Removing Concrete Slab Roof With Suspected Asbestos Sheet Under


21 Mar 2021
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United Kingdom

I need to remove a concrete slab roof 1.2mX3mX120mm from our outbuilding attached to our garage. My original plan was to nibble away at it with a 9" grinder and a small breaker to take it off in small sections, and risk assess as i go. However on further inspection the under side looks like sheet material which i presume is how they cast.framed the concrete originally and with it being a 1950's house i have a strong feeling this is possible asbestos.

Removing Asbestos I know you have to be PPE'd up and have polythene sheets and tape to seal up the sheets unbroken. However I don't know how i can remove the concrete slab without it breaking the asbestos sheet underneath as it will either be bonded together or the vibration will disturb it?

Has anyone any experience with taking down a concrete slab roof with asbestos sheet under? I have ploughed through the web looking for answers. Hoping someone may be able to offer some experience of how to correctly tackle this?

I've added photos of the slab its only under the felted section at the back of the garage.

Many thanks
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Have a piece of the material tested at a local asbestos tester. If it is asbestos it will almost certainly be asbestos cement board (ACM - Asbestos Containing Material) which can be removed by a normal contractor (or DIY) subject to various precautions. Basically, standard ACM grade PPE that you can get from Screwfix; mask, disposable overalls, gloves etc. Wet the material down with a hose spray as its removed. For method you should avoid grinding. Maybe break it up with a breaker. Most importantly is disposal; you should double bag the material and dispose of it at an ACM facility. Most local authorities have them for small domestic quantities.
Hi John,
Thanks for your reply and advice, when removing i assume the concrete slab above would be bonded to the asbestos board below? Will waste removal service accept large lumps of concrete? Assuming there is reinforcement in the concrete element i guess a grinder could be used above the sheet area to get through this, but limit the amount?
Many thanks
My guess is it will come away easily. Grinding through the concrete will be fine. Defo test - it might not be ACM.
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Thank you again for your reply/time Jeds its much appreciated. I have ordered a test kit with good reviews and hope to get a test result sorted by the end of the week which will atleast confirm either way so i can act appropriately. What makes you guess that it won't have keyed to the board? I hope that is the case if it were asbestos as it might make it easier to reduce breakage?

Best regards
From experience. Concrete doesn't normally stick well to asbestos cement sheet. It might have been primed but there would be no reason to do that so it's doubtful. Good luck.
The asbestos test came back as chrysotile. Looks like i'm going to have to do the opposite of rolling my sleeves up.
Chrysotile is the least hazardous asbestos. What you have there is asbestos cement board, which is lower level again. It contains just a few percent of fibre which is bound in a heavy cement matrix, so it just falls harmlessly to the floor. Still need to take precautions though. Wear the PPE and don't do anything to kick up masses of dust; grinding, sawing etc. Wet it down with a hose to help prevent airborne dust forming. Double bag it and tape the bags. Dispose at a waste facility for asbestos. Hopefully it will come away from the concrete easily.

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