Outdoor signs are a great way to advertise your business, display important information, or share creative messages. However, since these signs are exposed to the elements, it’s crucial to make them waterproof. A waterproof outdoor sign will withstand rain, snow, and other wet conditions without fading, peeling, or sustaining other types of damage.
Making an outdoor sign waterproof may seem complicated, but it can actually be simple with the right products and techniques. In this comprehensive guide, we’ll walk you through all the steps and considerations for creating a fully waterproof outdoor sign that will hold up beautifully against the forces of nature.
Choose Appropriate Materials
The first step in creating a waterproof sign is selecting the right materials. The sign substrate, paints/inks, and coatings all play a role in water resistance. Here are some good options to consider:
Metal
Metal is one of the most waterproof sign materials available. Stainless steel and aluminum, in particular, will not warp or rot when exposed to moisture over time. Metal signs can also be coated for extra protection.
High-Density Plastic
Plastics like PVC and acrylic are naturally water-resistant and won’t degrade outdoors. High-density plastics will be the most durable. Look for UV-stabilized plastic to prevent sun damage.
Marine Grade Plywood
Though wood seems like a questionable choice, marine plywood is actually engineered for water exposure. It has a durable adhesive and won’t easily delaminate. For even more protection, coat the edges with polyurethane.
Aluminum Composite Material (ACM)
ACM panels have aluminum exterior faces sandwiching a polyethylene core. This construction makes ACM signs very rigid and weather resistant. Popular trademarked ACM products include Alucobond, Reynobond, and Dibond.
Avoid paper, cardboard, and natural wood
While cheaper, these porous materials will quickly deteriorate outside. Only use high-quality, specially treated materials designed for outdoor use.
Use Weatherproof Paints/Inks
For painted or printed signs, choose paints and inks made specifically for outdoor use. Look for:
- Exterior latex paint – More flexible and fading/mildew resistant than interior paint
- UV-resistant inks – Won’t fade as quickly in sunlight
- Solvent-based inks – Bond well and are waterproof on most surfaces
- Marine grade paint – Formulated to withstand wet environments
- Automotive paint – Highly durable for outdoor use
Avoid cheap craft/indoor paints and inks – they will peel and fade when exposed to the elements. Invest in quality exterior-grade coatings.
Apply a Clear Protective Coating
After painting or printing your sign, it’s highly advisable to apply a clear topcoat to protect the design and provide additional waterproofing. Some good options:
- Polyurethane – Waterproof and durable; ideal for wood signs
- Exterior varnish – Also great for wood signs; opt for vinyl varnish for best moisture resistance
- Powder coating – Very tough; often used on metal signs
- Automotive clear coat – Gives a glossy, water-resistant finish
- Laminate – Plastic film layer; choose exterior-grade laminate for printed signs
Apply 2-3 coats of your chosen finish, allowing proper dry time between coats. This will seal and armor the sign against rain.
Use Weatherproof Hardware
All of the screws, bolts, adhesives, and other hardware used on your sign should also be weatherproof. Here are some tips:
- Use exterior-grade screws and fasteners made of stainless steel or rust-resistant aluminum.
- Choose a waterproof adhesive like exterior-grade silicone or construction adhesive.
- Fit keyhole slots with rubber washers to create a watertight seal.
- Prevent pooling water with angled cuts or weep holes.
- For pole-mounted signs, select watertight mounting hardware.
Take time to properly seal all edges, joints, and hardware connections on your sign. This prevents moisture seeping in.
Additional Tips for Waterproofing Signs
Here are some other best practices to help make your outdoor sign impervious to the elements:
- Perform regular maintenance by checking for damage, cleaning, and reapplying protective coatings as needed. This will maximize longevity.
- Direct rain away from the sign’s face with peaked, angled, or umbrella-shaped designs. This minimizes exposure.
- Allow for proper drainage so water doesn’t pool on the sign. Drill small weep holes if needed.
- Use a drip edge – a thin protruding lip that forces runoff away from the sign’s surface.
- Elevate signs off the ground with legs or posts. This prevents splashing up from puddles and allows air circulation.
- Avoid applying vinyl decals or wraps outdoors. Vinyl is not very waterproof and edges may lift. Use UV-resistant paints instead.
With the right planning and materials, your outdoor sign can withstand all types of wet weather. Just follow these tips!
Frequently Asked Questions About Waterproofing Outdoor Signs
How do you waterproof an outdoor sign?
Waterproof an outdoor sign by using weather-resistant substrate materials like metal, marine plywood or high-density plastic; exterior-grade paints/inks and protective coatings like polyurethane or epoxy; and stainless steel hardware. Perform regular maintenance to maximize longevity.
What is the most waterproof material for outdoor signs?
Metal and plastic are the most inherently waterproof sign substrate materials. Metal signs like stainless steel or aluminum resist corrosion and won’t warp. High-density plastics like PVC and polyethylene are also great waterproof options.
Can I use cardboard for an outdoor sign?
No, cardboard is not suitable for outdoor signs. It will quickly deteriorate as it absorbs moisture. Only use thick, rigid, weather-resistant sign substrates designed specifically for outdoor use.
How do you protect painted signs from rain?
Protect painted outdoor signs from rain by using exterior-grade latex paints and applying 2-3 coats of a clear polyurethane, varnish or automotive clear coat. Perform regular touch-ups as needed to maintain protection.
Should I laminate my outdoor sign?
Yes, laminating with an exterior-grade vinyl film will add good waterproofing and UV protection. Use a high-quality laminate and apply properly from edge to edge to prevent moisture intrusion.
How often should I re-coat my outdoor sign?
It’s best to reapply a clear protective coating to your outdoor sign about once a year, or whenever you notice signs of damage or wear. This maintains the waterproof seal. Proper prep work is key for good adhesion.
What prevents plywood signs from warping?
Sealing the edges and back of a plywood sign with polyurethane or epoxy resin can help prevent moisture penetration that leads to warping. Use marine grade plywood for greater durability. Apply exterior paint/primer to all surfaces before adding designs.
Can I use spray paint on outdoor signs?
Yes, you can use spray paint on outdoor signs as long as it is formulated for exterior use and you apply a clear coat for added protection. Enamel spray paints bond well and provide good coverage on most sign materials. Proper prep and priming is always key.
Making your outdoor signs waterproof is crucial for longevity and durability against the elements. Following these tips will help your signs stay looking great rain or shine!
Conclusion
Creating weatherproof outdoor signs may involve a few more steps and specialty materials, but the extra effort is well worth it. When constructed properly using water-resistant substrates, paints, hardware and protective coatings, your signs will be able to withstand exposure to rain, snow and humidity for years to come.
The most important things to remember are:
- Select substrate materials specifically designed for outdoor use, like aluminum, treated wood, or heavy duty plastics
- Use only UV and weather-resistant paints, inks, and coatings to decorate the sign
- Apply a clear topcoat like polyurethane or automotive clear coat for extra protection
- Choose stainless steel or other waterproof mounting hardware
- Perform regular inspections, maintenance and touch-ups as needed
With attention to detail and the right products, it is definitely possible to create a fully waterproof outdoor sign that maintains its integrity and appearance over time. Just be sure to do your homework and implement best practices at each stage of the process – from design and materials selection to fabrication, mounting and upkeep. A weatherproof sign is a smart investment that will effectively promote your brand, business or message for years to come.