Old Window Putty Could Be Hiding a Serious Asbestos Risk
Cracked, crumbling putty around your windows might look like a minor maintenance issue. But in buildings constructed before the 1980s, that deteriorating sealant could contain asbestos fibres — and once disturbed, those fibres become airborne and pose a genuine threat to health.
Asbestos window putty glazing is one of the less well-known hazards lurking in older UK properties, yet it affects schools, offices, factories, and homes across the country. Knowing where asbestos was used in glazing, how to identify it, and what to do about it could protect the health of everyone who uses your building.
Why Asbestos Was Added to Window Putty and Glazing Compounds
Before asbestos was banned in the UK, it was considered a wonder material. It was cheap, durable, fire-resistant, and could be blended into almost any product — including window putty and glazing compounds.
Asbestos fibres — most commonly chrysotile (white asbestos), but sometimes crocidolite (blue asbestos) — were mixed into putty to give it extra strength, improve resistance to heat and moisture, and help it maintain a watertight seal around glass panes. The result was a product that performed well in the short term but left a lasting legacy of risk.
Single-Glazed Windows and Wooden Frames
Single-glazed windows installed before the 1980s are among the most likely places to find asbestos-containing putty. Wooden-framed windows in schools, council buildings, factories, and older domestic properties were frequently sealed with asbestos-reinforced compounds during installation.
Box sash windows, greenhouse glazing, and skylights were also common applications. If your building dates from before 1985 and still has its original glazing, there is a real possibility that asbestos putty or caulking remains in place — even if it looks intact from the outside.
Industrial Buildings and Commercial Properties
Industrial sites relied heavily on asbestos-containing materials throughout the mid-twentieth century. Glaziers working on factories, warehouses, and commercial premises routinely handled asbestos putty as a standard part of the job.
In some cases, blue asbestos was used alongside white asbestos in industrial glazing applications, which carries an even higher level of risk. If you manage an older commercial or industrial property, original putty or caulking may still be present in window joints, along sills, and in the rebates where glass meets frame.
Past repairs can also leave fibres trapped in layers of overpainted sealant that looks perfectly stable. Never assume a repainted or patched surface means the hazard has been dealt with.
How Asbestos Fibres Are Released from Window Putty
Intact, well-bonded asbestos putty that has not been disturbed presents a lower immediate risk. The danger rises significantly when the material begins to deteriorate or is disturbed by maintenance work.
Natural Weathering and Ageing
Putty exposed to the elements does not last forever. Sun, rain, frost, and wind gradually break down the binder, causing the material to shrink, crack, and become brittle.
This process — known as becoming friable — means the putty can crumble at the lightest touch, releasing microscopic asbestos fibres into the surrounding air. Once airborne, these fibres are invisible to the naked eye and can remain suspended in the air for hours. Anyone in the vicinity — residents, maintenance staff, or contractors — may inhale them without realising it.
Repair and Maintenance Work
Scraping, sanding, chiselling, or using power tools on old window putty dramatically increases fibre release. Even seemingly minor tasks — repainting window frames, replacing a cracked pane, or applying fresh sealant over old material — can disturb asbestos-containing putty and create a serious exposure risk.
Quick fixes such as applying insulating tape over cracked areas do not prevent fibre release if the underlying material is already damaged. They simply delay the problem while the putty continues to deteriorate beneath the surface.
Health Risks Associated with Asbestos Exposure
The health consequences of inhaling asbestos fibres are well-established and serious. What makes asbestos particularly dangerous is the long latency period between exposure and the onset of disease — symptoms may not appear for anywhere between 10 and 50 years after initial exposure.
Asbestos-Related Diseases
Prolonged or repeated inhalation of asbestos fibres can lead to a range of serious conditions, including:
- Mesothelioma — a cancer of the lining of the lungs or abdomen, almost exclusively caused by asbestos exposure
- Lung cancer — risk is significantly elevated in those with a history of asbestos exposure, particularly smokers
- Asbestosis — a chronic scarring of the lung tissue that causes progressive breathlessness
- Pleural thickening — a thickening of the membrane surrounding the lungs, which can restrict breathing
Common early symptoms include a persistent cough, chest tightness, and shortness of breath. These are easy to attribute to other causes, which is why many people do not seek medical advice until the disease is well advanced.
Who Is Most at Risk?
Construction workers, glaziers, and maintenance staff who worked with asbestos-containing materials between the 1950s and late 1990s faced the highest historical exposure. But the risk does not end there.
