Everybody knows that a house is only as good as the foundation it sits on. We have found that it is NOT common knowledge that decks, sunrooms, and covered porches (with rare exceptions) cannot sit on existing concrete.
Why not you ask? Great question! The first answer is that the pressure and weight of a structure like the one pictured above would compromise a typical driveway or patio slab (usually 4-6″ thick).
The second reason is, a foundation must sit below the frost line (minimum 32″ in Ohio). If a structure is set upon a driveway or patio slab as the ground freezes and thaws that concrete moves. This is especially dangerous if the other end of a deck or a roof is attached to your house. The part of the structure bearing on the slab will move, the part anchored to your home will resist movement creating a host of issues.
More fun tomorrow, stay tuned!