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How to Seal Painted Wood for Outdoor Use



V Susan
Hi! I'm Susan. I am passionate about woodworking, general DIY and home improvement. If you'd like to connect with me or talk about something you like at mellowpine, drop me a mail at susan@mellowpine.com


Applying Sealer on Exterior Painted Wood

The aesthetic appeal of painted wood makes it a favorable choice for outdoor projects.

In addition to enhancing the overall look of your project, it offers a certain level of protection against various environmental factors.

However, when exposed to harsh elements, it becomes necessary to seal the painted wood to ensure its long-term durability and appearance.

To seal an exterior painted wood, clean and sand the surface for an even surface. Next, apply the chosen sealer using a brush and let it dry. Afterward, lightly sand the surface before reapplying multiple coats per the manufacturer’s instructions and allow it to dry completely.

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Sealing Painted Wood for Outdoor Use: A Step-by-Step Guide

You will need the following tools/materials for sealing painted wood:

Here’s how you can seal painted wood to enhance the longevity of your wood:

Step 1:Prepare the Surface

Cleaning the Painted Wood with Mild Detergent Solution
Cleaning the Painted Wood with Mild Detergent Solution

Proper surface preparation is vital before applying any sealer.

Firstly put on gloves, goggles, and a face mask.

Then, dip a clean cloth or sponge in a mild detergent solution and squeeze it out so no water comes out.

This step is essential as a wet cloth can ruin the finish of your wood.

Step 2:Sanding the Surface

Sanding the Painted Wood with 220 -Grit Sandpaper
Sanding the Painted Wood with 220 -Grit Sandpaper

Lightly sand the surface with 220-grit sandpaper if there are any rough patches or flaws to produce a smooth and even surface for the sealer.

This process necessitates another round of cleaning.

Step 3: Choose the Right Sealer

Oil-Based Polyurethane Sealer
Oil-Based Polyurethane Sealer

The next step is to choose a suitable sealer for the painted wood.

Consider factors such as the type of paint used, desired finish, and the degree of protection needed.

Here, I have used oil-based polyurethane sealer, one of the most commonly available sealers, which produces a stronger barrier for painted wood.

Step 4: Apply the Sealer

Applying Oil-Based Polyurethane on Painted Wood
Applying Oil-Based Polyurethane on Painted Wood

Follow the manufacturer’s instructions for applying the first coat of sealer with a brush or roller.

Divide your work into small sections, commencing from one end and gradually moving towards the other.

Throughout the process, be mindful of any excess drips or air bubbles and smooth them out using the edge of the brush.

Then, allow the sealer to dry completely.

Step 5: Sand and Reapply

Once the first coat dries, lightly sand the surface using 220-grit sandpaper and then with 320-grit sandpaper for a more refined finish and improved adhesion for subsequent coats.

Sanding the Painted Wood with 320 -Grit Sandpaper
Sanding the Painted Wood with 320 -Grit Sandpaper

After sanding the surface, use a clean cloth to wipe the surface to get rid of any dust.

Then, apply a second coat of sealer following the same procedure as before.

Reapplying Oil-Based Polyurethane on Painted Wood Surfaces
Reapplying Oil-Based Polyurethane on Painted Wood Surfaces

Repeat the process if the manufacturer recommends additional coats.

Step 6:Allow the Wood to Dry

After applying the final coat of sealer, allow the wood to dry completely to create a solid and long-lasting protective barrier.

Generally, the manufacturer’s instructions will have the recommended drying time.

Step 7:Regular Maintenance

To ensure the longevity of the sealer, it is crucial to maintain it regularly.

Inspect the surfaces annually and reapply the sealer if necessary.

Benefits of Using Sealers for Exterior Painted Wood

Outdoor wood surfaces that experience high levels of foot traffic or continuous use benefit from a sealer, which keeps the paint intact and safeguards the underlying wood from damage.

