Asbestos floor tiles

The floors I treat as suspect on sight

Thermoplastic tiles carrying chrysotile went down in enormous quantities in this country from the 1950s until the early 1980s, in schools, hospitals, council housing, shops and kitchens. Marley was the name I saw most often, and I still find their tiles under three later floors. Blue and brown asbestos were prohibited in 1985 and chrysotile followed in 1999, so anything laid before the mid 1980s gets my attention regardless of how ordinary it looks.

The classic is 9 by 9 inches, roughly 230 millimetres square, in muted marbled greens, browns, greys and reds, brittle enough to snap rather than bend. That said, I have opened plenty of 9 by 9 floors that came back negative, and I have had 12 by 12 tiles come back positive. Size is a prompt to sample, never a diagnosis, because the asbestos and asbestos-free versions were made on the same lines to look the same.

The glue and the backing cause the trouble

Black or dark brown bitumen adhesive under old tiles frequently contains chrysotile, and it does so independently of the tile. I have had negative tiles sitting in positive glue more than once, which is why a job scoped as a single tile sample is often a job scoped wrong. The adhesive is also the part that gets attacked with a scraper, a grinder or a floor sander, so it is the part that generates fibre.

The material people forget completely is old vinyl sheet with a grey-white paper backing. That backing is often nearly pure asbestos, it tears rather than snaps, and it delaminates when the sheet is ripped up, which leaves fibrous debris across the whole room. If you have 1960s or 1970s vinyl sheet in a kitchen or bathroom, treat the backing as the priority, not the top surface.

What is actually under the modern floor

A laminate floor laid in 2010 tells you nothing. Underneath it I routinely find foam underlay, a levelling compound, sheet vinyl, plywood screwed straight through the original tiles, and the tiles themselves still bedded in bitumen. Every screw hole through that plywood went through a tile. Every one of those layers is a decision the next contractor has to make.

So the scope has to follow the work, not the surface. If you are lifting to slab, everything down to the slab is in scope. If you are floating a new floor over the top and fixing nothing, the question is narrower. Tell whoever assesses the floor exactly what tools are coming through the door, because that is what determines what gets sampled.

A positive result does not mean rip it out

Bonded thermoplastic tiles are among the better behaved asbestos products in a building. Intact, stuck down and covered, they release very little, and non-licensed contractors can usually remove them whole where removal is genuinely needed. In an office, a shop or a rented flat, overlaying a sound tile floor is frequently the sensible answer and I have recommended it many times.

Where I argue against leaving them is when the tiles are already lifting, cracked or curling, when the floor takes fixings, when moisture work or underfloor heating is planned, or when the client cannot realistically manage and record the material over the next twenty years. Condition and future plans decide this, not the test result on its own.

Lifting, sanding and grinding

Sanding, grinding or mechanically stripping suspect flooring is the fastest way I know to turn a manageable material into a contaminated building. Bonded material only matters when someone abrades it. That is exactly what a floor sander, a diamond cup wheel or a scraping machine does, and the dust travels well beyond the room.

Do not snap a tile or scrape up glue to see for yourself. Sampling is a controlled job done by a competent person, and identification is analysis by a laboratory accredited by UKAS to ISO/IEC 17025 for the relevant asbestos work. There is more on the analytical side on the asbestos testing page, and the what asbestos can look like page shows the products, with the obvious caveat that no photograph has ever identified a fibre.

Targeted sample or refurbishment survey

When a sample is enough

If one accessible tile and its adhesive are the only materials in play, the layers below are known, and the result answers one clear decision, targeted sampling is proportionate. I ask for a positive-negative decision to be defined up front, otherwise a result arrives and nobody knows what it changes.

When you need the survey

Once work penetrates the floor, crosses into skirtings, ducts or adjoining fabric, or the build-up is unknown, a refurbishment and demolition survey under HSG264 is the honest answer. It is intrusive by design and it locates, so far as is reasonably practicable, the asbestos in the area being worked on. On non-domestic premises and the common parts of blocks, the regulation 4 duty to manage under the Control of Asbestos Regulations 2012 sits with whoever is responsible for maintenance. Private homeowners do not carry that duty in their own house, but any employer or contractor working there still carries duties over foreseeable exposure, which is why the survey usually arrives via the builder rather than the owner.

If tiles turn up mid-job

Stop. Do not sweep, do not vacuum with a domestic machine, do not carry the debris outside in a bin bag, and keep everyone out of the room including the dog. Sweeping a broken tile floor is how a two-hour problem becomes a five-figure clean.

Leave the material where it lies, shut the door and get competent advice before anyone goes back in. The suspected asbestos page sets out what to do in the first hour.