Steel doors and frames in plain terms
Most back doors, service entries and stairwell doors on commercial buildings are hollow metal doors. Each is two steel faces wrapped around a core, with steel edges closing it in.
The core might be honeycomb, foam insulation or steel ribs, depending on where the door goes. Inside, the door has thicker steel at the hinges, lock and closer so screws have something solid to bite into.
Steel thickness is described by gauge, and a lower number means thicker steel. Exterior doors are often galvanized, with a zinc coating under the paint that slows rust.
Doors are also built, or "prepped," for a specific set of hardware. That matters when you change locks or add an exit device later.
Frame types
The frame is the steel outline the door hangs in. It has a raised strip, called the stop, that the door closes against.
- Knock-down frames: shipped in pieces and assembled in the opening, common in interior drywall walls.
- Welded frames: welded at the corners before they reach the site. They are more rigid and are often set while a masonry wall goes up around them.
- Frames in existing openings: fastened through the jambs with anchors into a finished wall.
- Frames on metal buildings: fastened to the steel framing around the opening, with wall panels trimmed to fit.
Whatever the type, a door only works as well as its frame is square and anchored.
The hardware on a commercial door
The hardware set is everything mounted on the door and frame. Each piece has one job, and when one fails, it puts strain on the others.
Hinges
- Butt hinges: two leaves joined by a pin. Ball-bearing butt hinges hold up better on heavy doors with closers.
- Continuous hinges: one hinge that runs the full height of the door. It spreads the weight along the edge, which helps heavy doors and doors whose hinge screws have stripped out.
Closers
A closer is a hydraulic arm that pulls the door shut and controls its speed. Most have separate adjustments for swing speed, latching speed and backcheck, which slows the door if it is thrown open or caught by wind.
A closer that leaks oil has usually reached the end of its life, since the fluid can't simply be topped off.
Locksets
- Cylindrical locksets: installed through round holes bored in the door. They are simpler and common on offices and interior doors.
- Mortise locksets: a box-shaped lock body set into a pocket in the door edge. They are heavier, offer more functions and stand up better to constant use.
Exit devices
An exit device, often called a panic bar, unlatches the door when someone pushes the bar from inside.
- Rim exit devices: mounted on the face of the door, with a latch that catches a strike on the frame. This is the most common type on single doors.
- Vertical rod exit devices: rods run to latches at the top and bottom of the door. They are used on pairs of doors that meet without a center post.
- Mortise exit devices: paired with a mortise lock body in the door edge for a sturdier latch.
Stops, plates and seals
- Stops: wall, floor or overhead stops keep the door from swinging too far and tearing at the hinges, closer and wall.
- Plates: besides standard kick plates, taller armor plates and edge guards protect doors that pallet jacks hit often.
- Thresholds: the metal saddle across the floor of the opening. It gives the door a surface to seal against and smooths the step for carts and wheelchairs.
- Sweeps: a rubber or brush strip on the bottom of the door that blocks water, dust, insects and rodents.
- Weatherstripping: a gasket along the frame stop that the door presses into when it closes.
Astragals on pairs of doors
An astragal covers the gap where two doors meet. When it overlaps, the doors must close in order, so many pairs use a coordinator that holds the active door until the inactive one has closed.
Why commercial doors fail
Most door problems start with everyday use and a little abuse:
- Wind: a gust that catches an outswing door can bend the closer arm, stretch the hinges or spring the frame.
- Propping: wedging a door open against a working closer strains the closer and its mounting screws.
- Carts and pallet jacks: impacts dent the bottom of the door, bend vertical rods and knock bottom latches out of line.
- Pulling on the lever: doors without a pull handle get yanked open by the lever, which leaves it sagging.
- Loose screws: slamming backs out screws in hinges, closers and exit devices.
- Debris: grit packed into a bottom rod latch or the threshold can keep the door from latching.
- Building movement: when a slab or wall shifts, the frame goes out of square and the door starts rubbing.
Security upgrades for back doors
Back doors face alleys, loading areas and parking lots, out of sight from the street. A few general upgrades make a door harder to force:
- Latch guards: a steel plate that covers the gap between the door and frame at the latch, so a pry bar can't reach it.
- Sturdier hinges: heavier hinges, and on outswing doors, non-removable pins so the door can't be lifted off from outside.
- Better frame anchoring: a frame that flexes in the wall can be pried away from the latch. Added anchors close that weak spot.
Any upgrade on an exit door still has to let people out freely from inside. If a door is fire rated, check with your fire marshal before adding plates or hardware.
