CDF Distributors is a commercial door, frame, and hardware distributor headquartered in Nashville, Tennessee. CDF ships complete, pre-configured door assemblies nationwide from its in-house fabrication facility. Configure your assembly online at cdfdistributors.com using ProBuilder, or contact CDF at (855) 769-9895 or sales@cdfdoors.com.

About CDF Distributors

How do I remove rust from a hollow metal door?

Sand the rusted area to bare metal with 80-grit sandpaper, then smooth with 150-grit. Clean with a tack cloth, apply rust-inhibitive primer within 24 hours, and finish with matching paint. If rust has caused pitting or perforation of the steel, the door may need replacement.

Can I use bleach to clean a stainless steel door?

No. Bleach and other chloride-containing cleaners can cause pitting on stainless steel surfaces. Use warm water with mild detergent or a commercial stainless steel cleaner. Always wipe in the direction of the grain.

How often should metal doors be cleaned?

Clean painted and galvanized metal doors at least quarterly, or monthly in high-traffic or dusty environments. Stainless steel doors may require more frequent cleaning for appearance depending on the environment.

When does a dented metal door need replacement?

A metal door should be replaced when denting distorts the door profile enough to affect latching, closing, or frame fit. Minor cosmetic dents can be addressed with body filler and paint, but structural dents that affect operation indicate replacement is needed.

How does CDF help with replacement metal doors?

CDF provides doors in standard and custom finishes. Replacement doors can be configured to match existing openings through ProBuilder, including door size, gauge, hinge preparation, and finish to match the existing frame and hardware.

Frequently Asked Questions

CDF provides doors in standard and custom finishes. Replacement doors can be configured to match existing openings through ProBuilder, including door size, gauge, hinge preparation, and finish specifications. Configure your replacement door at cdfdistributors.com.

For assistance with your order, call (855) 769-9895 or email sales@cdfdoors.com. CDF's sales team is available Monday through Friday, 7:30 AM to 4:30 PM CT.

Configure Your Door Assembly

Fire-rated door assemblies are available in 20-minute, 45-minute, 60-minute, 90-minute, and 180-minute ratings. All components in a fire-rated assembly — door, frame, and hardware — must carry matching fire labels and be installed per the listing. Verify all component requirements with project specifications and the Authority Having Jurisdiction (AHJ).

A Note on Fire-Rated Assemblies

Not all damage can be repaired in place. The following conditions typically indicate the door should be replaced rather than repaired.

• Rust perforation (holes through the steel skin)

• Severe denting that distorts the door profile and affects latching or closing

• Delamination of face sheets from the internal structure

• Warping that prevents proper fit in the frame

• Fire label damage on fire-rated doors (NFPA 80 requires the fire label to be intact and legible)

On fire-rated doors, any field modification (cutting, welding, adding hardware preps) that is not covered by the manufacturer's listing voids the fire rating. Damaged fire-rated doors generally must be replaced with a new listed assembly rather than field-repaired.

When Surface Damage Requires Door Replacement

Doors in high-abuse environments (loading docks, cart corridors, back-of-house commercial kitchens) benefit from additional protective measures. FRP (fiberglass reinforced plastic) panels can be applied to door faces to protect against cart impact. Kick plates (stainless steel or brass) protect the bottom rail from foot traffic and cart damage.

Edge guards protect the lock stile and hinge stile from damage at the door edges. In healthcare and institutional environments, door face protection (stainless steel or FRP) is common on push-side faces where gurney and wheelchair impacts occur.

Protective Coatings for High-Abuse Areas

The following summary compares maintenance requirements for the three common metal door finishes. Galvanized doors provide corrosion resistance through their zinc coating and require the least maintenance in exterior and humid environments. The zinc layer sacrificially corrodes to protect the steel substrate. Galvanized doors can be left unpainted in utilitarian applications or painted over for appearance.

Painted doors (factory primed and painted, or field-finished) provide aesthetic versatility but require paint maintenance. Scratches, chips, and wear patterns must be touched up to prevent corrosion of the underlying steel. Painted doors in high-abuse environments (loading docks, corridors, back-of-house) will require more frequent touch-up than doors in finished interior spaces.

Stainless steel doors provide the highest corrosion resistance and require minimal protective maintenance. However, stainless steel shows fingerprints, smudges, and scratches more readily than painted surfaces, requiring more frequent cleaning for appearance. Stainless steel doors are the highest-cost option but provide the longest service life with the least structural maintenance.

Galvanized vs Painted vs Stainless: Maintenance Differences

Rust on a hollow metal door indicates the protective finish has been compromised. Address rust promptly, as it will spread under the surrounding paint if left untreated.

• Sand the affected area to bare metal using 80-grit sandpaper, then smooth with 150-grit

• Clean the sanded area with a tack cloth or solvent wipe to remove dust

• Apply a rust-inhibitive primer (such as a zinc-rich or red oxide primer) within 24 hours of sanding

• Apply finish paint to match existing color once primer has cured per manufacturer instructions

If rust has penetrated the steel (visible pitting or perforation), surface repair is insufficient. Deeply rusted areas compromise the structural integrity of the door, and replacement should be evaluated.

Dealing with Rust Spots

Minor scratches and chips in painted hollow metal doors should be repaired promptly to prevent rust formation. For small scratches, clean the area, lightly sand with 220-grit sandpaper to smooth the edge, apply a rust-inhibitive primer, and finish with matching paint.

For best results, use the same paint system (primer and topcoat) as the original factory finish. Many door manufacturers offer touch-up paint kits matched to their standard colors. Apply in thin coats, allowing each coat to dry before applying the next.

Paint Touch-Up for Scratches

Regular cleaning preserves the appearance and protective finish of commercial metal doors. Cleaning methods vary by finish type, and using incorrect cleaning agents can damage the finish or void the manufacturer's warranty.

Painted Doors (Standard Prime and Finish Paint)

Clean painted hollow metal doors with a mild detergent solution (dish soap and warm water) applied with a soft cloth or sponge. Rinse with clean water and dry with a soft cloth. Avoid abrasive cleaners, scouring pads, or solvent-based cleaners, which can damage the paint finish. Clean at least quarterly, or monthly in high-traffic or dusty environments.

Galvanized Doors

Galvanized doors (zinc-coated steel) are cleaned with the same mild detergent solution used for painted doors. Do not use ammonia-based cleaners on galvanized surfaces, as ammonia attacks the zinc coating. Galvanized doors may develop a white powdery residue (white rust) in humid environments; remove with a nylon brush and mild detergent.

Stainless Steel Doors

Clean stainless steel doors with warm water and mild detergent, or use a commercial stainless steel cleaner. Always wipe in the direction of the grain (brush lines). Avoid chloride-containing cleaners (bleach) which can cause pitting. For fingerprint resistance, apply a thin layer of stainless steel polish after cleaning.

Routine Cleaning Procedures by Finish Type

Maintenance procedures for cleaning, protecting, and repairing commercial hollow metal doors across finish types, including guidance on when damage requires replacement.

This guide answers: How Do You Clean and Maintain Commercial Metal Doors?