This post was updated on May 9, 2022
Thompson’s WaterSeal Waterproofer Plus Clear Wood Protector is designed for all exterior wood and decking surfaces. It’s supposed to provide water repellency, prevent water damage, maintain natural wood grain, and resist mold growth. But this Thompson’s WaterSeal product has clearly not been a consumer favorite with professional deck restorers, largely because it doesn’t offer any UV protection and grays in just a few months.
If you have any experience with this product, we’d love it if you shared your Thompson’s WaterSeal reviews and photos in the comment area below.
Thompson’s WaterSeal Clear Waterproofer Ratings (Out of 10)
Appearance After Initial Stain Application: 8
This Thompson’s WaterSeal clear waterproofer did not alter the appearance of the wood. After it was fully dry, we tested its ability to repel water, and water did bead on top of the finish and did not absorb into the wood.
Preventing UV Graying at 2-Year Mark: 1
As far as we can tell, this Thompson’s WaterSeal product does not prevent UV graying at all. This is a huge disappointment, as preventing UV graying is the number one reason to stain your exterior wood and decking.
Wear/Tear and Peeling: 8
The Thompson’s WaterSeal clear waterproofer penetrates deep into the wood. There was no peeling or wearing. We would have given it a 10 if the product still repelled water, but at the 2-year mark, it did not.
Cost per Square Foot: 9
Thompson’s WaterSeal Waterproofer Plus Clear Wood Protector is a very inexpensive product, and its coverage is exceptional. Unfortunately, the saying “you get what you pay for” applies here, as this Thompson’s WaterSeal product offers no UV protection whatsoever.
Preventing Mold/Mildew/Algae: 2
After 2 years, the entire deck was covered in black mold. It seems that the oils used in Thompson’s WaterSeal Waterproofer Plus Clear Wood Protector feed and promote the growth of mold spores.
Ease of Application: 8
Since this is a clear product, it applies extremely easily without the need to back wipe. Just apply it with a pump sprayer or stain pad. This finish does not show overlap marks.
Color Shifting (Darkening) After 2 Years: 7
This product darkens in color because there was a good amount of mold growing in the finish.
Difficulty of Reapplication: 6
A heavy cleaning would be needed to remove all of the graying and mold from the surface.
Overall Score: 6.125
Overall, Thompson’s WaterSeal Waterproofer Plus Clear Wood Protector is a clear disappointment. Any finish that offers zero ability to prevent UV graying should not be considered for your deck or exterior wood.
Photos of Thompson’s WaterSeal Clear Waterproofer’s Effects
- Cost: $34.99 per gallon
- Stain Type: Clear water repellent
- Available Colors: Clear
- Application Temperature: 45-95 degrees F
- Coats Required: 1
- Coverage per Gallon: 200-300 square feet
- Application Tools: Sprayer, pad, brush, roller
- Dry Time: 48 hours
- Cleanup: Mineral spirits
- VOC Compliance: 250 compliant in all states
- More Info: Product Data
- Manufacturer: Thompson’s
About Our Test Deck
- Deck Wood Type: Teak
- Deck Square Footage: 400 square feet
- UV Exposure: Full sun
- How Many Years Tested: 2 years
- Stain Color Used: Clear
All products tested and results are from our experience. We offer no guarantee of similar results. Take into consideration that results may differ due to different wood types, exposure to UV radiation, and natural weathering.
Thompson’s WaterSeal Clear Waterproofer FAQs
Is Thompson’s WaterSeal Any Good?
Our experience with Thompson’s WaterSeal Waterproofer Plus Clear Wood Protector was disappointing overall, and we would not recommend this product. Its inability to prevent UV graying is too harmful to your deck’s wood.
What’s Better Than Thompson’s WaterSeal Waterproofer?
How Long Does Thompson’s WaterSeal Last?
Thompson’s WaterSeal Waterproofer Plus Clear Wood Protector claims to last for up to 4 years when applied correctly. In our experience, it held up well but no longer repelled water after 6-12 months.
Is Thompson’s WaterSeal Waterproof?
Thompson’s WaterSeal Waterproofer Plus Clear Wood Protector is made to waterproof exterior wood.
Can You Use Too Much Thompson’s WaterSeal?
Yes: Applying too much Thompson’s WaterSeal clear waterproofer will significantly increase the amount of time it takes to dry, and it may not dry properly at all.
Does Thompson WaterSeal Protect Wood?
Thompson’s WaterSeal Waterproofer Plus Clear Wood Protector is intended to protect wood, as the name would indicate, but our testing produced dismal results. It does a very poor job of preventing black mold and UV graying, two things that are very harmful to the wood.
Is Thompson’s WaterSeal Water- or Oil-Based?
Thompson’s WaterSeal Waterproofer Plus Clear Wood Protector is an oil-based product.
How Do You Use Thompson’s WaterSeal Waterproofer Plus Clear Wood Protector?
This product is easy to apply with either a stain pad or a pump sprayer.
Does Thompson’s WaterSeal Contain Silicone?
No, this Thompson’s WaterSeal product does not contain silicone.
Does Thompson’s WaterSeal Come in Different Colors?
This particular product is clear, but they also make Thompson’s WaterSeal Waterproofer products that include Thompson’s stain in different colors.
How Many Coats of Thompson’s WaterSeal Do I Need?
In most cases, you will only require one coat.
Can Thompson’s WaterSeal Be Used on Stained Wood?
No, Thompson’s WaterSeal Waterproofer Plus Clear Wood Protector cannot be applied over stained wood, regardless of whether the stain was oil- or water-based.
Does Thompson’s WaterSeal Darken Wood?
Our review of Thompson’s WaterSeal Waterproofer Plus Clear Wood Protector found that it did darken wood over time due to the large amount of black mold that grew in the finish.
How Long Does Thompson’s WaterSeal Take to Dry?
The Thompson’s WaterSeal dry time is approximately 4-24 hours before it is considered safe to walk on.
At What Temperature Can You Apply Thompson’s WaterSeal?
The application temperature for Thompson’s WaterSeal products is between 45°F and 95°F.