I am clearing some old paving slabs which have been overgrown and covered with soil. I keep coming across patches of thin (<1mm) black material, looks like bitumen, with some kind of foil backing. It's possible they were stuck to the paving slabs (60cm square smooth concrete slabs) at some point, but if so they have delaminated. I also keep finding bits of broken horticultural glass in the same area which may or may not be related.

Any ideas what this might have been? My concern is whether it could be an ACM. Obviously testing is the way to be sure. But having some idea what it could be will help in working out where else I might find it. enter image description here

  • What is an ACM?
    – SiHa
    May 16 '20 at 11:12
  • 3
    ACM = Asbestos Containing Material, I guess. Anyway, While asbestos is certainly a possibility, it certainly looks like bog-standard roofing felt with aluminum flashing tape. Common when re-roofing and cleanup is not done throughly.Or Aluminium, depending...
    – Ecnerwal
    May 16 '20 at 11:59
  • I had a roof put on 15 years ago and still find nails and bits of roofing in the soil. May 16 '20 at 14:18

It tested negative for asbestos, though the surveyor (in to check out the house) did recommend testing as it was reinforced with some kind of fibre so potentially asbestos. I've dug up several large sections so I think Ecnerwal was right - old shed roofing.

  • Thanks for coming back to let us know the result. Please be sure to give yourself a check mark so everyone knows this question has an acceptable answer.
    – FreeMan
    Jul 13 '20 at 11:14

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