Raising an existing patio - Laying a new pation on top of an old one

[Graeme]

We recently go a patio door fitted to the house and I undertook to build the steps to come out of the house onto the patio. Exisiting patio (concrete 600x 600's) is, according to building control about 10 mm to low for this without having a 1m platform from the house first. We want to lay new Indian sandstone flags for this and I'm trying to determine the best way of doing this. As the existing Patio is stable and has been there for many years would it be ok to put the 10:1 mix ontop of the exsiting patio and bed the new stone onto this? - this would need to be 35-50mm thick correct?

At the moment the patio base is 10mm + the 50mm of the exsting slabs - therefore 60mm to low. If I leave the patio in place an add the bedding on top, this should give me the correct base height. Other option would be to lift the slabs, put down a 50mm sharp sand compacted (by me jumping up and down on it) base followed by the bedding. Any advice on which would be better?

Any help/advice would be appreciated. Been looking through the site and it's definately helped but still unsure about this one.....

Cheers

Graeme

[Tony McC]

You should be fine building the new steps on top of the existing patio flags. However, you will need something to form the risers and retain the sand/cement laying course materiual for the step treads.