5 Common Window and Door Fitter Problems and When to Call a Professional

The problems that come up most

These are the jobs window and door fitters are most commonly booked for. Catching them early almost always costs less:

• misted double glazing where the seal has failed
• draughts around frames
• doors dropping and catching
• condensation between panes
• broken handles, hinges and locks

What you can safely check yourself

Before calling anyone, gather information: when the problem started, whether it's getting worse, and clear photos. This helps a professional give you a realistic first assessment and helps you describe the job accurately when collecting quotes.

Basic observation is always safe; DIY repair is not always. If the problem involves gas, electrics, working at height or the structure of your home, stop at observation and call a professional.

Signs it's time to book someone

Book a professional when the problem is getting worse, when it involves safety, when your own attempts haven't held, or when you simply don't know the cause. A correct diagnosis is usually cheaper than a wrong repair.

For context on cost: Supply-and-fit uPVC windows typically cost £400–£700 per window; a full house of windows runs £4,000–£8,000. Composite doors usually cost £900–£1,500 fitted.

Choosing who to call

FENSA or CERTASS-registered installers can self-certify that replacement windows and doors meet Building Regulations and issue the certificate you need when selling your home. Check the company on the scheme's own register.

Check recent reviews before booking — Hammerscore company pages for window and door fitters combine ratings from several platforms, and the low-star reviews tell you most about how problems were handled.