Today, property managers, facilities staff, and tradespeople carrying out refurbishment work on older buildings face ongoing exposure risk if asbestos-containing materials are not identified and managed properly. Homeowners undertaking DIY repairs on older properties are also vulnerable, particularly if they are unaware of the potential hazard in their window putty.
How to Identify Asbestos Window Putty Glazing in Your Property
You cannot identify asbestos by looking at it. Asbestos fibres are microscopic, and asbestos-containing putty looks no different from putty that does not contain asbestos. However, there are visual signs that should prompt you to arrange professional testing before any work takes place.
Visual Warning Signs
If your building was constructed before 2000 — and particularly before 1980 — treat any deteriorating window putty with caution. Specific signs to look out for include:
- Putty that is crumbling, powdery, or breaking away from the frame
- Gaps appearing between the glass and the frame
- Brittle material that fractures under light pressure
- Discolouration or surface cracking across the sealant
- Evidence of previous repairs using tape or filler over original putty
Do not attempt to touch, scrape, or sample the material yourself. Even a small disturbance can release fibres. Keep the area clear and arrange a professional inspection.
Professional Asbestos Testing
The only way to confirm whether window putty contains asbestos is through laboratory analysis of a sample collected by a trained surveyor. Supernova Asbestos Surveys provides professional asbestos testing services across the UK, carried out by qualified surveyors who follow HSE guidance and the requirements of the Control of Asbestos Regulations.
Surveyors collect bulk samples safely, minimising disturbance and fibre release during the process. Samples are then submitted for sample analysis at an accredited laboratory, and you receive a written report confirming the findings. Do not rely on a visual assessment alone — risk remains even when putty appears intact.
What UK Regulations Say About Asbestos in Buildings
The Control of Asbestos Regulations place clear legal duties on those responsible for non-domestic premises. The duty to manage asbestos requires dutyholders to identify asbestos-containing materials, assess their condition, and put in place a management plan to prevent exposure.
HSG264, the HSE’s guidance document on asbestos surveys, sets out how surveys should be conducted and what information they must provide. This applies directly to scenarios involving asbestos window putty glazing, where the material may be present in areas that are routinely accessed or maintained.
Management Surveys and Refurbishment Surveys
For occupied buildings, a management survey is the standard starting point. It identifies the location and condition of asbestos-containing materials that could be disturbed during normal occupation and routine maintenance — including window putty and glazing compounds.
If you are planning refurbishment work on an older building, a refurbishment survey is required before work begins. This goes deeper than a management survey and covers areas such as window frames and glazing that may not be fully accessible during routine inspection.
Where a building is to be demolished entirely, a demolition survey is required. This is the most intrusive type of survey and must be completed in full before any demolition work starts.
Legal Consequences of Non-Compliance
Failure to commission the correct survey before work starts is a breach of the regulations. Failure to manage asbestos properly is a criminal offence.
Dutyholders — including landlords, employers, and building owners — can face prosecution, significant fines, and civil liability if workers or occupants are exposed to asbestos as a result of inadequate management. The regulations apply to all non-domestic premises, and the duty to manage extends to common areas of residential buildings such as blocks of flats.
Safe Handling and Removal of Asbestos-Containing Window Putty
If testing confirms that your window putty contains asbestos, the next step is to determine the appropriate course of action based on the condition of the material and any planned works.
Managing Asbestos in Place
Not all asbestos-containing materials need to be removed immediately. If the putty is in good condition and is not going to be disturbed, it may be appropriate to manage it in place — monitoring its condition regularly and updating your asbestos register accordingly. This approach requires professional assessment and must be documented properly.
Regular monitoring is essential. If the condition of the material changes — if it begins to crack, crumble, or shows signs of deterioration — you will need to reassess whether removal has become necessary.
When Removal Is Required
If the putty is deteriorating, if repair or refurbishment work is planned, or if the material poses an ongoing risk, asbestos removal will be necessary. This work must be carried out by licensed contractors for certain types of asbestos work, in accordance with the Control of Asbestos Regulations.
The key steps during safe removal include:
- Checking the asbestos register and management plan before any work begins
- Engaging a licensed asbestos removal contractor where required by law
- Setting up appropriate containment to prevent fibre spread
- Using hand tools where possible to minimise dust generation
- Keeping materials damp during removal to suppress fibre release
- Using approved respiratory protective equipment and disposable overalls
- Cleaning the work area with damp cloths or a vacuum fitted with a HEPA filter — never a standard household vacuum
- Double-bagging and labelling all asbestos waste for disposal at a licensed facility
Never attempt to remove asbestos-containing window putty yourself. The risks of self-removal are significant, and improper handling can result in widespread contamination of the surrounding area.
