Tarmac as sub-base? - Can tarmac be used as sub-base

[bobatbanktop]

My yard is about 10m square and at present covered in tarmac. The tarmac is stable and capable of taking 7 tonne waggons. I'm thinking of using block paving to renew the yard. Do I really have to take up the tarmac? Level is no problem.

Cheers Bob

[lutonlagerlout]

I have a small holding at about 1000ft above sea level on the Roaches, a mountain in the Peak district.

thats nice for you,why do you want to block pave the yard if there is nothing wrong with it??
i imagine if there is nothing bad with the tarmac it would be ok as a subbase but you need lateral restraint with block paving,plus in an exposed situation like yours if you use concrete blocks they may fade quickly
cheers LLL

[bobatbanktop]

Thanks LLL. The tarmac is old and wont last much longer.

Cheers Bob

[Mark B]

probable best as the tarmac could sink and subside through time causing the block paving to do the same, best to rip it out and topup the type one underneath, i didnt think tarmac could b used a a subbase as it can degrade and compress etc

[geoffdance]

Hi Bob.

If the tarmac is old but sound then you could consider a bitumen based sealant. This will protect the binder in the bitmac from further uv oxidation and deterioration, and by waterproofing it will prevent water ingress and water-damage. You will get a new-look finish that will last about 4-5 years and will withstand heavy trafficking.

If you're starting to pot hole then it's too late.

Geoff