For most residential carports, a 4-inch thick concrete slab is sufficient. For carport housing heavier vehicles or areas with poor soil conditions, consider increasing to 5-6 inches. Always check local building codes as some jurisdictions may have specific requirements.

Footings are typically recommended for larger metal buildings, structures in areas with deep frost lines, or buildings placed on poor soil conditions. Footings help distribute the weight of your structure and prevent settling or shifting over time.

Most concrete reaches about 70% of its strength after 7 days of curing. For residential carports and smaller structures, this is often sufficient. For larger commercial metal buildings, waiting the full 28-day cure time is recommended for maximum strength.

Fiber-reinforced concrete contains thousands of small synthetic fibers that help prevent cracking throughout the slab. Rebar (steel reinforcement bars) provides structural strength and helps prevent major cracking. For best results with metal buildings, using both fiber-reinforced concrete and strategic rebar placement is ideal.

Concrete costs vary by region, but generally run between $120-$200 per cubic yard for ready-mix delivered. For a standard 20’×20′ carport slab at 4″ thick, expect to pay approximately $800-$1,300 for the concrete alone, not including labor or site preparation.

While possible, pouring your concrete slab in one continuous pour is strongly recommended for metal buildings. Seams between pours can create weak points and potential water intrusion. If a large building necessitates multiple pours, consult with a structural engineer for proper joint design.

Yes, a vapor barrier (typically 6-mil polyethylene sheeting) is recommended under metal building slabs. This prevents ground moisture from migrating through the concrete, which can cause condensation issues inside your metal building.

There are several different effective ways to pour a concrete slab. You should always speak to your local township to get an idea of what your areas requirements are or consult with a local concrete professional.

We recommend most of our customers to either pour the slab the same size as the building to prevent water intrusion. Another good option is to pour the slab 6-12 inches beyond the dimensions of your structure with a built in slope to help prevent foundation erosion.

Yes, though it requires temporarily removing or supporting the structure. Many customers initially install on ground anchors then later add a concrete foundation.

Your concrete slab should have a slight slope (typically 1/8″ to 1/4″ per foot) away from the center to prevent water pooling. For enclosed metal buildings, the slab should be 4-6″ above the surrounding grade to prevent water intrusion.

Check out our How to Pour the Perfect Concrete Slab Guide.