# Forum Home Renovation Paving  laying pavers over old concrete base

## mattwilliams78

I have just acquired a load of pavers and am thinking of paving over an old concrete drive way that is in very poor condition (levels, cracking, pervious bits etc). Do I, 
a) lay 50mm sand over existing concrete and then pave straight onto that 
b) rip up all the concrete and do a proper roadbase 
I would much rather leave the concrete in place but I am concerned about drainage. I could smash the concrete up a bit perhaps if that helps? punch some holes? I was planning on breaking a trench at the down stream end of the paving anyway and setting one of those U channel drainage systems in to take off the surface run off. There is already something similar there that handles the runoff from my roof (surely this isn't legal? it certainly isn't well designed) If I set this at the correct finished level I can use it as a retaining edge to the pavers. Surely water would just flow over the top and into my new trench and the substrate wouldn't matter? 
Any other ideas would be appreciated 
Matt

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## mattwilliams78

anything?? it seems to have got lost like my post question.....

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## BRADFORD

I think the best job would be to rip the old concrete up
If the concrete is stable the sand and pavers might be ok 
Regards Bradford

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## mattwilliams78

I suspected that might be the case. I will post some photos to give people an idea of what the concrete currently looks like.

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## diyclown

Matt, I am in the same boat. I have a cracking driveway that have large areas in reasonable condition and then others with pieces missing. I'd been keen to see what you have got. I'll post some pics of my driveway too. I have thought about pavers but with sand and paver thickness it might raise my driveway 150mm which might be too much.

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## mattwilliams78

I haven't checked my post for a while, sorry. 
Sounds like we are definately in the same boat. I will post some pics at the weekend. I'm preparing myself to have to rip up the concrete  :Frown:

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## blak

I paved an area at the back of my house where there was an old slab underneath. I chose to leave the slab there, rather than rip up and put down roadbase.
Pavers are still in good shape 5 years on.

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## Bleedin Thumb

Pave over the existing slab. you will however have to use a well mixed sand /cement bedding mix because once you hob in the edges you won't have anywhere for the water to go leaving the bedding sand saturated. 
Any forces on the paving when the bedding sand is saturated will force water up between the pavers...the water will carry a small amount of sand ....eventually the paving will become uneven. 
So always pave with a strong.....say 5 x 20kg bags of cement to 1 tonne of sand mix when going on top of a slab.

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## mattwilliams78

Those photos I said I was going to put up.  
The first photo shows the bits of concrete slab that I want to lay the pavers over. You can see that there are a couple of patches of dirt that I would need to fill in. I was thinking I would dig those up, put down 100mm of crusher dust/blue metal and compact it down to the same level as the concrete. Then spread 30mm sand across the top of the compacted crusher and concrete. 
The second photo shows the existing driveway with the pavers coming loose in the middle. I will clear all of this, put down the 100mm crusher and compact it, then 30mm sand on top. 
So do you think that concrete is ok to stay in place and pavers on top?

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## Bleedin Thumb

> So do you think that concrete is ok to stay in place and pavers on top?

  You won't get a better base than the concrete slab - read my previous post.

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## mattwilliams78

Thanks BT - will fill those gaps with crusher dust and lay that strong sand mix over the whole lot.

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