do i need two lairs of tarmac

Yes you need 2 layers of tar for driveway, as long as the drive way is prepared correctly 1 base coat layer 50mm 2 wearing layer 20mm

Firstly you would need to dig out the area to 260mm. Lay in a geo textile’terram’ to reinforce the structure. Once this is done, backfill with type 1 at a compacted finish of 150mm. Then lay base course tarmac to a compacted thickness of 70mm. Finally finish off with 30mm of surface course tarmac. Thanks. James (Adur driveways)

It depends on your drive...if it's already tarmac..you just need tack coat and top layer..(sma)

It all depends on if it's a new drive or an existing drive. If it's a new drive and the sub- base is laid correctly then a two coat finish is fine. If you have an existing drive that is tarmac or concrete then you may be able to patch the bad places and overlay the existing drive with 25 to 30mm.