Classic Series 55 in. x 72 in. Primed Steel Cellar Door

I do not know the actual gauge of the steel, but can say they are thick, heavy and quite strong. Highly recommend these doors.

The whole box weighed a little over 200 lbs., the doors themselves are maybe 15-20 lbs each. Not exact weight, but they’re not hard to open.

I didn't need any, because the door fit tight on the top step.

These don’t have classes that I’m aware of. They have size ratings like size “c” etc. The 55x72 I got was a size c. These are not waterproof at all, if that’s what you mean. They are designed to shed water. It’s keeping my basement stairs dry.

Yes and yes. Ship flat and should fit in SUV. Fairly easy assembly.

Hi Cookie, thank you for your inquiry. Unfortunately we do not sell the sides separately on Homedepot.com at this time. We appreciate your business and look forward to serving you in the future. Thank you for shopping Home Depot.

I think it is recommended to install on cement block, this would insure it not rotting out in the future.

Hi, I'm not sure if Home Depot would install the doors. I had a contractor install mine, as these were a replacement for my old doors that had rusted out, and were leaking. All you can do is ask them.

I measured the outside of the rough opening.

It includes everything (doors, sides, header, footer, handle, hardware, 2 hydraulic cylinders to assist opening/closing the doors, and assembly instructions). It comes unassembled, strapped flat down on an oversized pallet.