Blocks to face old Patio

[AndrewW]

I've got an old crazy paving patio, which while still structurally good, look its age, so I?m planning on facing it with blocks. My plan is (after pressure washing) to cement the outside rows in with a mix of 3 sand to 1 cement to form a strong outside frame. For the middle I?m planning on putting 2cm of sand or sand / cement mix to lay the blocks on top of. The current patio is at a slight angle to keep water away from the house which is good and I intend to keep that angle. I?m worried that any water will eventually liquefy the sand. so I thought about either putting a number of holes in the 2cm layer of cement on the lower level to let the water out, but then the sand will also leave, making the blocks uneven over time. The other options I thought of were

1. Break the cement in-between the crazy paving to allow water to leak though, although I suspect there will be some movement, but not as much as before.
2. Use a dry bonded mix of 10 sand to 1 cement mix to hold the main area of the blocks in place. The water will simply run off and water my lawn.

Either way given the thickness I was wondering if tamping the sand down with a vibrating plate was required with such a little depth.

Any views or other options?

[harry]

You must use "sharp" (coarse) sand. If you use fine sand, it comes up the cracks when wet and walked/driven on & you get low spots/puddles. Laying these blocks is not as easy as it looks. If you don't compact the sand you get low points/puddles after a while. The main snag is the weeds you get with so many cracks. And they look shit with algae if you don't pressure wash regularly. Especially light colours.