Concrete Pad Size Calculator
Thinking about a metal carport or garage for your property? Use this calculator to get an initial understanding of the concrete pad required for your building.
Learn More About Concrete Pads for Metal Carports and Garages
Your concrete pad should be one foot wider and one foot longer than size of carport or metal building you are ordering.
The reason for the larger pad recommendation is because the engineers that designed the metal structures believe a 6″ curtain of concrete on every side is important to ensure proper anchoring and avoid potential concrete cracking at the perimeter.
We would encourage you to check with your local building codes to determine the pad size, pad thickness, footing requirements, and/or any other regulations you must adhere to. Local building codes will always supersede our recommendations.
Alan’s Factory Outlet can deliver and install a metal building after your concrete slab has been poured. We don’t pour concrete slabs, so you will need to hire a local concrete contractor or do it yourself.
Recommended Concrete Pad Sizes
If you don’t want to use the calculator above, you can look up the right size in the list below.
All sizes are listed with width first, then length.
Recommend pad size for specific frame dimensions are as follows:
12′ wide x 20′ long frame, make pad size 13′ wide x 21′ long
12×20, make pad size 13×21
18×20, make pad size 19×21
20×20, make pad size 21×21
22×20, make pad size 23×21
24×20, make pad size 25×21
12×25, make pad size 13×26
18×25, make pad size 19×26
20×25, make pad size 21×26
22×25, make pad size 23×26
24×25, make pad size 25×26
12×30, make pad size 13×31
18×30, make pad size 19×31
20×30, make pad size 21×31
22×30, make pad size 23×31
24×30, make pad size 25×31
12×35, make pad size 13×36
18×35, make pad size 19×36
20×35, make pad size 21×36
22×35, make pad size 23×36
24×35, make pad size 25×36
12×40, make pad size 13×41
18×40, make pad size 19×41
20×40, make pad size 21×41
22×40, make pad size 23×41
24×40, make pad size 25×41
We would encourage you to check with your local building codes to determine the pad size, pad thickness, footing requirements, and/or any other regulations you must adhere to. Local building codes will always supersede our recommendations.
Due to the pad being larger than your building, to provide the “curtain” recommended by engineering, you may experience water leakage under your framing. This can be caused by standing water next to the building. One method we have found to address this issue is to seal the framing to the pad using a concrete sealant. Concrete sealant can be purchased at most local hardware stores. Another method is to slope the 6″ curtain downward very slightly. It is very important that if you slope the concrete curtain, that your level portion of the slab is large enough for the footprint of the building.