Additionally, sealing painted wood serves as an additional layer of protection against moisture and minimizes the risk of cracking, rotting, and warping.

It can also help to protect the wood from the harmful effects of UV rays, which cause the paint to fade and deteriorate.

Moreover, sealing painted wood protects against stains, general wear and tear, or any other physical impact, reducing the need for frequent maintenance or replacement.

Sealed wood surfaces are also less susceptible to the growth of mold, mildew, and fungi, which cause discoloration and structural damage.

Furthermore, they create a non-porous surface that repels dirt and makes cleaning easier.

A sealer can also help to enhance the natural beauty of the wood, giving it a polished and finished appearance.

However, coating your wood with exterior grade paint, such as Benjamin Moore Regal Select Exterior Paint, eliminates the need for applying a sealer over the paint.

Multiple coats of exterior-grade paint are enough to provide necessary protection against outdoor conditions.

Types of Sealers for Exterior Painted Wood

Several types of sealers are available for sealing painted wood for outdoor use.

It is vital to select the best type based on the particular project’s needs.

Here are some of the common types of sealers:

Types of SealersDescription
Polyurethane SealerAvailable in water-based and oil-based formulations
Polycrylic SealerWater-based acrylic products used for flat latex paints
Epoxy SealerProduce a glossy finish,but are expensive
Paint and Sealer Combination ProductsProtect the wood without the need for additional coats
Types of Sealers for Exterior Painted Wood Surfaces

Polyurethane Sealer

Polyurethane sealers, available in water and oil or solvent-based compositions, are widely used to seal painted wood.

Water-based polyurethanes are more environmentally friendly as they contain low amounts of VOC and can quickly dry within hours.

But they are more expensive than oil-based sealers.

On the other hand, oil-based polyurethane sealers are more durable but take 24 hours to dry, require mineral spirits to clean up, and tend to have a more pungent smell.

They cost about $30 to $50 per gallon, compared to the $50 to $100 per gallon of water-based polyurethane.

Polycrylic Sealer

Polycrylic Sealer
Polycrylic Sealer

Polycrylic sealers are water-based acrylic products commonly used for flat latex paints.

They are light-duty sealers that offer a less harmful substitute to polyurethane.

However, it has a flowy and thin consistency, making them difficult to apply on vertical surfaces.

Additionally, they have a cloudy appearance when applied over dark wood or paint.

But they are more affordable than polyurethane and cost around $20 to$30 per quart.

Epoxy Sealers

Epoxy sealers are another durable choice for sealing painted wood that produces a glossy finish.

They are available in clear or colored forms but are expensive and costs between $50 to $200 or more.

Paint and Sealer Combination Products

Recently developed paint and sealer combination products offer a more convenient solution for protecting the wood without the need for additional coats.

Their diverse formulations and colors make it easy to achieve your desired aesthetic while ensuring durable and long-lasting protection.

Frequently Asked Questions(FAQ)

What is the Difference Between a Stain and a Sealer?

Stains contain pigments to enhance the aesthetic appearance of wood.

On the other hand, sealers act as protective barriers against UV damage, moisture, and other forms of deterioration.

However, occasionally wood coloring pigments may be present in sealers.

Which Type of Wood has the Longest lifespan When Used Outdoors?

Teak, one of the best woods for outdoor applications, exhibits the longest lifespan and is resistant to moisture and insects.

It owes its exceptional qualities due to the presence of natural oils and high silica content.

White oak is also more durable than other oak species making it suitable for outdoor applications.

How to Dry Wood Without Cracking It?

Several methods to dry wood include applying linseed oil, varnishes, and paintable wax.

Using salt is also an easy way to dry the wood without toxic chemicals.

Additionally, cutting the wood into manageable sizes and ensuring no knots or defects can prevent cracking.

V Susan
Hi! I'm Susan. I am passionate about woodworking, general DIY and home improvement. If you'd like to connect with me or talk about something you like at mellowpine, drop me a mail at susan@mellowpine.com