What garden patio drainage?

[pachamama]

Hello all

• I have built a new single storey rear extension.
• I wish to landscape the rear garden.
• The soil is heavy clay.
• The garden slopes towards the house

I am proposing a patio 6m wide and 3m from rear of house to garden. Thereafter I wish to add 3 steps UP into the garden.

To create the patio I wanted to use timber decking above the ground level to sit just under the bi-fold threshold (all weather).

What drainage is recommended to disperse surface water in under these conditions?
Please let me know if you need any further info.

Many thanks in advance

 

[r896neo]

Decking is obviously porous so its just an issue of dealing with the water underneath? What is the existing surface the decking is going over?

 

[pachamama]

Heavy clay