New patio level and DPC Question (images attached)

Hello

I'm hoping to get any advice on new patio level and the DPC

As shown in pictures the existing concrete patio sits 17cm below the DPC.



I'm hoping to lay sandstone and a border of block paving on top of the existing concrete as shown below , patio has a slope running away from the wall towards another drain channel. both drain channels will be connected via a pipe running under the paving, therefore any water gets collected in the drain shown below will make it's way to the soakaway.





Drain channel in picture is 9cm tall so it will sit just on the level of the bottom of the vent brick, leaving 7.5-8cm gap towards the DPC.

below suggestion is taken from https://www.pavingexpert.com/dpc01




Just to put my mind at ease with this setup

1. Do you see any issues in my above setup? suggestions welcome.

2. Do I need an air vent cover which has openings pointing downward to stop any rain water spalshing getting through?


If the above setup is ok then,

3. Should I leave gaps on sides of the drainage channel as highlighted in the picture above?

4. Should I fix the drainage channel with mortar or fill it up with sand or gravel to fill up the voids?


Many thanks for reading, any help is much appriciated.

You can use shallow drainage channel 60mm ish,will help increase height to dpc and airbrick, and bed in sharp sand and cement,also bed block trim in same mix. I have 100mm to dpc on my patio's with similar setup to yours and no problems,you could put a bead of silicon along back of channel against wall,no need on front.
https://www.tradepipes.co.uk/low-pr...fsJ3W26qyyidNU37yGaLCZqDUkDsYAIhoCflwQAvD_BwE

Thanks very much for your response Charlie.