In This Guide
Overview of asbestos insulation
Asbestos was used extensively as an insulation material in UK buildings from the 1930s through to the mid-1980s. Its thermal resistance, fire-retardant properties, and low cost made it the insulation material of choice for a wide range of applications — from pipe lagging in Victorian terraces to spray coatings in post-war commercial buildings.
The complete ban on the use of all asbestos types in the UK came into force in 1999. However, because asbestos-containing insulation materials were used for over 50 years and were often installed in concealed locations, they remain present in a very large number of UK buildings — particularly those built or refurbished before 1985.
Understanding the different types of asbestos insulation, their locations, and their relative risk levels is essential for anyone responsible for managing a building, planning renovation work, or dealing with a suspected asbestos find.
Key principle: Asbestos insulation is most dangerous when it is in a friable (easily crumbled) condition or when it is disturbed. Intact, well-bound asbestos insulation that is not being disturbed presents a much lower risk than damaged or degraded material.
Asbestos insulation board (AIB)
Asbestos insulation board — commonly abbreviated to AIB — is one of the most hazardous and widely encountered forms of asbestos insulation in UK buildings. It was manufactured as flat or profiled boards and used extensively in the 1950s, 1960s, and 1970s for fire protection, thermal insulation, and acoustic insulation.
Common locations
- Fire doors and door linings
- Ceiling tiles and suspended ceilings
- Partition walls and wall panels
- Heating cupboard linings
- Behind electrical panels and fuse boxes
- Soffit boards under stairs
- Lift shafts and service ducts
- Structural fire protection around steelwork
Key characteristics
- Typically grey, off-white, or buff coloured
- Flat, rigid boards — often 6mm, 9mm, or 12mm thick
- May have a textured or smooth surface
- Often painted or covered with other materials
- Asbestos content typically 15–40% by weight
- Usually contains amosite (brown) or chrysotile (white)
- Licensed removal required in most cases
- High risk when cut, drilled, or broken
AIB is classified as a high-risk asbestos-containing material because it is relatively friable compared to asbestos cement and releases fibres readily when disturbed. The removal of AIB is classified as licensed work under CAR 2012 in most circumstances and must be carried out by a contractor holding a current HSE asbestos licence. See our Asbestos Insulation Removal service for more information.
Pipe and boiler lagging
Asbestos pipe lagging was used extensively to insulate hot water pipes, steam pipes, and boilers in both domestic and commercial buildings. It was applied as a paste or pre-formed sections and was particularly common in buildings constructed or refurbished between the 1930s and 1970s.
Pipe lagging is one of the most hazardous forms of asbestos insulation because it is typically friable — it can be crumbled by hand — and often contains high concentrations of amphibole asbestos (amosite or crocidolite), which are the most dangerous fibre types. Degraded or damaged pipe lagging can shed fibres continuously into the surrounding air.
High priority for removal: Damaged or degraded asbestos pipe lagging is considered a high-priority material for removal or encapsulation. If you find damaged lagging in your property, do not touch it — contact a licensed asbestos contractor immediately.
Common locations for asbestos pipe lagging include: boiler rooms and plant rooms, roof spaces and loft areas, under-floor voids, service ducts and risers, and around hot water cylinders. In domestic properties, asbestos lagging is most commonly found in properties built before 1970 and is particularly prevalent in Victorian and Edwardian terraces that have been updated with central heating systems during the mid-20th century.
Spray coatings and limpet asbestos
Asbestos spray coatings — sometimes known as "limpet asbestos" — were applied by spraying a slurry of asbestos fibres and binder onto structural steelwork, concrete, and other surfaces for fire protection and thermal and acoustic insulation. They were widely used in commercial, industrial, and public buildings from the 1940s through to the early 1970s.
Spray coatings typically contain very high concentrations of asbestos — often 55–85% by weight — and are highly friable. They are considered the most hazardous form of asbestos insulation and their removal is always classified as licensed work. Spray coatings are most commonly found in: structural steelwork in commercial and industrial buildings, underside of concrete decks and floors, boiler rooms and plant rooms, and in some cases beneath suspended ceilings.
