Indian stone on tarmac - Indian stone laid on tarmac

[rstoke]

hi im new to this and would like some information regarding indian stone. a relative had his drive and patio done in indian stone about 5 years ago, and has now started to lift in certain areas, when the contractor who did the job came to look at it he said it was beacuse salt had been put down. im in the building trade (roofer) and no that this isnt the reason the slabs were lifting, having lifted one of the slabs and having a dig down there is about 70 ml of hardcore and the slabs are spotted, having refused to do anything about it i proceeded to repair it myself, when i dug it up and further down i found that he'd gone straight over tarmac, in the high spots there is about 70 ml of hardcore then a cement spot. his quote stated that there would be a minimum of 150 ml hardcore, and at the low points where it meets the drain there is non at all, could you please inform me of the problems of laying on tarmac, is it a problem?? no hardcore etc, im no flagger but im sure that the tarmac layer is trapping water between the two layers causing it to lift with the frost. is this true or is his salt theory actually fact?? thanks

[seanandruby]

He laid 70ml hardcore then spot bedding then slabs, on top of an existing tarmac plus sub base? Surely he has compromised the dpc?
Should of taken the tarmac up and re-used the existing sub base. No way should he of 5 bedded. It is very likely down to freeze thaw action. The word cowboy springs to mind. I'd sack him now and get another contractor to give you a price.

[rstoke]

too late to be sacked hes already done the job, this was 5 years ago. there was previously tarmac down which was thought to be removed when the stone was laid, but it wasnt. he lust spotted the indian stone and put hardcore down in the deeper areas to bring the levels up, i presume to use less mortar.he blamed the llifting of the slabs on salt that had been thrown on in the winter. i just wanted to find out the facts so that when he returns to give his version of it lifting i can throw the facts at him.

[seanandruby]

I meant sack as in don't let him put it right. his salt theory is wrong mate. It is because he left voids underneath to trap water which, with the harsh winter we've had would of froze, thereby lifting the flags and making them move....freeze and thaw. You have a solid tarmac base then, "in parts" you have bits of m o t. You will get differential settlement, also adding to the failure of the bedding etc: How high is the finished level, does it compromise the d p c? Photo's would be good.

[Dave_L]

The job was doomed to fail from day one - I'm suprised it has lasted this long!

[local patios and driveway]

small claims...

[Suggers]

small claims - 5 yrs - don't be silly - long gone - I'm amazed injun has lasted this long ? - we demand photos....

[rstoke]

I will post some pics soon as poss. Can I lay the stone on full bed of mortar straight onto the Tarmac. If I drill holes in it. ?? It's going to require 6 inches of mortar in places though. Is this possible. 15 grand has already been spent and trying to save as much as poss but get it looking something like that will last. Thanks

[lutonlagerlout]

150mm of mortar is way too much
30-60 mm is the range maybe 70 on odd bits but 150 will cost you a fortune
can you not drill holes then top up the levels with type 1?
LLL

[rstoke]

i dont know can i?? lol,, its already got some hardcore down, shall i re-use that or this type 1??