Why is Kilz Not Recommended for Flooring? (Explained!)

It’s always advised not to use Kilz on flooring but I never understood why. So I decided to carry out some research and here is what I found out:

The reason Kilz is not recommended for flooring is that Kilz doesn’t have the glossy finish that is associated with most floor finishes. That means that Kilz will not protect your floor from high foot traffic and heavy use.

Asides from that, Kilz has a strong smell that takes up to 4 days to disappear. So using Kilz on a large surface like indoor flooring will cause the unpleasant smell to linger in the home for days.

That said, you can only use kilz on floors that are already strong and durable like concrete and tiles as such floors don’t need much protection from the Kilz coating.

Let’s go deeper into this article to find out more about using Kilz on flooring.

What is Kilz?

Kilz is a primer paint that is usually oil-based and as such thick. Kilz is commonly used to seal and trap stains, odors, and imperfections on the surface. Kilz also does a good job of preventing bleed-through, especially on porous surfaces.

The primer coating is usually designed with flat or no sheen which means that kilz dries to form a textured layer. This is the main reason kilz isn’t advised for floors. As a textured coat, the primer coating alone can’t survive the heavy usage and high foot traffic of floors.

Let’s find out what happens when you use kilz on flooring?

What Happens When You Use Kilz On Flooring?

When Kilz is applied over a floor, the kilz coating will adhere properly to the floor. This is because kilz is designed with impressive adhesive qualities. However, you should know that the Kilz coating will not protect the floor as much since Kilz is a primer paint and not a floor finish.

When Kilz is applied on a floor, it will stick to the floor because Kilz is a primer coating meaning that it has good adhesive qualities. However, Kilz is not a glossy coat. This means that when the coat is applied to the floor, it will dry to form a textured surface. Since the surface of the Kilz primer is not glossy, it will not protect the floor as much. It makes the floor prone to dust nibs, dents, and damage from foot traffic and heavy use.

Asides from the poor protection that the Kilz primer will offer when used on a floor, the Kilz primer coating will also hide filth, stains, and imperfections on the surface since that is what the primer is designed to do. So when you apply Kilz on flooring, the Kilz coating will stick properly but it will leave the floor prone to damages and it will hide stains on the floor.

However, you should know that Kilz primer can be used as an undercoat for a floor finish. Since the product hides stains and imperfections, you can use it on the floor before applying a proper floor finish. You should also know that Kilz can be applied on some types of floors. Let’s find out what type of flooring you can apply kilz on.

Types Of Flooring That You Can Use Kilz On

Kilz can be applied on floors that are already strong and durable. This is because such floors can handle high traffic and usage so the floor doesn’t need much protection from the floor. Here are some floors that you can use Kilz on:

  1. Concrete Floors

Concrete floors are super strong and tough. The floor is usually made from a combination of concrete, sand, and other durable materials. As such, concrete floors by design can’t be damaged easily. So using Kilz on a concrete floor wouldn’t be a bad idea.

However, you should know that Kilz will not dry to form a glossy layer on the concrete. Instead, the kilz coating will become textured which means that it can be easily stained. So you will need frequent cleaning.

  1. Tiled Floors

You can also use Kilz on tiled floors. This is because Tiled floors are usually strong and moisture-resistant. So the floor is tough enough to handle the high foot traffic and usage that is associated with indoor floors.

However, you should know that using kilz on tiled floors means that the kilz will not last long. One major reason for this is that the kilz primer is not a floor finish. So it can’t stand the constant use on the floor. Also, the Kilz will not adhere well to the tiled floor since ceramic tiles are usually slick and non-porous.

  1. Subfloors

You can also use Kilz primer on subfloors. This is one type of flooring that Kilz primer is actually designed for. Subfloors are the foundation for floor finishes and using Kilz primer on the subfloor will prep it well. However, you are to apply a final coat over the Kilz if you use it on the subfloor.