Practical Steps for Property Managers and Building Owners
If you manage or own a building constructed before 2000, the following checklist will help you manage the risk from asbestos window putty glazing effectively.
- Check your asbestos register. Does it include an assessment of window putty and glazing compounds? If not, it may be incomplete and should be reviewed by a qualified surveyor.
- Commission a survey if you don’t have one. A management survey will identify the presence and condition of asbestos-containing materials, including glazing compounds, across your building.
- Brief your maintenance team. Anyone carrying out routine repairs — window cleaning, repainting, resealing — needs to know that asbestos putty may be present and must not disturb it without proper assessment.
- Do not allow uncontrolled work on windows. Before any contractor touches window frames, putty, or glazing in a pre-2000 building, confirm whether the material has been tested. If not, arrange testing first.
- Review your asbestos management plan regularly. If the condition of putty changes, your plan must reflect that. Static registers that are never updated create legal and safety risks.
- Arrange removal when the time is right. If you are planning a window replacement programme or any refurbishment involving glazing, commission the appropriate survey first and factor asbestos removal into your project timeline and budget.
Asbestos Window Putty Across the UK: Where We Work
Asbestos-containing glazing materials are found in older buildings across every region of the UK. Supernova Asbestos Surveys operates nationwide, with specialist teams covering major cities and surrounding areas.
If you need an asbestos survey in London, our teams cover the full capital and surrounding counties. For those in the north-west, we provide a full asbestos survey in Manchester and the wider region. We also carry out a thorough asbestos survey in Birmingham for properties across the Midlands.
Wherever your property is located, our qualified surveyors can assess the risk from asbestos window putty glazing and provide the documentation you need to comply with your legal duties.
Getting Your Property Assessed by Supernova Asbestos Surveys
Supernova Asbestos Surveys holds UKAS accreditation and has completed over 50,000 surveys across the UK. Our surveyors are trained to identify asbestos-containing glazing materials that others might miss, and we provide clear written reports that meet the requirements of HSG264 and the Control of Asbestos Regulations.
Whether you need a management survey for an occupied building, a refurbishment survey ahead of planned works, or standalone asbestos testing of specific materials, we can help. Our team will advise on the most appropriate course of action for your specific situation and support you at every stage — from initial survey through to management planning and, where necessary, safe removal.
Call us on 020 4586 0680 or visit asbestos-surveys.org.uk to arrange a survey or speak to one of our specialists about asbestos window putty glazing in your property.
Frequently Asked Questions
Does all old window putty contain asbestos?
Not all old window putty contains asbestos, but there is no way to tell by looking at it. Asbestos was commonly added to glazing compounds in buildings constructed before the 1980s, and some products continued to be used into the early 1990s. The only way to confirm whether your putty contains asbestos is through laboratory analysis of a sample taken by a qualified surveyor.
Is asbestos window putty dangerous if it looks intact?
Intact, undisturbed asbestos putty presents a lower immediate risk than material that is crumbling or friable. However, it still needs to be identified, recorded in your asbestos register, and monitored regularly. Even putty that appears stable can deteriorate quickly with changes in weather or if disturbed during routine maintenance. Managing it in place is only appropriate when the material is genuinely in good condition and is not at risk of being disturbed.
Can I remove asbestos window putty myself?
No. Removing asbestos-containing putty yourself is dangerous and, depending on the type of asbestos present, may be illegal without the appropriate licence. Disturbing asbestos putty without proper controls releases microscopic fibres that can cause serious and potentially fatal lung diseases. Always engage a licensed asbestos professional to carry out or oversee removal work.
What type of survey do I need for asbestos in window putty?
For an occupied building where you need to understand what asbestos-containing materials are present, a management survey is the appropriate starting point. If you are planning refurbishment or window replacement work, a refurbishment survey is required before any work begins. A demolition survey is needed if the building is to be demolished. A qualified surveyor can advise which survey is right for your situation.
How long does it take to get asbestos putty tested?
The process typically involves a site visit by a qualified surveyor to collect bulk samples safely, followed by laboratory analysis at an accredited facility. Turnaround times vary depending on the laboratory, but results are often available within a few working days of the sample being submitted. Supernova Asbestos Surveys can advise on expected timescales when you book your survey or testing appointment.