Laying brick pavers on tarmac or concrete?

[SandMan]

Just wondered what people's thoughts are on this subject, if the tarmac or concrete doesn't have any cracks or holes in and is virtually water tight after many years of being used would you recommend lay brick pavers on it?

In my past experience I have experienced that even after the pavers dry out after laying them in the rain or rains before you can get your kiln dry sand in place, the sand you lay them on (Seen before on a sloping driveway) comes up further down the driveway through the pavers whilst being wacked even though you have kiln dried it, as anyone else experienced this and though twice about laying them on such solid foundation that is water tight?

[thedoctor]

Never experienced any problems laying pavers on a solid base as long as they are laid to a slope themselves for the water to run off.