  1. Composite Floors and Decks

You can also use Kilz primer on composite decks  

Next, let’s check out the types of floors you shouldn’t use Kilz on.

Types Of Flooring You Can’t Use Kilz On

You shouldn’t use Kilz primer on floors that require a finish coat and floors that are not strong. This is because these floors are ordinarily not strong enough to withstand heavy use and foot traffic. So a strong and glossy finish is usually required on such floors to make them last longer.

Here is a list of floors you shouldn’t use Kilz on:

  1. Wooden Floors

You shouldn’t use Kilz primer as the final coat on wooden floors because Kilz doesn’t protect the wooden surface from moisture and dents which can cause the wood to rot. Also, using Kilz primer on wood will prevent the finish coat, especially wood stains from penetrating and sticking properly to the wood.

  1. Outdoor Floors and Decks

You should never use Kilz on outdoor or exterior floors and decks. This is because these floors are usually exposed to the elements and a high amount of moisture meaning that the floor will be prone to mildew growth without a moisture-resistant coat. Kilz however is not a moisture-resistant coat and as such will allow the floor to rot and develop mildew.

  1. Finished Floors

You shouldn’t use kilz on finished floors unless you want to apply a new finish. This is because when kilz is applied on finished floors, the white coat of Kilz primer will not stick to the floor properly. The existing finish on the floor will prevent proper adhesion between the kilz coating and the floor. Also, using Kilz over a finished floor will cover the existing finish on the floor.

You should know that Kilz can be used on the listed types of floors but only as a preparatory coating. Kilz primer should never be used as a final coat or finishing coat on the said floors because these floors are not strong enough to survive heavy use and foot traffic without a tough top coat.

For the floors listed above, you need a strong and moisture-resistant coat like epoxy flooring or polyurethane but you can use Kilz on the floor before laying the final coat or finish.

So how long should Kilz dry before laying the final coat on the floor? Let’s find out.

How Long Should Kilz Dry Before Laying Floor Finish?

You should let Kilz primer dry for at least an hour before laying the floor finish on it. Kilz primer is known to get dry enough for a floor finish between 30 minutes and 1 hour after the kilz coating was applied. However, 1 hour is usually the safe time to wait before laying the floor finish.

One reason to leave Kilz for at least an hour before laying the floor finish is that Kilz is usually an oil-based primer. As such, the primer coating will be thick and we all know that thick goats take a while to fully dry.

To know if the Kilz coating is dry enough for a floor finish, try sanding the kilz coating with a fine-grit sandpaper. If the sandpaper moves over the kilz primer freely, then it has dried enough. But if the sandpaper gets clogged by the kilz, it’s because it is still wet and not ready for a floor finish.

Here are common questions asked by DIYers like yourself about using kilz on floors:

Does Kilz primer protect floors?

Kilz primer doesn’t protect the floor from factors that can damage it like moisture and dents. This is because kilz is designed to seal surfaces and not protect floors. As a result, kilz doesn’t have a strong top coat to protect floors.

Is Kilz Primer Waterproof?

Kilz is not waterproof. Though the primer stops stains and odor on the surface, the primer coating will crumble and peel off if exposed to high moisture content for several days. This is because the kilz is not waterproof. If you want a water-resistant finish for your floor, it’s best to look towards glossy paints like exterior polyurethane.

Can you leave kilz unpainted?

It’s not a good idea to leave kilz unpainted. As explained earlier, kilz is not strong enough to withstand heavy and consistent use so the primer coating needs a top coat to last long on the surface. If you leave kilz unpainted or without a top coat, the kilz primer will peel off eventually.

Final Words

In summary, using Kilz over flooring is not recommended because Kilz is a primer coating and not a floor finish. As such, the kilz coating will not protect the floor properly from dents, moisture, or damage.

You should never use kilz primer as the final coat over delicate flooring and exterior flooring. If you are to use kilz over a floor, you should only use it before applying a final coat of floor finish.

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