Prefinished steel door frames.

INTRODUCTION

HANGING A DOOR DEPENDS ON THE PROPER INSTALLATION OF THE DOOR FRAME. Door frames consist of three primary parts: the strike jamb, the hinge jamb, and the header. The strike jamb has the strike and deadbolt preparation formed into it. The hinge jamb is prepared to accept the hinges, and the header is formed to fit to the jambs. The door stop is formed into the jamb at the factory and, if weather stripping is to be installed, a pocket, called a kerf, can be formed into the jamb to accept the weather stripping. The metal frames are then shipped, ready for installation and few, if any, modifications are made on the job site.

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Building codes require fire door assemblies in commercial buildings such as offices, industrial facilities, hospitals, and schools, and a steel frame with a fire door is a good way to meet these requirements. Fire-rated openings are made up of a frame, door and hardware. Frames are usually rated from 20 minutes to 3 hours with the fire rating the total opening determined by the lowest rated component. For example, using a 20-minute-rated door with a 90-minute-rated frame and hardware results in a rating of 20 minutes. The fire rating is embossed on the hinge jamb.

Metal frames come in a variety of designs. Most are made in an unequal rabbet style with the frame being formed so that either a 1 3/4 or 1 3/8 door can be prepped into the frame. They also are available in equal rabbet frames so that two doors of the same size can be hung into the frame. Equal rabbet frames are usually used between two hotel rooms. They can also be made in single rabbet frames, which are generally used when the designer wants a no stop look.

History of Steel Frames:

Over the last 100 years there have been a lot of changes in steel frames. They started as flat metal welded into the wall with stops welded onto them. Most of the time the hinges were surface applied to the frame.

Press-broke hollow metal frames were the next type of steel frame to be developed. At the end of World War II contractors started using drywall. Using slip in anchors, hollow metal frames where adapted to this new type of wall

With the advent of drywall construction a new type of steel frame was developed--"Prefinished Steel Door Frames." These frames were designed to be installed over the drywall at the end of the project.

HOLLOW METAL FRAMES

Hollow Metal or HM frames are usually made from 16-gauge steel, with 14- and 18-gauge available. If the frame is assembled by the distributor, it is referred to as a welded door frame. Welded frames are delivered to the jobsite for installation during wall construction without the doors. If the frame is assembled at the job site or installed during wall construction, it is referred to as a knockdown door frame or KD frame. One type drywall HM frame can be installed after the sheetrock is in place using compression anchors. Hollow metal frames are field painted.

PREFINISHED STEEL DOOR FRAMES

Prefinished frames are usually made from 20-gauge steel with 18-gauge available. The frame is cleaned, primed and painted with a finish coat by the manufacturer and assembled at the job site.

ADVANTAGES OF PREFINISHED STEEL DOOR FRAMES

Prefinished frames are not Hollow Metal Frames. Installing a prefinished frame during the finish phase of the project reduces the possibility of damage to the door unit. Frames, doors and hardware can be shipped to the project later, allowing more time to coordinate each item so fewer mistakes are made in preparations. Prefinished steel door frames come in both standard and adjustable profiles and are available with a kerf, for the installation of weather stripping. Prefinished steel door frames are available with any size sidelite, transom or borrowed lite unit. They are designed to be installed after a wall is built and all painting and other wall finishes are completed. Masking around the door frames is not necessary because both the frame and wall are finished. When using vinyl wall coverings, the covering is cut to the rough opening and the frame is sleeved over the wall covering. No calking is required around the frame. Prefinished frames can be installed over floor coverings, eliminating the need to cut the flooring to fit around the frame. Doors and finish hardware are installed at the same time as the prefinished steel frame, rather than in separate stages like hollow metal frames. Doors can be pre-hung using an adjustable frame or hung while installing the frame. The door is used like a square frame template to help check the frame for plumb, square and twist.

CASINGS

Casings are used to conceal the screws that are used to install prefinished steel frames. There are three types of casings available from the manufacturer: Standard Steel, Colonial Steel, and Aluminum. Factory casings are snapped on to tabs on the frame. Wood trim can also be installed over prefinished steel door frames instead of the factory casings. To use wood trim, the prefinished steel door frame is ordered without tabs and casings to provide a flat surface for the trim. Fire ratings of prefinished frames are not affected by the use of different casings. For example a 90-minute-rated frame can use jobsite wood trim.

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When a prefinished frame is installed at the end of the project, there are a number of ways that savings are obtained. The largest savings is achieved by not having to field paint the frames. Field painting of frames costs at least $65.00 per opening. Because the installation of the frame, door and hardware is done at the end of the project, a number of man hours are saved. All the contractor has to do is leave the correct sized rough opening and all sheetrock work, plumbing, electrical, painting and wall coverings are completed before the prefinished frames, finished doors and finish hardware are installed. Time savings are obtained by not having to get hollow metal frames to the job during wall construction. Painting of the wall is completed without masking around the frames. Sheetrock is cut to the rough opening not pushed behind the frame. Wall coverings are completed before frame installation, not cut around the frame, so calking around the frame is not required. This adds up to around $120.00 per installed opening savings over hollow metal frames.

Preparation for Installation of Prefinished Steel Frames

Prefinished steel frames are shipped ready to install and modifications should not be attempted in the field. Both the components and the boxes in which they are shipped are marked to help with assembly and installation instructions are placed in each header box by the manufacturer.

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A few necessary steps must be completed before starting the installation of prefinished steel door frames. First verify that all of the door opening components, frame, doors, hardware, and hardware reinforcements are on hand. The parts must be located and placed by the opening. Because the frame, door and hardware are all installed at the same time, any problems will be discovered while installing the first door, rather than after several frames have been installed.

The rough openings for Prefinished Steel Door frames are different than other types of frames. For single and paired door frames, it is 1 1/4" in width over door size and 1" in height from finish floor over door height. For side lite frames it is 1 1/4" plus door, plus glass size and 2" for each mullion in width and 1" in height. For borrowed lite windows it is 1 1/4" plus glass and mullions in width and height.

Measure the wall to make sure the frames are the correct size. The width of the frame should be exactly the same as the finished wall thickness or up to 1/8" wider. If the frame is smaller than the wall, installing it over the wall will cause the frame to spread. This will change the shape of the frame, affecting the swing of the door and preventing it from closing properly. For example if the wall is designed to be 4 7/8" you should order a 4 7/8" or 5" frame.

Frame components should be secured with drywall screws. Finish screws are used to install the frame only when job site wood trim is to be used.

Reinforcements for hardware are required for prefinished steel door frames. They are metal formed to fit into the backside of the prefinished steel door frame and are used behind parallel arm door closers, rim exit devices, overhead door holders, and any other type of hardware that will attach to the frame. Check with the manufacturer to see where reinforcements are required and install them as needed. If they were not provided with the prefinished steel door frame, they must be obtained before the frames are installed. If hardware reinforcements are not installed before beginning installation of the frame, the screws holding the finish hardware will come loose and damage the frame. If it is a fire rated frame and the reinforcements are not used, the fire rating of the frame is voided.

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Prefinished steel door frame components are a finished product and must be handled carefully to avoid scratching the paint or denting the frame. They must be installed at the finishing stage of the job to prevent damage from moving materials.

Installation of Standard Prefinished Door Frames

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TOOLS REQUIRED

* Screws

** Finished screws are used when job site wood trim is used

** Standard drywall screws are used on most installations.

* Level

** 2' and 6' magnetic

* Screw gun, usually cordless