Exit doors must always open freely
After a break-in, or when employees keep using a back door as a shortcut, it's tempting to chain it shut. Don't.
Never chain, padlock, bar or block an exit door, even after hours.
People need to get out in an emergency, and a blocked exit can trap them. If a door keeps getting propped or left unlatched, the fix is in the hardware, such as a closer that latches reliably or a better strike. Ask your fire marshal what is allowed on your exit doors.
Fire-rated doors
Some doors, such as stairwell and corridor doors, may be fire rated. A rated door and frame are built and tested to hold back fire, and they carry a label on the edge of the door and on the frame.
Rated doors have their own inspection requirements, and changes like drilling new holes or swapping in unrated hardware can affect the rating. Ask your fire marshal, building official or insurer what applies to your doors.
If you think a door is rated, tell us before we start and send a photo of the label if you can find it.
Rust, storms and North Texas soil
Spring storms drive rain sideways under doors, hail dents the faces, and summer sun bakes doors that face south and west.
Rust starts where water sits: the bottom edge of the door, the base of the frame and scratches in the paint. A sidewalk that slopes toward the building or a sprinkler that hits the door speeds it up.
North Texas clay soil also shrinks in drought and swells after rain, which can shift a slab enough to move a frame. A door that closes fine in spring may rub by late summer.
A few habits help:
- Touch up chipped paint before rust takes hold.
- Replace torn sweeps and worn weatherstripping.
- Keep the caulk between the frame and the wall sealed.
- Aim sprinklers away from doors and keep soil off the base of the frame.
What a service visit looks like
When you call, we'll ask which door it is, what it's doing and how the building uses it.
On site, we look at the whole opening, not just the part that broke. We work the door several times, check the gaps around it, look over every piece of hardware and make sure the frame is solid in the wall.
Then we explain what we found and your options. When we have the parts with us, we can often make the repair on that visit. When a new door, frame or special hardware is needed, we measure and order it.
Before we leave, we let the door close from full open to confirm it latches on its own, and we check that the exit hardware releases with a normal push.
How we decide between repair and replacement
The frame comes first. If it's solid, square and anchored, most of what hangs in it can be fixed on its own. If it isn't, new hardware won't stay adjusted for long.
Next we check whether the steel at the hinges and lock is sound, and whether the hardware you want fits the existing preps. Putting a mortise lock in a door prepped for a cylindrical lock isn't always practical.
We also weigh how the door is used. A light interior door hung on a busy delivery entrance may never hold up, no matter how well it's repaired.
For rated doors, new parts have to suit the rating, which can narrow the options. Either way, we explain the choice and leave the decision to you.
Commercial doors we work on around DFW
Each kind of building puts its own demands on a door:
- Warehouses: walk-through doors beside the dock take forklift traffic, wind and dust. If the big doors need work too, see our commercial overhead garage doors page.
- Offices: suite entries, stairwells and interior doors get steady traffic, and quiet, reliable latching matters to tenants.
- Churches: doors may sit mostly unused during the week, then take crowds on Sunday. Pairs of doors with exit devices are common.
- Multi-tenant buildings: every suite has a back door, and it isn't always clear whether the owner or tenant handles repairs. We work with owners, tenants and property managers alike.
- Service entries: restaurant and retail back doors handle deliveries, trash runs and carts all day. Kick plates, strong closers and sturdy hinges earn their keep here.
For the glass doors out front, see our commercial storefront doors and automatic entry doors pages.
From our main location in Bells, we serve Dallas, Sherman, McKinney, Frisco, Forney and the towns between.
What affects the cost
- Scope: hardware only, a new door in the existing frame, or a full door and frame.
- Door build: size, steel gauge, core, galvanizing and any glass.
- Single door or pair: pairs need more hardware, including astragals and sometimes coordinators.
- Hardware type: mortise locks and vertical rod devices cost more than cylindrical locks and rim devices.
- Fire rating: rated doors, frames and hardware cost more than unrated ones.
- Wall type: setting frames in masonry takes more work than in drywall or a metal building.
- Access: tight spaces, occupied buildings and after-hours work.
Once we've seen the door, we can price the work for you.
How to get started
Call us at (903) 294-1846, Monday to Saturday from 7 AM to 5 PM, or send a request. You can also email prodoorsandgates@gmail.com.
If a door won't lock or an exit won't open, emergency service is available by appointment after 5 PM Monday through Saturday and on Sundays.
Tell us the address, which door needs work and what it's doing. Photos of the whole door, the hardware and any label on the edge help.
Pro Doors and Gates is family owned and based in Bells. We'd be glad to help keep your doors working.
