Height
There are two aspects to your metal building's height: overall height, measured on the outside, and interior clearance. The overall height may be regulated by zoning laws, but the clearance height will usually have more of an impact on your design decisions.

At the low end, 10' clearance is plenty for many applications. Heights of up to 30' can accommodate extensive warehouse shelving systems, heavy construction vehicles and tractor-trailers, or even airplanes - but of course you'll pay more for additional clearance.

Roof
Rigid frame metal buildings can come with several types of roofs. "Single slope" construction starts with one side wall higher than the other, and the roof simply slants from the high wall to the lower. "Peaked" or "gable" roofs have a more traditional peak, with the roof running down to both sides.

You may be able to choose the pitch of your roof, as well. Pitch is usually expressed as a ratio: 1:12 is the flattest type of roof, rising 1" for every 12" of width. 4:12 is usually the steepest pitch available for steel buildings. Increased pitch gives you more interior clearance, helps improve the building's ability to shed rain and snow, and can result in a better looking building - but also increases costs.

Arch style buildings have no distinction between roof and walls - their curved sides act as both at the same time. Some arch style steel buildings come to more of a point at the top, while others are uniformly curved, but generally they have fewer options than rigid frame buildings.

Extras
Unless your metal building is going to be an unoccupied storage building, you will need insulation. The same rating system used in residential construction is used for commercial steel buildings: R-7 is equivalent to 2" of insulation, and R-19 is 6".

An important note about insulation: if you're going to be heating and cooling the building year round, you'll save money by buying R-19 insulation. Even though it is more expensive initially, the savings in your energy bill will easily make up for the cost in just a year or two. You may also want a vapor barrier for the roof and walls, which can prevent condensation.

Other important extras include "walk doors" for pedestrians, various types of vehicle doors, windows and skylights to let natural light in, and gutters and downspouts to manage runoff. Be sure to inquire about the insulation value of the doors and windows: look for double-pane glass and insulated doors. Use BuyerZone's free steel building dealer comparison service to learn more about the add-ons you can order.

The final set of add-ons for your building are cosmetic. At a minimum, you'll be able to choose the exterior color of your building. If appearance is important, you can choose more expensive finishing options such as complete façades of wood, brick, or stucco. These options are less common, but very important to some buyers. Interior walls or partitions to make offices are built by your construction contractors, not the metal building manufacturer.