Our house has a raised patio - a tall one at 900mm - built onto the back
of the house. You can more or less see it he

http://li.zoocdn.com/26c88c6143f7f50..._645_430.j pg

There is a limited damp problem inside the house as you'd expect from
bridging the damp course like this.

I'd like to functionally retain and extend the patio, so I am thinking
about replacing most of it and building a new block wall with an air gap
between the patio and the house. Am I going to run into problems if I
bridge the gap at the top of the wall with paving?