Lay Decking on top of Existing Decking

[JamieTim]

I have existing decking that is 3 bricks from the dpc. The decking is about 10 years old and structurally ok, the depth to the ground is about 100 - 150mm on loose stone gravel. The very occasional weed does grow through.

I want new decking near level to my patio door.

The decking boards will be run opposite to how they are currently run.

Can I lay new decking on top of existing decking or should I remove the existing decking and build higher?

 

[r896neo]

It would create a horrible moisture trap between the 2 layers of boards and would rot very quickly, you really need to lift it.