Engineered Plans and Pad Instructions for Carports/Metal Buildings

If your locality requires a permit for a carport or metal building, they may also request an engineered plan.  You will find the plans for the most common size carports and metal buildings that we offer below. These are generic plans based on the width of your building. The length or height does not matter.  If you have any other questions please let us know.

Plan details

Concrete Pad Instructions

The building foundation is one of the most vital aspects of your metal building. Making sure that the concrete foundation is poured correctly will help ensure that you are happy with your building and help resist water seepage into your building under the bottom rail.

Concrete can be poured to the exact dimension of the building but it is not recommended because, “when applying concrete anchors the foundation can be chipped or cracked at the edges for which All Steel
Carports cannot be responsible.” The following method is recommended:


  1. The concrete should be poured 3 inches longer AND wider than the footprint of the building.

For Example, an 18ft wide x 21 ft Long (Roof dimension) building would have a footprint of 18ft wide x 20ft long (frame is 1ft shorter than roof!)  Your pad dimensions would then need to be 18′ 3″ wide X 20′ 3″ long.  The outside 1.5 inches of concrete all around the pad should be sloped down 1/4 inch so that so that any water that falls on it will run off the pad.  Make sure that this same procedure is followed for door locations.  Note:  All Steel Carports does not offer any warranty coverage for water seeping under the buildings base rail or doors.  

The installation contractor will then center the building on the pad so that the sloped outside 1.5″ of concrete is exposed all around the building.

Note:  There is also a Silicone Option that can be added where silicone will be beaded under the base rail by the installation contractor.  This will also help prevent water from entering the building under the rail, but it is not guaranteed or covered by any warranty, and due to temperature changes the seal may be broken and the silicone may need to be reapplied by the customer.

Gravel Pad Instructions:

If the building is going to be installed on gravel or crushed limestone, the pad needs to be completely level (this is the responsibility of the customer), and it is recommended that the gravel or crushed limestone extend 12 inches beyond the outside of the buildings frame.

Future Concrete:

If concrete is desired after the building is erected, simply scrape out 1.5″ of gravel and then pour the concrete to the top of the 2.5″ frame.