Types of Asphalts for Driveways in Michigan

State of Michigan Driveway Permit Laws

• The state of Michigan does not mandate any particular class of materials to be used in driveway construction, but the legislature does require that a permit be obtained before a driveway can be built. Sections 4 and 5 of the Driveway, Banners Parades Act 200 of 1969 require that a local government agency grant permits for driveways in conformity with rules "consistent with the public safety." State law also requires reasonable standards "for the design and the location of driveways" and may require that "driveways shall be hard-surfaced."

Local Requirements

• Permit requirements are set by either the county road commission or a local city fulfilling the same role. Basic requirements are common to most Michigan counties. Hard-surface driveways and asphalt driveways must both meet local land use rules and zoning requirements.

Basic Types of Driveway Asphalt

• Driveway asphalt is roughly comparable to asphalt used on roads and highways, a mixture of rock and a kind of petroleum product. Blacktop used for a residential driveway is much thinner than that used on highways, however. There are two acceptable asphalt products for Michigan driveways---a hot mixture and a cold mixture. The hot mixture is made by a specialized machine compressing a hot mixture of aggregate (rock) and a petroleum binder until it is the proper depth and mass required. The cold mixture uses a combination of aggregate and the binder material. Cold mixture is not used as often, since it develops soft spots when exposed to extreme heat.

Local Building Code Requirements

• Local building codes mandate the base that is required under a Michigan driveway. A thick and solid base is needed upon which to apply the asphalt for it to last. Many local building codes permit a typical contractor's recommendation of a compressed base of rock with a depth of at least eight inches. The asphalt must be compacted during installation, or the blacktop may develop soft spots when the weather gets hot. Local building codes also have drainage requirements, typically a driveway slope of at least 1/4 inch per foot.

Local Zoning Boards

• Local Michigan zoning boards also have requirements that must be met in order for an asphalt driveway to be built. Each zoning board has rules for how large a driveway may be, and the required depth of the asphalt. Some localities have rules for building a driveway over a right-of-way, whether city or third-party owned. Check with your municipality before setting out on this project.