wrist cut protection) and a dust mask
• Utility knife or trimming knife
• Flat pry bar / crowbar and a wide bolster chisel
• Reciprocating saw (with metal- and wood-cutting blades) or a hacksaw and padsaw
• Cordless drill/driver and screwdrivers
• Hammer and a rubber mallet
• Old sheets, dust sheets, and strong tape (for masking and protecting glass)
• Heavy-duty rubble sacks or access to a skip
• Tape measure and a notepad (to record the structural opening size for the replacement)

Step-by-step removal

Before you remove the window – double check that your new window will fit! The removal process will often damage the old frame to an extent that it can not be re-fitted and you don’t want to be left with an exposed opening whilst waiting for a new window to be bespoke manufactured.

1. Prepare and protect the area:
   • Clear furniture away from the window and lay dust sheets across the floor and sill, inside and out.
   • Open or remove any blinds, curtains, and curtain poles.
   • If you are reusing the opening immediately, have the replacement window and fixings to hand so the opening is not left exposed longer than necessary.
2. Take out the glass and sashes first, removing the glazing before the frame makes the whole job lighter and far safer. When handling glass always ensure you wear the relevant p.p.e. (safety glasses, cut resistant gloves and kelvar sleeves to protect your wrists)
   • Opening sashes can often be unscrewed at the hinges for the sash to be removed
   • Fixed panes (uPVC and aluminium): remove the internal glazing beads. Slide a stiff putty knife or bolster into the joint between bead and frame and gently lever — the beads usually unclip. Start with a long edge, then the short edges.. Ensure care is taken when de-beading as glass as it can easily be broken. Lift the sealed glass unit out from the bottom, keeping it vertical. It is heavy — have a helper take the weight. Set it down on a soft edge, leaning against a wall, well out of the work zone.
   • Fixed panes (for timber windows with putty-glazed panes): score around the putty, chip it out with a chisel, remove the glazing sprigs or pins, and lift the pane free. If the pane is already cracked, tape it in a criss-cross pattern first to hold the shards together.
3. Release the frame fixings, look around the inside of the frame for fixing screws, usually hidden under trims or plastic caps, set into the jambs (the vertical sides). Unscrew all that you find. Some more recently installed uPVC frames may have been installed with “straps” – you will not see screws inside the frame for this method or original installation.
   • Older frames may be held with metal lugs or nails driven into the brickwork rather than screws. These will need to be cut. Some uPVC frames may have been installed with “straps” – you will not see screws inside the frame for this method or original installation. In this instance the strap location will need to be established and either the internal plaster reveal removed to release the strap, or cut the frame and jammy to get to the strap fixing on the external frame edge. Straps are normally fitted every 30cm as a guide.
4. Run a utility knife around the full perimeter where the frame meets the plaster inside and the render or brick outside, cutting through paint, sealant, and silicone that may be between the frame and the house wall. This breaks the bond and protects the surrounding finish from tearing.
5. Cut through stubborn fixings, where screws will not come out or the frame is held by lugs or nails, cut through the fixings with a reciprocating saw fitted with a metal-cutting blade. Slide the blade into the gap between the frame and the masonry and cut through anything bridging the two.
6. On a uPVC or timber frame you can also make a vertical cut through one of the frame members (a transom or mullion) to collapse the frame inward, which makes it much easier to lever the pieces out. Keep the blade clear of the surrounding wall.
7. Lever out the frame, Working from the inside, insert the pry bar between the frame and the wall at a fixing point. Lever gently and evenly, working around the frame rather than forcing one corner. [tip] Protect the surrounding plaster and brick with a scrap of timber behind the pry bar to spread the load and prevent damage to the brickwork.
8. Once the frame is loose, work it free and lift it clear. With larger frames, cut them into sections first so they can be removed in manageable pieces.
9. Clean up the opening, remove all old fixings, nails, lug remnants, and offcuts of sealant or expanding foam from the reveal. Knock back any loose mortar or plaster, and check the condition of the lintel above and the sill below. Rotten timber, cracked stone sills, or a failing lintel must be dealt with before a new window goes in. Brush out the opening so it is clean and dry, ready for the new frame.

Disposing of the old window

Old frames and glass should not go in your household bin. Options include:

• A hire skip, or your contractor’s skip if you have one on site. If you purchased your new window from SevenDay you can use our skip for FREE to dispose of your old window safely
• Your local household waste recycling centre — glass and uPVC are often accepted separately. uPVC frames are recyclable; if returned to SevenDay we will ensure your frame is sent to be fully recycled, alternatively many trade suppliers and recyclers will take them 

Common mistakes to avoid

• Leaving the glass in the frame — it makes the unit heavy, awkward, and dangerous to handle.
• Forcing a single corner with the pry bar, which cracks the surrounding plaster or render. Work evenly around the frame.
• Cutting blindly with a reciprocating saw near cables or pipes — check what runs near the reveal first.
• Not measuring the opening before ordering the replacement, or measuring the old frame rather than the structural opening.
• Leaving an opening exposed overnight in bad weather or for security — board it up if the replacement is not going straight in.

This guide covers a standard domestic window. Bay windows, structural openings, and anything load-bearing or unusually large are a different job and are best handled by, or checked with, a professional installer.