How to Protect & Waterproof Outdoor Surfaces with Flex Seal Liquid

“How to Protect & Waterproof Outdoor Surfaces with Flex Seal Liquid” was written by a member of the Flex Seal Editorial Team.

Outdoor surfaces take a beating from the elements—especially during the rain-filled months. Without proper protection, moisture can seep into wood, concrete, and other porous materials, leading to damage. Flex Seal® Liquid offers a strong, flexible, watertight barrier that’s ideal for protecting and repairing outdoor furniture, planters, sheds and more.

This guide will show you how to apply Flex Seal Liquid for maximum protection and durability, along with tips to help you get the job done safely and effectively.

Key Benefits of Flex Seal Liquid

Watertight & Weatherproof – Seals surfaces against water damage.
UV & Mildew Resistant – Protects from the elements.
Flexible & Durable – Expands and contracts with temperature changes.
Easy to Apply –just brush, roll, dip, or pour it on.

Best Outdoor Applications for Flex Seal Liquid

Fixing Leaky Sheds and Roof

Rain can reveal small leaks in metal roofs or shed walls. Flex Seal Liquid seals these problem areas to help prevent further water intrusion.

How to Apply:

1. Inspect the roof for leaks and remove any dirt, rust, or debris.
2. Apply multiple thin coats with a brush or roller, covering at least 2 inches around the leak.
3. Allow 24 hours between coats and 48 hours to completely dry. Note that dry times may vary depending on temperature and humidity.

Flexpert Tip: For hard-to-reach areas, use a long-handled roller to ensure even application.

Sealing Foundation Cracks and Concrete Surfaces

Cracks in concrete driveways, patios, or basement walls can worsen with wet weather. Flex Seal Liquid provides a flexible seal that helps prevent water seepage.

How to Apply:

1. Clean cracks thoroughly using a wire brush and remove any loose debris.
2. Use a brush or roller to apply thin, overlapping coats the cracked area.
3. For deep cracks, pour Flex Seal Liquid directly into the area.
4. Allow 24–48 hours to fully cure before exposing to moisture if possible.

Flexpert Tip: Flex Seal Liquid is a final coat and cannot be painted over, but it is available in Black, White, Clear, and Gray. Make sure to select the appropriate color before application.

Waterproofing Outdoor Furniture & Planters

Patio furniture and planters often suffer from water damage, rust, and cracking due to repeated exposure to rain and sunlight. Flex Seal Liquid works on wood, metal, ceramic, plastic, and more, making it a versatile solution for sealing and protecting outdoor items.

How to Apply:

1. Clean and dry the surface before application.
2. For furniture – use a brush or small roller to apply Flex Seal Liquid.
3. For planters – brush a thin layer inside and outside the pot to prevent cracking.
4. Allow each coat to dry for 6–12 hours before applying additional coats.
5. Let cure for 24–48 hours before placing plants or using furniture.

Maintenance Tips for Long-lasting Protection

Check for cracks or weak spots after heavy storms and patch immediately.
Reapply as needed to maintain maximum protection.
Use multiple thin coats instead of one thick coat.
Store leftover Flex Seal Liquid properly – keep the lid tight and store between 60°F and 100°F for longevity.

Now is the ideal time to prepare your home before the summer heat and storms arrive. With Flex Seal Liquid, you can get your property ready for the rain with ease.