Cutting patio edge to create french drain - Advice needed

[squid]

Hello all.

We have got a patio which is too high against the back wall. It is only an inch or so below the damp proof course. A surveyor has recommended cutting a 6 inch channel to create a French drain but I'd like to know if I can use an angle grinder to cut the slabs in situ or if I need to lift them out first. The slabs are concrete "crazy paving" type.

Many thanks in advance for your help.

John.

[dig dug dan]

what you will need to do this is a petrol cut off saw, with a water attachment, and a diamond blade.
Best way to get a straight line is to follow a straight piece of timber with your saw, or mark a pencil line, score it with the petrol saw, with the water off(or it washes away the line!), then cut with water on until you are through the slabs, and any cement underneath.
Once you have done this, this line should break out neatly to leave a straight edge.
All you then need to do is check that there is sufficient means of drainage (i.e remove any solid concrete below), and fill with 10mm gravel

This is what I would do, no doubt others may have a few ideas

[alan ditchfield]

If you have a drain close to to patio then it would be safer to do as Dan says but install some channel drains instead of gravel and run the water into the closest drain, this way you will be sure that all the water is kept away from the brickwork and will escape no matter how much rain you get.