Insulated metal panels (IMPs) are designed to deliver exceptional thermal efficiency, structural integrity, and aesthetic appeal for decades. But even the most durable wall or roof system isn’t completely maintenance-free.

Routine cleaning is one of the simplest and most effective ways to protect your investment and extend the life of your panels. It helps maintain the integrity of the protective coating, improves appearance, and supports overall building performance—especially in demanding environments like cold storage facilities, food processing plants, and industrial warehouses.

“A building may start to look old or dull even though it still has a long life left. Often, the only thing the building needs is cleaning,” explains U.S. Steel in its construction bulletin on painted metal building maintenance.

Why Cleaning Matters: More Than Just Curb Appeal

IMPs are finished with high-performance coatings like Kynar 500® (a type of PVDF/fluoropolymer) or Valspar’s fluoropolymer, silicone polyester, and polyester coatings.

These coatings are engineered to resist corrosion, UV degradation, and airborne pollutants. However, over time, even the most advanced finishes will begin to chalk, collect dirt, and develop biological growth if left uncleaned.

“Polyester coatings are resistant to many elements such as air pollution, acid rain, and general airborne dirt,” says Valspar’s cleaning and maintenance guide.

Cleaning IMPs on a regular schedule offers multiple benefits:

• Preserves Finish Integrity: Prolongs the life of the coating by removing harmful residues
• Maintains Color & Gloss: Prevents dulling from chalk, oxidation, and dirt buildup
• Improves Hygiene: Reduces biological growth in humid or shaded areas
• Prevents Staining: Eliminates rust streaks, mildew, and sealant residue before they become permanent
• Supports Warranty Compliance: Some panel warranties require regular maintenance to remain valid

What Causes IMPs to Get Dirty?

Several common environmental and jobsite-related factors contribute to soiling or staining of metal panels:

Environmental Factors

• Airborne Pollution: Soot, dust, and organic matter can settle and cling to panel surfaces.
• UV Exposure: Long-term exposure can lead to chalking, which produces a white, powdery residue.
• Biological Growth: Mold, algae, and mildew thrive in damp or shaded areas, particularly on north-facing walls.
• Water Runoff: Hard water deposits or contaminants from adjacent materials may cause streaks or stains.
• Climate Conditions: Humid or coastal climates accelerate corrosion risks if debris is not removed promptly.

Construction-Related Factors

• Steel Debris: Shavings or filings left on the panel surface can rust and cause discoloration.
• Excess Sealants, Mortar, or Paint: Residues from nearby construction can harden and stain panels.
• Graffiti: Unwanted markings require special removal techniques to avoid damaging the finish.

How Often Should You Clean IMPs?

Cleaning frequency depends on environmental conditions, building use, and geographic location. Consider the following schedule:

In general, an annual visual inspection is recommended. If panels show signs of chalking, mildew, dirt accumulation, or streaking, cleaning should be performed promptly.

Cleaning Do’s and Don’ts: Protecting the Finish

Before beginning any cleaning process, keep the following rules in mind:

✅ Do:

• Start with the mildest cleaning method.
• Use soft cloths, sponges, or non-abrasive brushes.
• Rinse all surfaces thoroughly to remove residue.
• Test all solvents or detergents on an inconspicuous area first.
• Follow the coating manufacturer’s guidelines if available.

🚫 Don’t:

• Use wire brushes, scouring pads, or steel wool.
• Allow harsh chemicals to sit on the surface for extended periods.
• Mix incompatible cleaners (e.g., acids and bleach).
• Clean in direct sunlight or on hot surfaces, which can cause streaks.

Step-by-Step Cleaning Methods for IMPs

Step 1: Water Rinse

Start with a simple rinse using clean water from a hose or low-pressure washer. This helps remove loose dust, dirt, and environmental residue.

• Use a wide spray angle.
• Maintain 12–18 inches of distance from the surface.
• Avoid forcing water into panel joints or insulation seams.

Step 2: Mild Detergent Cleaning

If dirt remains, mix a solution of 5% mild detergent (such as dish soap or powdered laundry detergent) with water.

• Apply using a soft cloth, sponge, or long-handled brush.
• Gently scrub in a circular motion.
• Rinse thoroughly with clean water to remove all soap.

This method is safe for all coating types and is typically sufficient for general cleaning.

Step 3: Solvent-Based Cleaning (Use With Caution)

For tar, grease, adhesives, or graffiti, solvents may be required. Always handle with proper ventilation and personal protective equipment (PPE).

Approved solvents (use for ≤5 minutes of contact):

• Alcohols: Isopropyl or denatured alcohol
• Mineral Spirits: For oil or tar residues
• Xylene / Toluene: Stronger solvents for graffiti or stubborn stains (test first)

Avoid acetone, lacquer thinner, and other aggressive paint removers unless you’re prepared for potential damage or recoating.

Removing Specific Contaminants

Mildew or Mold

For mildew-prone areas (shaded, humid zones), use a bleach-based cleaner:

• 1/3 cup powdered laundry detergent.
• 1 quart household bleach (5% sodium hypochlorite).
• 3 quarts warm water.

Apply with a sponge or soft brush. Allow 5–10 minutes of contact time, then rinse thoroughly. Never mix bleach with other cleaners like ammonia.

Rust Stains

Surface rust may result from residual steel debris or contact with untreated fasteners. To clean:

• Use a solution of citric, oxalic, or hydrochloric acid diluted 1:10 with water.
• Limit contact to 5 minutes.
• Rinse thoroughly and inspect the coating.

Always neutralize acid residues and test first. Wear gloves and eye protection.

Graffiti

Graffiti removal requires a progressive approach:

1. Soap and water.
2. Mineral spirits or isopropyl alcohol.
3. Commercial graffiti remover (check coating compatibility).
4. If damage persists, repaint or replace the affected panel.

Long-Term Maintenance Tips

• Schedule regular cleanings based on your building’s environment and exposure.

• Document cleaning activities for warranty and facility management records.

• Avoid landscaping practices that trap moisture near panel bases.

• Promptly clean bird droppings or decaying organic matter to prevent staining.

• Use color-matched touch-up paint only if the surface has been scratched or abraded.

Preserve Your Panels, Protect Your Property

Insulated metal panels are a high-value construction solution—but like any building system, they require periodic care. Routine cleaning:

• Boosts performance and longevity.
• Protects coatings from premature wear.
• Keeps your building looking professional and well-maintained.

Whether you’re managing a food facility, manufacturing plant, or climate-controlled warehouse, your panels work hard every day. Give them the maintenance they deserve—and ensure your investment lasts for decades.

Want expert insight into panel care or coating systems? Contact Green Span Profiles today to learn more about our high-performance insulated metal panels and support services for cold storage and commercial buildings.