Does house insurance cover blown windows?

House insurance will protect you against sudden external factors which affect your property. Blown windows can be a result of poor installation, which is why it's essential you contract someone from the Competent Person Scheme if you already own the property or ask for a FENSA certificate if you're buying. Both options will insure you in the event of poorly fitted windows.

Can failed double glazing cause mould?

Yes, it can. Although there are temporary fixes to your condensation problem, you will most likely need to get the seal or even the windows replaced. This can be an extra cost and burden, which you may not want to deal with when you buy a property. Not dealing with this can cause damp and subsequently mould issues to arise.

Does condensation on windows mean they need to be replaced?

If you notice condensation on your windows, this is usually a sign of blown windows. You could also start to experience heat loss through double glazing windows. You will need professional help to replace the sealant in between the glass panes or the windows.

Can blown windows cause damp? SAM Conveyancing explains how to spot the signs

This can lead to condensation, damp and ultimately mould problems. Dealing with this is an extra cost you'll want to avoid.

An experienced surveyor will be able to uncover these for you. All our fees are fixed and we offer same week availability, with arranged access.

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Can Blown Windows Cause Damp?

by:

Andrew Boast

Last Updated: 10/06/2026

Read by:

2,274

5 min read

Key Takeaways

Double glazed windows are more efficient in terms of heat retention.
Condensation is often formed on single glazed windows, although they can also show up on double glazed ones. This is often a sign of blown windows.
You can temporarily fix the problem, but in most cases you will need to replace the sealant or the actual windows.
When buying a house, your Level 2 and Level 3 surveys will check for damp and any signs of double glazing failure.

When buying a house, it is essential you check for any potential risks to your investment. Factors like whether your windows are single glazed or double glazed can affect you once you move in. Single glazed windows are really common in a lot of properties throughout the UK, but they are less efficient in terms of heat retention and they are often affected by condensation.

Double glazed windows, however, keep you home warmer during the winter and cooler during the summers. Double glazed means that your windows are made out of two panes of glass, separated by a spacer bar.

An air gap is created in between the two panes, which prevents heat loss through double glazing windows. Although they are believed to be more efficient, the sealant in between those panes can be damaged, which leads to what is known as 'blown windows'.

Do blown windows cause condensation?

Yes, condensation is the biggest indicator of blown double glazed windows. As a result, windows tend to become foggy or cloudy. This is caused by a gap forming in between the panes, caused by either a damaged sealant or a defect to the actual glass panes.

So, can blown windows cause damp? If left untreated, yes, the condensation can lead to damp and even mould problems.

How do you tell if a double glazed window is blown?

Condensation
Rotten window frame
Draught
Water seeping through the frame

Signs of double glazing failure may not always be visible. For example, in the summertime, sellers can try to hide damp problems or they can paint over mould/damp affected areas. We always recommend getting a surveyor to check for this issue, as they are trained to recognise signs of blown double glazed windows.

Your level 2 or level 3 survey should uncover this. We discuss the difference between the two in our article - What Is The Difference Between Level 2 and Level 3 Survey?

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Are blown windows a problem?

Blown windows are a problem, as they can cause condensation. If left untreated, this can lead to damp and mould forming inside the property, which is toxic for you and your family.

Another factor you need to weigh in is heat loss through double glazing windows. Whether or not can blown windows cause damp, an increased energy bill is something you'll want to avoid, especially in the cost of living crisis.

An indicator that windows can cause problems in the future is the absence of a FENSA certificate. Windows which have been replaced after April 2002 require it, as this attests that the work has been carried out by a member of the Competent Persons Scheme, and therefore it complies with all Building Regulations.

If the sellers chose to replace the windows themselves, they will not be able to provide you with this, so you should make sure that the work is still compliant. The best way to know if there's cause for concern is to get an experienced surveyor to check. They will be able to identify any possible risks.

How do you tell if a house has a damp problem?

Damaged internal decoration – Damp or discoloured tidemarks on internal walls;
Damaged plaster – Disintegration, salting or blistering;
Rotting skirting boards or floor boards – wet rot with decay;
Localised dampness – Dampness on walls rarely exceeds one metre above ground level, but may go much higher in extreme cases

If you suspect you have a damp problem, you can get a damp and timber survey to check. If that is the case and the problem is severe, you will need to act fast, as this can devalue your property.

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Written by: Andrew Boast

Andrew Boast FMAAT is a qualified accountant, conveyancing specialist and author with over 25 years of experience in the UK property sector. Since beginning his career in 2000 within established SRA and CLC-regulated conveyancing solicitor firms, Andrew has overseen the legal journeys of more than 75,000 clients.

He is the self-published author of the first-time buyer guide: How to Buy a House Without Killing Anyone, and a frequent contributor to mainstream UK media on legislative updates, property law, first-time buyer guides, conveyancing best practices, and stamp duty changes. Andrew specialises in resolving complex title issues, property conflict disputes, and property tax options, streamlining the enquiry process to reduce transaction times and maintaining a client-friendly focus.

Reviewed by: Amanda Ambler

Amanda Ambler is a highly accomplished conveyancing specialist with over 15 years of dedicated experience across residential property law, legal compliance, and practice management. Having held senior roles, including Head of Legal Practice and Head of Conveyancing at established UK law firms, Amanda possesses a profound, hands-on understanding of the technical intricacies of the property market.

As the designated Legal Content Reviewer for SAM Conveyancing, Amanda ensures that every guide, legal update, and resource published meets the absolute highest standards of accuracy, regulatory compliance, and factual integrity. Her rigorous review process guarantees that complex property legislation and industry processes are communicated clearly, transparently, and safely for home buyers and sellers alike.

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