How to Make an Outdoor Sign Waterproof: A Comprehensive Guide

Outdoor signs are a vital aspect of any business or establishment’s identity. They serve as beacons, welcoming visitors and conveying essential information. However, these signs face the constant challenge of exposure to the elements. Rain, UV rays, and fluctuating temperatures can cause significant damage if your sign isn’t properly protected. In this comprehensive guide, we’ll show you how to make your outdoor sign waterproof, ensuring its durability and readability for years to come.

Why Waterproof Your Outdoor Sign?

Before we delve into the steps to make your sign waterproof, it’s essential to understand why this is crucial. Waterproofing your outdoor sign offers several advantages:

Extended Lifespan: 

Waterproofing protects your sign from moisture-related damage, significantly extending its lifespan.

Preserved Aesthetics: 

A waterproofed sign retains its original appearance, ensuring that your branding remains attractive and eye-catching.


Preventing water damage saves you money on sign replacement and maintenance.

Enhanced Visibility: 

A well-maintained, waterproof sign is easier to read, even in adverse weather conditions.

Now, let’s get started on the process of waterproofing your outdoor sign.

Types of Outdoor Signs

The first step in waterproofing your outdoor sign is understanding its composition. Outdoor signs come in various materials, each requiring different waterproofing methods. Common sign materials include wood, metal, plastic, and acrylic. Let’s take a closer look at how to waterproof signs made from these materials:

1. Waterproofing Wood Signs

Wooden signs have a classic charm, but they are particularly susceptible to moisture damage. To waterproof a wooden sign:

Clean the Surface: Begin by thoroughly cleaning the wood surface. Remove any dirt, dust, or previous coatings.

Seal with Waterproofing Sealant: Apply a high-quality waterproofing sealant to the wood. This will create a protective barrier against moisture.

Repaint and Re-Seal: After sealing, repaint the sign with outdoor paint, and then reapply the waterproofing sealant for added protection.

2. Waterproofing Metal Signs

Metal signs are durable but can corrode over time if not properly waterproofed:

Clean the Surface: Clean the metal sign to remove rust, dirt, and old paint.

Apply Rust Inhibitor: Use a rust inhibitor on any rusty spots to prevent further corrosion.

Coat with Waterproof Paint: Apply a waterproof paint or enamel specifically designed for metal surfaces.

3. Waterproofing Plastic and Acrylic Signs

Plastic and acrylic signs are more resistant to moisture but can still benefit from waterproofing:

Clean the Surface: Clean the sign thoroughly to remove any dirt or debris.

Apply Clear Sealant: Use a clear waterproof sealant designed for plastic or acrylic surfaces.

Repeat as Needed: Reapply the sealant every few years to maintain protection.

Materials and Tools You’ll Need

Before you start the waterproofing process, gather the necessary materials and tools:

  • Waterproofing sealant or paint (appropriate for your sign’s material)
  • Sandpaper (if needed for surface preparation)
  • Rust inhibitor (for metal signs)
  • Paintbrushes or rollers
  • Cleaning supplies (soap, water, scrubbing brush)
  • Plastic sheeting or drop cloths to protect the surrounding area


To ensure a successful waterproofing job, proper preparation is essential:

Clean the Sign: Use soap, water, and a scrubbing brush to clean the sign surface thoroughly. Remove any dirt, grime, or loose paint.

Surface Smoothing: If the sign surface is rough or uneven, use sandpaper to smooth it out.

Dry Completely: Ensure the sign is entirely dry before proceeding with waterproofing.

By taking these preparatory steps, you create an optimal surface for the waterproofing materials to adhere to.

Choosing the Right Waterproofing Method

Now that your sign is clean and prepared, it’s time to select the appropriate waterproofing method. Here are some common options:

1. Waterproofing Sealants:

Waterproofing sealants come in various types, such as silicone, acrylic, or polyurethane. They create a protective barrier against moisture and UV rays.

2. Waterproof Paints:

Waterproof paints are formulated to repel water and prevent moisture from seeping into the sign’s surface.

3. Sign Covers:

For added protection, consider using sign covers made of waterproof materials like vinyl or plastic. These covers shield the sign from direct exposure to the elements.

Each method has its advantages, so choose the one that best suits your sign’s material and your desired level of protection.

Applying Waterproofing

Here’s a step-by-step guide on how to apply waterproofing to your outdoor sign:

Start with a Test Area: Before applying waterproofing to the entire sign, test it on a small, inconspicuous area to ensure compatibility and to gauge the drying time.

Apply the Waterproofing Material: Use a paintbrush or roller to apply the waterproofing material evenly over the sign’s surface. Ensure complete coverage, paying special attention to corners and edges.

Allow to Dry: Follow the manufacturer’s instructions for drying time. Depending on the product, this may take several hours or even days.

Repeat if Necessary: For added protection, consider applying a second coat of waterproofing material once the first coat is completely dry.

Maintenance Tips

To keep your outdoor sign in top-notch condition, perform regular maintenance:

  • Inspect the sign periodically for any signs of wear, such as cracks or peeling paint.
  • Clean the sign as needed with a gentle detergent and a soft cloth.
  • Reapply waterproofing material as recommended by the product’s instructions.

By following these steps and choosing the right waterproofing method for your outdoor sign, you can ensure its longevity and effectiveness. Remember that regular maintenance is key to keeping your sign looking its best. Whether you have a wooden, metal, plastic, or acrylic sign, taking the time to waterproof it properly will protect your investment and leave a lasting impression on visitors.

For more tips and guidance on outdoor signage and maintenance, explore our blog. Waterproofing your outdoor sign is a small effort that pays off with significant rewards in the long run. Invest in your sign’s future today, and it will continue to serve as a reliable ambassador for your business or message.

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