How Many Coats of Thompson’s Water Seal? (Explained!)

Thompson water seal has lots of benefits. The transparent seal is waterproof and prevents water damage to wood, brick, and concrete. But how many coats of Thompson water seal are needed?

You need one coat of Thompson water seal. A coat of Thompson water seal contains enough solvents and plasticizers to seal the surface. However, if you want a deeper color of the finish, you can apply a second coat of Thompson water seal.

You should know that the second coat must be applied while the first coat is drying. It’s recommended to apply the second coat within 2 hours after applying the first coat. If the first coat is allowed to dry completely, it will repel the second coat.

This post reveals more about Thompson water seal application including tips to know if you need extra coats of Thompson water seal. Let’s dive in.

Why Does The Number Of Coats Matter For Thompson’s Water Seal?

The number of coats matter for Thompson water seal because the coats determine the water resistance and sealing qualities of the water seal. The number of coats determines how long the Thompson water seal will take to dry, the color of the finish, and the level of penetration. To ensure that the seal dries properly and is waterproof, you need to apply the right number of coats based on the manufacturer’s instructions.

Like all types of paints and sealers, the number of coats matters for Thompson water seal for several reasons. The main reason is that it determines how long it takes for the seal to dry. More coats of Thompson water seal mean that the sealer will take longer to dry than when you apply a few coats.

Also, the number of coats determines the shade of the finish. More coats will give you a deep color shade while a few coats will give a light color shade. Asides from these, the waterproofing and level of penetration also depend on the number of coats that you add.

So, the number of Thompson water seal coats matters a lot. So, how do you know if you need an extra coat of Thompson water seal? Let’s take a closer look at that.

How To Know If You Need An Extra Coat of Thompson’s Water Seal?

The best way to know if you need an extra coat of Thompson water seal is to inspect the first coat as it dries. If you suspect that the first coat will produce a lighter coat than you need when it dries, you should apply a second coat. An extra coat of Thompson water seal will give a deeper finish.

You can also know if you need an extra coat of Thompson by inspecting the surface before applying the Thompson sealer. If the surface is riddled with gaps or is very porous, then you’ll need a second coat as the first coat is absorbed into the surface.

The manufacturer’s guide is another place to look when questioning a second coat of Thompson water sealer. The manufacturer’s guide to applying the seal will indicate if a second coat is needed.

You should know that a second coat (if needed) needs to be applied before the first coat dries. Thompson water seal is a sealant that becomes resistant to paints, sealants, and stains when dry.

So, if you allow the first coat to dry, it will repel the second coat or extra coats that you add making it impossible for the successive coats to stick. It’s recommended to apply a second coat (if needed) within 2 hours after applying the first coat.

Next, let’s check out what happens if you don’t use enough coats of Thompson water seal.

What Happens If You Don’t Use Enough Coats Of Thompson’s water seal?

If you don’t use enough coats of Thompson water seal, the finish will not be as waterproof as it is meant to be. When this happens, moisture from spills, water leaks, and splashes will eventually penetrate the water seal. If left unchecked, this can cause water damage to the surface. Without applying enough coats, you’ll also notice a lighter-than-expected finish when the seal dries.

Thompson water seal is designed with solvents and chemical additives to become waterproof when dry but the finish only becomes waterproof when there is enough of it on the surface. If you apply less than the recommended number of coats, the water seal will not be waterproof.

Instead, the water seal will be water-resistant. What this means is that the Thompson sealer will repel moisture and water for a while but not completely. After a while, moisture will begin to seep underneath the water seal. When this happens, you’ll experience water damage on the surface.

Since more coats mean a deeper finish, then not applying enough coats means a lighter finish. So, if you don’t apply enough coats of Thompson sealer, you’ll end up with a lighter color shade and a weak water seal finish.

Can You Use Too Many Coats Of Thompson Water Seal?

It’s possible to apply too many coats of Thompson water seal and this happens when you apply more than 2 coats of the water seal on a surface. More than 2 coats of Thompson water seal are too much on any type of surface.

When you apply too many coats, the Thompson water seal will not dry and will turn tacky after a few hours. Also, the finish will not be smooth. Instead, it will get gooey and give a milky appearance.

If you apply more than 2 coats of Thompson water seal on brick, concrete, or wood, the water seal will not dry. Instead, it will turn tacky. In this state, the water seal will be very sticky and can trap dirt causing it to get filthy and produce a foul smell.

Asides from the tackiness and foul odor of the water seal, applying too much Thompson water seal will also cause the finish to be milky in appearance. Thompson water seal is meant to give a transparent color when dry but if you apply too many coats, the finish will turn milky or cloudy instead of being transparent.

How Long Should You Wait Between Coats Of Thompson’s Water Seal?

You should wait 2 hours between coats of Thompson water seal. This is because successive coats of Thompson water seal need to be applied before the existing coat is completely dry. Since Thompson water seal takes about 4 hours to dry, you need to apply the next coat within 2 hours after applying the first coat. This way, the next coat will bond well and dry with the first coat. You should know that it’s generally advised to apply thin coats of Thompson water seal.

If you don’t apply the second coat within 2 hours, it will not stick. Thompson water seal has unique sealing properties. When dry, the sealer becomes resistant to any type of moisture including more coats of Thompson water seal.

So, it’s advised to apply the second coat when the first coat is about 60% dry or within 2 hours after applying the first coat. Since the first coat isn’t completely dry, it’s not moisture resistant and will accept another coat. You shouldn’t apply more than 2 coats of Thompson water seal.

How Long Does A Coat Of Thompson’s Water Seal last?

A coat of Thompson water seal can last up to 10 years if properly applied and maintained. This is because there are several solvents, plasticizers, and additives in the water seal.

The presence of these additives in the water seal makes the sealer strong and durable. These additives also make the sealer resistant to a harsh environment. So, if properly applied, the water seal can last a decade.

If you want the Thompson water seal to last longer, you should apply a finish on it but let the water seal dry for at least 30 days before applying a finish over it.

Final Words

In summary, you only need a coat of Thompson water seal for proper waterproofing and sealing. But, if you are using the sealer for its color, you can apply 2 coats for a more colorful finish.

You shouldn’t apply more than 2 coats of Thompson water seal and the second coat should be applied within 2 hours after applying the first coat.

The finish when properly applied can last over 10 years. You should follow the manufacturer’s guide to know how best to apply the water seal.