The building code requires that a garage floor be sloped towards the door but does not specify a minimum slope.
Irc code garage floor slope.
7 inches sounds like too much both visually and from a walkability standpoint so the most i m going to consider is 3 5.
The international residential code irc lays out a series of requirements for pouring a concrete slab on grade.
Appliances located in a garage or carport shall be protected from impact by automobiles.
The slab has to be at least 3 5 thick and possibly thicker for expansive or other difficult soils.
The garage is 28 ft deep so 1 8 to 1 4 inches per foot means the slab shoub be 3 5 to 7 inches higher at the end opposite the door.
Asphalt surfaces shall be permitted at ground level in carports.
Connection of a parking garage with any room in which there is a fuel fired appliance shall be by means of a vestibule providing a two doorway separation.
If bollards or stanchions are not installed then the unit must be raised 6 feet above the garage floor per irc g2408 3 305 5.
Getting ready to pour a garage floor slab.
Here is the citation from the international residential code irc.
2018 international residential code chapter 3 building planning 2 instructor gil rossmiller in the construction industry for over 40 years icc irc plumbing mechanical code development committee icc commercial energy code development committee.
Its more than just forms and pouring concrete.
The area of floor used for parking automobiles shall be sloped to facilitate the movement of liquids to a drain or toward the main vehicle entry doorway.
It is usually 1 8 to 1 4 per foot.
Appliances located in private garages shall be installed with a minimum clearance of 6 feet above the floor.
A single door shall be allowed provided the sources of ignition in the appliance are at least 18 inches 457 mm above the floor.