Footings are the part of a project nobody sees once it is finished, and they are the part that decides whether it stays level. In Michigan, the ground freezes deep every winter. Frozen soil expands and lifts whatever sits on it, then drops it again in the spring thaw. A garage, porch or addition built on footings that stop above the frost line can move with the seasons, which shows up as cracked walls, doors that stick and steps that pull away from the house.
Rock Solid Exteriors is a family-owned, locally owned and operated contractor in Clinton Township, in business since 1997. We install concrete footings and rat walls for garages, sheds, porches, decks and raised patios, and we also pour the slab or flatwork that goes with them. Call (844) 757-6543 or request a free estimate.
Footings, Frost Walls and Rat Walls: Plain-Language Definitions
- Footing
- A concrete base, wider than the wall or post it supports, that spreads the load onto firm soil. It can be continuous under a wall (a strip footing) or individual under a post or column.
- Frost footing / frost wall
- A footing and short foundation wall that reach below the frost line, so frost cannot get under the structure and lift it.
- Rat wall
- A concrete wall around the perimeter of a slab or structure that extends down into the ground. It blocks animals such as rats, mice, raccoons and skunks from digging under the slab, and helps keep the soil under the edge of the slab in place.
How Deep Do Footings Go in Michigan?
The Michigan Residential Code generally requires exterior footings to extend at least 42 inches below grade, which is the frost depth used across Southeast Michigan. There are exceptions. Some small detached accessory buildings of light-frame construction do not need frost-depth footings, and some designs use other approved methods. Your local building department decides what your project needs when it reviews the permit. Rules are applied by each city and township, so the answer in Sterling Heights may not be the same as in Lapeer.
Which Projects Need Footings?
- Attached garages and home additions. These connect to the house, so they need frost-depth foundations to keep them moving together with the house, not apart from it.
- Detached garages. Depending on size and local code, a detached garage may use frost footings, or a slab with a thickened edge or a rat wall. See garage pads.
- Porches. A porch tied to the house needs footings that will not heave, or the porch will pull away from the door.
- Decks and raised patios. Posts and walls that carry a raised surface need footings sized for the load.
- Sheds and other outbuildings, depending on size and the building department’s requirements.
Not sure if yours does? We will look at the plans and the site with you and explain what the building department is likely to ask for.
Where Rat Walls Make Sense
Rat walls are common around sheds, detached garages, decks and patios, especially where the yard backs up to fields, woods, a creek or a drain. Animals like the dry, sheltered space under a slab or a low deck. Once they dig in, they undermine the soil the slab sits on and are hard to evict. A continuous concrete wall around the perimeter, extending below grade, closes that space off for good. It costs far less to build one during construction than to deal with animals, and the damage they cause, afterwards.
How We Build Footings and Rat Walls
- Review the plans. We go over the drawings or the project with you: footing size, depth, locations and anything the building department has asked for.
- Permits and utilities. Our crews pull city permits where required. Utilities are marked through MISS DIG before any digging, which is especially important at 42 inches deep.
- Layout and excavation. The footprint is laid out and the trenches or holes are dug to the required depth, down to firm, undisturbed soil.
- Forms and reinforcement. Forms are set where needed, and reinforcement is placed as the plans call for.
- Inspection. Footing excavations are commonly inspected before concrete is placed. We schedule around it so the pour happens only after approval.
- Pour. Concrete is placed, and anchor bolts or dowels are set where the next stage of construction needs them.
- Backfill and next steps. Once the concrete has set, the area is backfilled, ready for the slab, walls or framing.
What Affects the Price
Footing prices depend heavily on the plans, so we do not publish a per-foot number. The main factors are:
- Total length of footing or rat wall, and the number of individual post footings
- Depth. Frost-depth footings take far more digging and concrete than shallow ones.
- Size and reinforcement called for on the plans
- Soil and site: clay, fill, water in the trench, slope and access for equipment
- Whether the slab or flatwork is poured by the same crew, which saves a separate mobilization
0% financing for 60 months is available on approved credit, and veterans receive a 10% discount. See financing.
Footings and Rat Walls FAQ
What is a rat wall?
A concrete wall around the edge of a slab or structure that extends below the ground to keep animals from burrowing underneath.
Does a slab on grade have footings?
Some do and some do not. Many garage and shed slabs use a thickened edge poured with the slab, some add a rat wall, and structures that need frost protection get frost footings. The building, its size and your local code decide.
Why 42 inches?
That is the frost depth the Michigan Residential Code uses for footings in this part of the state. Footings below it sit in soil that does not freeze, so frost heave cannot lift them.
Can you pour footings in winter?
Frozen ground and freezing temperatures complicate excavation and curing. Concrete must not be placed on frozen soil. Timing is discussed with each project.
Do you build the garage or deck too?
We handle the concrete: footings, rat walls, slabs and flatwork. We coordinate timing and layout with whoever is framing the structure.
Footings and Rat Walls Across Southeast Michigan
We install footings and rat walls throughout Clinton Township, Sterling Heights, Macomb Township, Shelby Township, Warren, St. Clair Shores, Chesterfield, Roseville, Mount Clemens, Troy, Rochester Hills and Lapeer, for homeowners and builders. For the rest of our concrete work, see concrete services. Builders and developers may also want to see subdivision road installation.
Get a Free Footing Estimate
Have plans? Have them handy when you call (844) 757-6543 or request your free estimate. Office hours: Monday to Friday 9 AM to 8 PM, Saturday 9 AM to 3 PM, closed Sunday. Michigan Residential Builder License 2102205396.
Rock Solid Exteriors, 42452 Hayes Rd #2a, Clinton Township, MI 48038.