Most bathroom silicone is modern and nothing to worry about. But some older mastics, sealants, putties and fillers were made with asbestos. Disturbing them can release fibres. This guide explains which buildings are at risk, where suspect materials tend to be, and what to do before anyone starts work. It is general guidance, not a substitute for a survey or for HSE’s own advice.
Why old mastic can contain asbestos
Asbestos was widely used in building products in the UK until it was banned in 1999. HSE says buildings built or refurbished before 2000 may contain it (HSE asbestos FAQs). Mastics and sealants were among the products it was added to. HSE publishes a task sheet for workers on removing asbestos-containing mastic, sealant, beading, filler, putty or fixings, which shows these materials do turn up (HSE task sheet A37).
Not every old mastic contains asbestos. Most don’t. But you can’t tell by looking. The only way to know is for a sample to be tested by a competent person.
Which materials to be wary of
Be cautious with any of these in a building from before 2000, especially if they are original:
- Hard, brittle or tar-like mastic around window and door frames
- Old putty or glazing compounds
- Mastic in external joints on older commercial and public buildings
- Black adhesive under old floor tiles, which HSE notes may contain asbestos
- Sealant or filler around old panels, ducts and pipework
Soft, rubbery silicone around a bath that was fitted in recent years is very unlikely to be a concern.
Homes: what to do
HSE’s advice for homes is clear: don’t try to repair or remove asbestos materials yourself, and tell any builders or contractors about asbestos in your home before they start work. You can get advice from an environmental health officer at your local council (HSE asbestos FAQs).
If you are planning work on old window mastic or external joints and your home was built before 2000, consider having the material tested first. If you rent, tell your landlord or agent.
Need it done properly? Mr Mastic covers the South East, London and Scotland, with a one-year guarantee on every job. Call or email for a quick quote.
Commercial and rented buildings
In non-domestic premises, the duty holder must manage asbestos. That includes finding out whether it is present, assessing its condition and making a plan, and giving that information to anyone who might disturb it (HSE: duty to manage asbestos). Common parts of blocks of flats are also covered.
Before any sealant work in an older building, check the asbestos register and share the relevant parts with the contractor. If the register doesn’t cover the joints being worked on, ask for them to be checked first. Our commercial sealant page explains how we plan work on larger sites.
If you think you have disturbed it
Stop work. Keep people out of the area. Don’t sweep or vacuum dust with a normal vacuum cleaner. Get advice from a competent asbestos professional or your local council. HSE’s guidance at hse.gov.uk/asbestos explains the next steps.
Removing old sealant safely depends on knowing what it is. Our guide to removing old silicone is for ordinary bathroom and kitchen sealant only.
Talking to your contractor
Tell any contractor the age of the building when you ask for a quote, and whether you have an asbestos survey or register. If old mastic looks suspect and hasn’t been tested, it is reasonable to expect a contractor to pause and ask, rather than carry on cutting it out.
Quick answers
Does modern silicone contain asbestos?
No. Asbestos was banned in the UK in 1999. Silicone fitted in recent years won’t contain it.
Can I test old mastic myself?
Sampling can disturb the material. HSE advises not to repair or remove asbestos yourself. Use a competent surveyor or testing company.
Do I need a survey before resealing a bath?
Not usually for modern silicone. It is worth considering for old, hard mastic in buildings from before 2000.
Related services
More advice
- How to Remove Old Silicone Sealant
- Window Mastic: When to Replace It and How
- Sealant in Commercial Washrooms
- 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.