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Driveways & Paving

Can I use old tarmac as the sub base for a drive?

Anonymous user 28/02/2024 - 3.03 PM

I want to block pave my tarmac driveway and widen it at the same time. I am currently digging out the extension section to 7-8" deep. I plan to use 5" of sub base under the new section, allowing 3" for the block paving on top. The old drive has not moved or sagged in 30 years so I plan to strip off the tarmac and use the existing sub base as a base for the new paving. Can I use the old tarmac as a sub base for the new section? I know I will have to break it up small, I am not afraid of the back breaking work, I was thinking about 20-30mm chips would do the job, compacted down. Does this sound ok or am I asking for trouble? I am not trying to save money on the hard core, but want to save the hassle of taking the tarmac away! Thanks

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3 Answers

Rowan Groundworks Ltd

Rating: 5 out of 5

Wellingborough

No reason not to use old tarmac, but what you must do is make sure you put enough fines in with the tarmac to get what we call a tight sub-base. If this is not done, the rain water that soaks through the block joints will wash the sand into the voids and let your blocks sink Peter

Answered25 March 2014

Anonymous user

old tarmac is concidered as contaminated waste so there for you wouldnt be able to use it as a sub-base fore your driveway or patio the products that i would most recommend to you would be a semi-dry mixture of concrete or type on mot stone.

Answered27 January 2015

Patios & Drives Turfcare

Rating: 5 out of 5

Ross On Wye

As Peter says above you mush avoid the gaps in the sub base or the sand leaches away. If you are using the tarmac I would lay at least a 50mm layer of type 1 over this to seal it. I presume you will lay a geotextile membrane between the sub soil and any base as this will help strengthen the whole drive and help prevent the base material mixing with the sub soil.

Answered29 March 2014