DIY Patio , need a little advice

[ALONG]

Hi , this is my first post and my first big DIY project. So we are doing a patio , concrete slabs straight onto sand. I want to leave a little gap between house and patio slabs to fill with decorative stone. As we are first timers I think this will cut out a lot in unknowns for us and it will look pretty !!! My question is how much of a gap should we have ? We have the hardcore and sand flush with the house to maybe 150mm height , slabs not down yet. Thanks all

 

[sxturbo]

I'd got for brick width, 4"

Make sure weed control fabric is down

 

[OvertonPlumber]

Concrete slabs on sand? Not a very long term option they will crack