I am doing the design of a deck footing and in many places where I read it says that the footing (sonotube) should be set with the top end terminated 2" above the ground level
In my case I am building on top of a patio and I need to understand why 2" and if those 2" must be above soil level (which is way below the three layers -gravel, crushed stone and bricks-that build my patio) or just above the patio level
Please have a look at the diagram below and tell me which case is recommended and why
Update:The recommendation regarding the 2" comes from this book step 5 on that page