How to Spot Poor Window Installation Before It’s Too Late

New windows can completely transform your home. But if they’re installed badly, they can cause nothing but headaches.

At Windows and Doors Newcastle, we’ve seen it all. Cracked plaster. Cold draughts. Even water pouring through frames during heavy rain.

The worst part? Many homeowners don’t realise something’s wrong until months later – often when it’s too late for a warranty claim.

In this guide, we’ll show you exactly how to spot poor window installation early, before it becomes a serious (and expensive) problem.

Why Proper Window Installation Matters

Even the best quality window is useless if it’s not installed correctly.

Poor installation can lead to:

• Heat loss and higher energy bills
• Mould and damp around frames
• Warped or sticking sashes
• Leaks and structural damage

At Windows and Doors Newcastle, we stress that installation is just as important as the window itself. A professional job can last decades. A botched one can start failing within months.

Early Warning Signs of Poor Window Installation

Don’t wait until winter hits or the rain starts to notice issues. Here’s what to check, even if the windows are new.

1. Draughts Around the Frame

Stand next to the window on a cold or windy day. Feel any cool air coming through the sides or bottom? That’s a red flag.

Draughts mean the window hasn’t been sealed properly. You might also feel cold spots on the surrounding walls or sill.

2. Uneven or Crooked Frames

From outside and inside, step back and check the frame. Is it level? Are the gaps even all around?

Misaligned windows may not open or close smoothly. Worse, they could shift further over time and cause cracking or sticking.

3. Windows That Stick or Don’t Close Properly

A brand new window should open and close with minimal effort. If you’re struggling to latch it shut or forcing it open, something’s off.

It could be poor levelling during installation or inadequate support underneath.

4. Gaps Between the Frame and Wall

Run your hand along the edge of the window. Can you feel or see any small gaps where the frame meets the plaster or brickwork?

You shouldn’t. There should be a neat, sealed join with no visible space. Gaps allow moisture and insects inside.

5. Water Ingress After Rain

Water on the windowsill after a storm isn’t normal. Even small leaks around the frame could mean the external sealing or drainage hasn’t been done right.

This is one of the most common complaints we hear from homeowners who didn’t use professional installers.

6. Excessive Condensation (Especially Between Panes)

Some condensation is normal. But if it forms between double glazing panes, that’s a sign of a seal failure – which may be caused by poor fitting.

You might also see water pooling at the base of the window if internal drainage channels haven’t been cleared or installed correctly.

7. Visible Damage to Surrounding Walls or Plaster

Cracks in plaster or loose paint around a new window are often signs of stress from poor alignment or frame movement.

Over time, this can lead to damp patches and even structural concerns if not fixed quickly.

What Causes Bad Window Installation?

There are many reasons, but the most common include:

• Rushed or untrained labour
• Wrong frame size used
• Poor sealing or insulation techniques
• Skipping critical steps (like using packers or level checks)
• DIY installations without experience

At Windows and Doors Newcastle, we follow a strict process for every installation to avoid these issues – including post-installation testing and cleanup.

What Should a Proper Window Installation Look Like?

A correctly installed window should:

• Sit flush and square within the opening
• Have clean, even sealant around the outside
• Open and close smoothly with no rubbing
• Show no gaps between frame and wall
• Keep your room free from draughts and leaks

If you’re unsure, compare your installation to other windows in the house. Does one feel colder? Look different? That could be your first clue.

What to Do if You Suspect a Bad Job

Don’t wait for the problem to get worse. Here’s what to do:

1. Take photos of any gaps, damage, or water ingress
2. Contact the installer and ask them to inspect their work
3. Check your warranty – most installations come with a guarantee
4. Get a second opinion from a reputable company like Windows and Doors Newcastle if you’re being ignored

In some cases, small fixes like sealing or refitting the trim can solve the issue. But severe installation faults may require the window to be removed and reinstalled.

How to Avoid Poor Installations in the First Place

Choosing the right installer is key. Here’s what to look for:

• FENSA or CERTASS registration
• A clear, written quote with no hidden costs
• Solid online reviews and local references
• A dedicated customer support team
• Full removal and disposal of old materials

At Windows and Doors Newcastle, we handle the entire process – from measurement to clean-up – using our own trained fitters, never subcontractors.

When It’s Worth Replacing the Window Entirely

If the window is leaking heavily, not closing properly, or has been installed out of square, a full replacement is often the smartest move.

It might cost more upfront, but you’ll:

• Stop ongoing damage to walls and flooring
• Regain lost heat and energy efficiency
• Improve security and resale value

We’ve helped dozens of homeowners in the North East fix these issues before they worsened – and many say they wish they’d acted sooner.

Summary: Don’t Ignore the Early Signs

Spotting poor window installation early can save you thousands in the long run. Check for gaps, draughts, and water leaks – and don’t ignore anything that feels “off”.

If something doesn’t seem right, trust your instincts and get it looked at by professionals.

If you’re in the North East and want a trusted second opinion, Windows and Doors Newcastle is here to help. We offer expert advice, honest assessments, and high-quality installations done right the first time.

Get in touch today for a no-pressure chat or free inspection.