Asbestos was added to a wide range of building products for decades, and some older mastics, sealants and putties were among them. The risk is highest in buildings put up or refurbished before 2000. Resealing a window or a movement joint means cutting out and scraping the old material, which can release fibres if asbestos is present. This guide explains what duty holders and contractors should check before that work begins.
Why old sealant is a concern
Sealants and mastics from that era may look just like modern products. Some are hard and brittle, some still slightly soft. You can’t tell from appearance whether a product contains asbestos. Only sampling and laboratory analysis can confirm it. Typical locations to treat with care include old window and door perimeters, panel joints on older blocks, joints in plant rooms and seals around older pipework and ducts.
The duty to manage
In non-domestic premises, the duty to manage asbestos sits with the dutyholder under the Control of Asbestos Regulations 2012. That is usually the owner, the employer or whoever has responsibility for maintenance and repair under a lease or contract. In practice, the dutyholder should have an asbestos register and a management plan, based on a survey. The HSE’s asbestos guidance pages set out what the duty involves.
What to check before work starts
- Look up the joints to be worked on in the asbestos register or survey.
- Check whether the survey actually covered those materials. A management survey may not have sampled every joint, and work that disturbs the fabric may need a refurbishment survey.
- Share the relevant findings with the contractor before they price and before they start.
- If the information is missing or unclear, arrange sampling before any cutting or scraping.
Under CDM 2015, clients must also pass relevant information to those carrying out the work. See our guide to CDM and RAMS for sealant work.
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If asbestos is suspected on site
Sometimes a material that was not on the register turns up during the job. In that case work on that material should stop until it has been tested. We don’t remove asbestos-containing materials. If testing confirms asbestos, its removal or management is a matter for the dutyholder and a suitable asbestos contractor. Sealing can carry on in unaffected areas, or resume once the material has been dealt with.
Planning around the results
If the results come back clear, the job goes ahead as planned. Where some joints are affected, the programme may need to change. It helps to build sampling time into the plan for older buildings, especially on large estates or multi-block resealing programmes. Managing agents and housing associations planning block-wide work will find more in our sealant planning guide.
Information the contractor will need
When you ask for a quote on an older building, include the relevant extract from the asbestos register or survey, or say clearly that the joints have not been sampled. Note the age of the building and any past refurbishments you know about. That lets the contractor plan the job properly and avoids a stop partway through. Tell us what site paperwork you need (RAMS, insurance certificate, CSCS details) and we’ll confirm with the quote. HSE’s guidance on CDM 2015 is on the HSE website.
Quick answers
Do all old mastics contain asbestos?
No. Many older sealants contain no asbestos at all. The point is that you can’t tell by looking, so in older non-domestic buildings the register should be checked and suspect materials tested before they are disturbed.
Who pays for asbestos testing?
That is a matter for the dutyholder and the contract. Testing is normally arranged by the building owner or their agent, separately from the sealant work.
Can you test the sealant for us?
No. Sampling and analysis should be carried out by a competent asbestos surveyor and laboratory. Once the results are in, we can plan the sealant work around them.
Does this apply to buildings built after 2000?
The risk is far lower, but the dutyholder should still check the asbestos information available for the building before disturbing materials.
Related services
- Mastic sealing for building owners and managing agents
- Facade and window perimeter sealing
- Commercial sealant contractors
More advice
- CDM and RAMS Basics for Sealant Work
- Sealant Planning for Managing Agents
- Leaks Around Windows on Commercial Buildings
- How to Choose a Commercial Sealant Contractor
- All advice
This guide is general information about sealant work. It isn’t legal, fire-safety or structural advice; for those, speak to a qualified professional.