How To Seal a Wood Fence With Flex Seal Liquid

This “how to seal a wood fence” blog was written by a paid contributor. All images by Briana Colangelo.

Is there an area around your home that needs a little TLC? For me, it was the old wooden fence around our front yard. This weathered fence had certainly seen better days, and it was bringing down the curb appeal of our home.

We contemplated purchasing an entirely new fence, but with rising costs, it just wasn’t feasible. Instead, we decided to sprinkle some DIY magic to save our current fence. Thanks to Flex Seal Liquid, I was able to refresh and waterproof our fence to give it another life!

Read on, and I’ll teach you how to waterproof a wood fence using Flex Seal Liquid.


● 1 Flex Seal Liquid gallon, clear

● Power washer or scrub brush

● Wood stain (optional)

● Stain & waterproofing brush

● Paint roller and tray

● Gloves

Note: Use caution when working with power tools and always follow manufacturer’s instructions. Before using Flex Seal products, read all directions and take proper safety precautions, such as being in a well-ventilated area and wearing protective gear while applying.


1. Prep the Fence

My fence was in rough shape because it spent many years without having stain or sealant on it. So, the first thing I did was use my power washer to remove years of dirt and grime. Flex Seal Liquid is best applied on a clean surface, so it’s important that you do not skip this step. If you don’t own a power washer, you can rent one from a local hardware store or use a scrub brush to clean the wood.

Flexpert Tip: Be careful when power washing an already stained fence. The power washer can strip the stain off of it, which we do not want to happen. If your fence is already stained, a light scrub and wash should do the trick. Allow your fence to dry fully before moving on to the next step.

2. Add Stain: (optional)

Now that my fence is clean, it’s time to apply some stain. I used a paint roller to apply a semi-transparent waterproofing deck stain in the color “Tugboat.”

Be careful not to roll too fast while applying, or you might get stain all over yourself. After using the paint roller, I returned with my stain & waterproofing brush to get the stain into all the nooks and crannies of the fence. Allow the stain to dry for a full 24 hours before moving on to the next step.

Flexpert Tip: If you don’t want to stain your fence but would like to add a pop of color, Flex Seal Liquid is also available in black, white, and gray!

3. Seal Fence With Flex Seal Liquid

Flex Seal Liquid makes a great wood fence sealant because it is UV resistant and waterproof. The application process was similar to staining, except I used a foam roller to apply the product. The foam roller was compact enough that it allowed me to get into all the small areas of the fence.

Flexpert Tip: After applying the first coat of Flex Seal Liquid, allow 24-48 hours for it to fully dry before adding additional coats.

I’m so impressed with how our fence turned out — it’s no longer the eye sore of our front yard! We also saved a whole ‘lotta money by deciding to refresh our fence instead of replacing it. With some stain and Flex Seal liquid, I now feel confident our fence will survive the crazy New England weather for many years to come.

By Briana Colangelo

Bri is a self-taught DIYer who's had a passion for DIY projects since a young age. After buying a 1958 cape home, she has been slowly transforming each room in her house. Bri also shares her designs and DIY projects as a content creator on Instagram and TikTok @d.i.y.bri.

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