There a several different types of surface treatments for steel doors, such as primer, prepainted, woodtransfer etc. But in what circumstances we shall use a primed steel door?
In this regard, we need to start with the architectural steps.
Doors are usually started to install once the steel/wood structure is completed but before wall entirely finished. Especially hollow metal doors, for most projects, hollow metal frames will enter the construction site very early, usually when basement is completed, all the hollow metal frames will be installed onto the concrete/dry walls. It means the hollow metal doors and frames will stand longer than other doors, during the period doors may get scratched so primed paint will have a better base for repaint. Additionally, primed treatment can accept any color of painted to be done by client or anybody else.
Technically speaking, manufacturers may prefer to manufacture same time at one time as many as possible which could lower down the basic cost significantly. So we can see most doors in the market have a same size and jamb width. Thanks to standard construction opening, manufacturers could run their machine with full speed to produce the doors clients need.
With a primed paint, even if it’s not pained with finishing coat, the door still looks well if people don’t pay much attention on it, which also reduces the cost for contractors and customers.