The use of asbestos spray coatings was prohibited in the UK in 1986. However, because they were often applied in concealed locations and then covered by subsequent building works, they can be discovered unexpectedly during refurbishment or demolition. See our Asbestos Spray Coating Removal service.
Loose-fill asbestos insulation
Loose-fill asbestos insulation was used in a relatively small number of UK properties — primarily local authority housing — during the 1960s and early 1970s as cavity wall and loft insulation. It was typically composed of pure amosite or crocidolite fibres with no binding agent, making it extremely friable and hazardous.
The presence of loose-fill asbestos insulation in a property is considered a serious hazard. Because the fibres are unbound, any disturbance — including normal household activities such as accessing the loft — can release large quantities of fibres. Properties with confirmed loose-fill asbestos insulation are subject to specific HSE guidance and may require specialist remediation.
Loose-fill asbestos insulation can be identified by its appearance: it looks similar to grey or off-white fluffy material, sometimes described as resembling grey candy floss or fibreglass insulation. If you suspect your loft or cavity walls contain loose-fill asbestos insulation, do not enter the loft space — contact a licensed asbestos contractor immediately.
Thermal insulation products
Beyond the major categories above, asbestos was incorporated into a wide range of thermal insulation products used in domestic and commercial settings. These include:
Identifying asbestos insulation
Asbestos insulation cannot be reliably identified by visual inspection alone. Laboratory analysis of a sample is required for a definitive result. However, the following visual indicators can help identify materials that warrant further investigation:
| Material | Visual Appearance | Typical Location | Risk Level |
|---|---|---|---|
| AIB | Grey/buff flat boards, often painted | Ceilings, fire doors, wall panels | High |
| Pipe lagging | White/grey fibrous wrap around pipes | Boiler rooms, roof spaces, under floors | Very High |
| Spray coating | Rough, grey/brown textured surface | Structural steelwork, concrete soffits | Very High |
| Loose fill | Grey/white fluffy fibrous material | Loft spaces, cavity walls | Extreme |
| Millboard | Dense dark grey/brown rigid board | Behind fireplaces, boiler surrounds | High |
| Rope/gaskets | White/grey rope or flat strips | Boiler joints, furnace doors | High |
| Paper/felt | Thin grey/brown sheet material | Under floor tiles, behind panels | Medium |
Risk levels by insulation type
The risk posed by asbestos insulation depends on three factors: the friability of the material (how easily it releases fibres), the type of asbestos present (amphibole fibres are more hazardous than chrysotile), and the condition of the material (damaged material releases more fibres than intact material).
As a general principle, asbestos insulation materials are significantly more hazardous than asbestos cement products (such as corrugated roofing sheets) because they are more friable and typically contain higher concentrations of amphibole asbestos. This is why the removal of most asbestos insulation is classified as licensed work under CAR 2012, whereas the removal of asbestos cement is often classified as non-licensed or notifiable non-licensed work.
Removal and management
The removal of asbestos insulation is almost always classified as licensed work under CAR 2012, meaning it must be carried out by a contractor holding a current HSE asbestos licence. The only exceptions are certain types of asbestos insulation work that fall within the notifiable non-licensed work (NNLW) category — but these are relatively narrow exceptions and professional advice should always be sought.
Where asbestos insulation is in good condition and is not being disturbed, it may be appropriate to leave it in place and manage it through an asbestos register and management plan. This is a legitimate and often recommended approach for AIB in commercial buildings. However, for domestic properties — particularly where children are present — removal is generally the preferred option.
Pro Asbestos Removal carries out licensed asbestos insulation removal across Surrey, London, and the South East. We provide a full service from initial survey and sampling through to removal, air testing, and disposal with full documentation. See our Asbestos Insulation Removal service page for more information or request a free no-obligation quotation.