I did a key word search through the 2006 ibc using several different key words garage floor floor slope slope to drain 1 8 per foot 1 8 in 12 and came up dry.
Irc garage floor slope.
Of course we don t have to deal with heavy snow etc.
Btw how about filling out your profile so we have an idea what area you live in.
1 4 a foot is a lot.
The building code requires that a garage floor be sloped towards the door but does not specify a minimum slope.
Frankcastelvecchi on argument for keeping it flush is accessibility particularly with the aging population.
Aci 117 90 st andard specifications for tolerances for concrete construction and materials gives a level alignment tolerance of 3 4 inch for top of slab elevation of slabs on grade.
Here a more typical slope would be 2 5 or 3.
If roof trusses or rafters bear on header special header design may be required double 2x4 or 2x6 trimmers each end of overhead door header garage door opening header size x.
Here is the citation from the international residential code irc.
The 06 merely states that the floor must be non cumbustible material and if for the storage of automobiles be sloped to facilitate drainage.
Floor slope back to front not less than 1 8 per ft irc 309 1 3 1 2 minimum concrete slab all vegetation shall be removed 408 5 dimension note.
It only requires the garage floor to slope for drainage.
From the irc r309 4.
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.
On a 20 deep garage concrete sloping toward the big door that would be 5 and 6 on a 24 deep garage.
The area of floor used for parking of automobiles or other vehicles shall be sloped to facilitate the movement of liquids to a drain or toward the main.
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.
A 2 slope will probably ensure better drainage we could also find no slope tolerance for use when a floor slope is specified.
The irc does not specify the degree of slope in 309 4.
The sills of all door openings between the garage and dwelling shall be raised not less than four inches above the garage floor 1999 section 407 5 the sills of all door openings between private garages and adjacent interior spaces shall be raised not less than 4 inches above the garage floor.