The Window Snag Checklist for New-Build Homes

Why Windows Need Their Own Checklist

Windows are the most common source of draughts and weather-tightness complaints in new homes. A frame that is not sealed, a sash that catches, or a trickle vent fitted the wrong way will all affect comfort and energy bills — and most are quick to put right while the installer is still on site. A window-specific checklist makes sure you test every opening light and feel for draughts rather than just looking through the glass.

Use this with the full new build snagging checklist.

How to Inspect Windows

Open and close every opening window — the feel tells you more than the look. Run your hand around the frame when closed to feel for draughts, and check the seal between frame and wall externally where you can reach. Check glazing for defects in good natural light, viewed at an angle.

What to Check

Frames and glazing

• Frames are square, level and securely fixed with no movement.
• No scratches, cracks or damage to frame or glazing.
• Double glazing has no condensation or misting between the panes.
• Glazing beads are fitted cleanly with no gaps.
• External seal between frame and wall is continuous.

Operation and hardware

• Every opening sash opens and closes smoothly and latches cleanly.
• Handles are secure and operate without force.
• Locks engage and release correctly.
• Hinges are adjusted so sashes do not drop or catch.
• Friction stays hold the sash open at any position.

Seals, draughts and drainage

• No draughts felt around the closed frame.
• Weather seals are continuous and not pinched or folded.
• Trickle vents (if fitted) open, close and are the right way up.
• Frame drainage (weep holes) are clear and not blocked.
• No water trapped in the frame after rain.

Common Window Defects

The most common window defects are sashes that catch or drop, draughty frames where the external seal is incomplete, blocked weep holes that let water sit in the frame, and misted double-glazed units (a sealed-unit failure). Mist between the panes is a defect that will be replaced under warranty — photograph it early, as it can come and go with temperature.

For the wider set of defects, see common new build defects. For the standards that cover windows, see the NHBC standards guide.

Window Snag Checklist

Work through each section, tick items off as you check them, and export a clean printable PDF to take with you on the day.

Frequently Asked Questions