Before we discuss the preparation of the surface let's look at what you are trying to achieve:

Repainting or Clear-Coating?

Your approach to refinishing your door may depend in part on the condition of your door and whether you're considering repainting or simply applying a clear coat.

Clear-Coating

If you want to restore the door's shine and enhance its existing color—and the door is in good condition aside from some dirt, chalk, or minor scratches without adhesion issues—clear-coating is a good option. Start by using Zap-It! as detailed in the following sections and in the Zap-It! Application Guide. After cleaning, follow the instructions to apply your clear coat.

For minor scratches, we have touch-up paint available in our store.

Visit Roll-Up Door Touch-Up Paint

Repainting

If you’re changing the door's color and the existing surface is glossy, you should still use Zap-It! as specified. However, you’ll also need to abrade the surface to create a proper profile for the new paint to adhere. We offer a selection of brushes and other materials to help with the abrading process.

We cannot emphasize enough the importance of proper surface preparation. We recommend reviewing the articles linked at the end of this section to understand the challenges and see multiple examples of paint failures caused by inadequate or absent surface preparation.

Doors with Paint Failure

If the door is so chalky that using Zap-It! exposes bare metal or leaves the remaining coating too thin, you’ll need to repaint. This can happen if the door has been left to oxidize without protective coatings.

Finally, if the door has peeling, cracking, or other types of paint failure, these issues must be addressed before repainting.

We recommend reading the following articles, and if you need further advice, feel free to reach out to us—we’ll be happy to point you in the right direction.

• Anatomy of a Self-Storage Roll-Up Door - A Primer for Painters
• Paint Failure Part 1: Diagnosing the Root Causes
• Part Failure Part 2: Other Causes, Testing & Wrap-Up

Preparing the Roll-Up Door

The process of cleaning SMP (Silicone Modified Polyester) coated surfaces is crucial for ensuring optimal adhesion of the new coating. Follow these basic steps when you are preparing to paint or clear coat:

Note: While this example focuses on a roll-up door, the basic principles apply equally to metal panels and other SMP-coated metal surfaces.

Pre-Rinse the Area

• Use a power washer to thoroughly pre-rinse the surface.
• Spray in a back-and-forth motion, keeping the nozzle perpendicular to the substrate.
• Be cautious not to allow water to get behind the curtain, especially when pre-rinsing storage doors.

Rinse the door and allow it to dry before applying Zap-It (click for full guide)

Apply Zap-It! Chalk & Grime Buster:

• After pre-rinsing, apply Zap-It! to a completely dry door using a medium brush and pole.
• Scrub the substrate vigorously, focusing on the profile of roll-up doors, inside corners, seams, and areas around the top, bottom, and lock.
• For hard-to-reach areas, use a coarse scotch-brite pad to ensure thorough abrasion.

Click here to view brush and surface prep products

Use a soft RV-style brush to loosen the chalk and grime for best results (click for full guide)

Rinse and Inspect:

• Once the surface is sufficiently abraded, use the power washer to carefully rinse off all the Zap-It!, dirt, and any paint residue.
• Inspect the area to ensure the SMP coating has been adequately cleaned, dulled, and scratched.
• If any areas remain glossy, repeat the process until the entire surface is uniformly clean and dull.

Completely rinse the door (click for full guide)

Key Considerations:

• Outcome Over Process: The most critical aspect is achieving a clean, dull, and scratched substrate. Repeat the process as necessary to obtain an acceptable profile for coating application.

Pro Tip: Adhesion Testing: 

Before starting any paint job, you should evaluate the condition of the door, look for areas of failing paint and determine whether adhesion testing is warranted. If you didn’t test then, you may discover problem areas when you are cleaning and abrading the doors and you’ll need to address them. Painting over failing paint will not fix the problem, in fact it may worsen it by further stressing the old paint. 

Additional Resources:

• Zap-It Application Guidelines (pdf) - The complete guide for applying Zap-It! Read it before using.
• Zap-It! Product Page - Visit the store page to see more product information or order the product
• Anatomy of a Self-Storage Roll Door: A Primer for Painters - Offers detailed insights into the challenges of painting roll-up doors, supported by various paint manufacturers' technical sheets that emphasize the critical importance of proper surface preparation for Silicone Modified Polyester (SMP), Kynar and other slick surfaces.
• Coil Coated Steel: Revolutionizing Self-Storage Construction - A bit of background on silicone modified polyester (SMP).
• The Paint Files - A collection of documents from our archive which may provide other useful information.

Zap-It Chalk & Grime Buster

Powerful chalk remover and cleaner for door refinishing prep work.

• Removes chalk (oxidized paint), grease and grime in preparation for refinishing roll-up doors
• Cuts through chalk and grease to make prep work faster
• Economically priced

Learn More

Disclaimer: The information provided in the Self-Storage Learning Center is for general informational purposes only. While we strive for accuracy, All From 1 Supply makes no guarantees regarding the completeness or reliability of the information. Use of this content is at your own discretion, and we encourage independent verification before making decisions based on the material.

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