Beautifying and Protecting Wood in High Moisture Areas: A Comprehensive Guide

High moisture conditions pose a significant challenge for wood and wood finishes. Whether it’s a horse barn, bathroom, kitchen, or an outdoor deck exposed to the elements, the moisture can cause warping, rot, and mold growth. The right finish not only enhances the natural beauty of the wood but also forms a barrier against moisture ingress.

The importance of selecting the right finish cannot be overstated. It’s about:

  • Maintaining the natural aesthetics
  • Ensuring longevity 
  • Reducing maintenance costs
  • Minimizing reapplication disruptions with long-lasting coatings

This guide aims to unravel the complexities surrounding wood finishes in high moisture environments, aiding you in making informed decisions to protect your wood effectively.

Through an exploration of how moisture interacts with wood, a dive into various types of wood finishes, and a comparative analysis, we’ll arm you with the knowledge you need. In addition, a FAQ section will address common concerns and provide professional tips for navigating the world of wood finishes in moisture-rich settings.

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Understanding Moisture and Wood Interaction:

The relationship between wood and moisture is a nuanced one, governed by the natural properties of wood and the surrounding environment. Here’s how moisture affects wood:

  • Absorption and Expansion: Wood is hygroscopic, meaning it absorbs moisture from its surroundings. When wood absorbs moisture, it expands. This is particularly noticeable in high humidity or damp conditions.

  • Contraction: Conversely, when wood loses moisture, it contracts. This often occurs in dry conditions or during the colder months when indoor heating is used.

  • Warping/Cupping: The uneven absorption or loss of moisture can lead to warping. This is because different parts of the wood may absorb or lose moisture at varying rates, causing some areas to expand or contract more than others.

  • Rot and Mold: Excess moisture can lead to rot, which weakens the wood, and mold growth, which is not only unsightly but also a health hazard.

  • Discoloration: Moisture can cause discoloration, either from the water itself or from mold and mildew growth.

Choosing the right finish for wood in high moisture areas is crucial to mitigate these issues. A proper finish creates a barrier that reduces the amount of moisture the wood can absorb or lose, thereby providing protection against warping, rot, and mold.

In the following section, we will explore various types of wood finishes to help you make an informed decision on the best protection for your wood in high moisture conditions, but based on your unique and specific requirements of your project.

Types of Wood Finishes


Varnish is a popular choice for wood finishing, especially in areas prone to high moisture. Here’s a breakdown of its characteristics and why it might be the choice for you:

  • Composition: Varnish is made from resins, solvents, and drying oils. Its formulation creates a hard, transparent, and protective finish.

  • Moisture Resistance: Being a high-resin content finish, varnish forms a robust barrier against moisture, making it an excellent choice for high-humidity or damp environments.

  • Durability: Varnish is known for its durability and can withstand wear and tear, making it a long-lasting option.

  • Appearance: It enhances the natural look of the wood by adding a warm tone and can come in various sheens from matte to high gloss.

  • Application: It can be brushed on, wiped on, or sprayed, with each technique offering different levels of ease and finish quality.

  • Curing Time: Varnish requires a longer curing time compared to other finishes, which means the wood piece will be out of use for a more extended period post-application.

  • Maintenance: Common varnishes may require occasional sanding and re-coating to maintain its appearance and protective qualities, especially in extremely damp conditions or after a few years of wear and tear.

  • Examples: Spar Varnish, Urethane Varnish, 

Varnish stands as a solid choice for wood finishes in moisture-prone areas due to its protective qualities and aesthetic appeal. However, the longer curing time and potential need for maintenance are factors to consider when choosing varnish as your wood finish.


Lacquer is another favorable option for wood finishes, appreciated for its quick drying time and smooth finish. Here’s what you need to know:

  • Composition: Lacquer consists of resin and a solvent. It’s a clear or colored wood finish that dries by solvent evaporation and can cure upon reacting with oxygen in the air.

  • Moisture Resistance: While not as robust as varnish when it comes to moisture resistance, lacquer provides a decent barrier against moisture. However, it may not be the best choice for extremely damp environments.

  • Durability: Lacquer provides a hard and durable finish, resistant to impacts and scratches, making it a good option for furniture and cabinetry.

  • Appearance: It imparts a rich, glossy finish that can enhance the wood’s color and grain, though matte and satin varieties are also available.

  • Application: Lacquer can be sprayed on, which is quicker and tends to result in a smoother finish compared to brushing or wiping.

  • Drying Time: One of lacquer’s standout features is its fast drying time, often drying to the touch within minutes, though it may take longer to fully cure.

  • Maintenance: Lacquer finishes are relatively easy to maintain. They can be buffed to restore their shine, and minor damage can often be repaired without removing the old finish.

  • Examples: Polycrylic Lacquer, Polyurethane Lacquer

Lacquer could be your go-to if you’re looking for a durable, easy-to-apply finish with minimal downtime. However, if your primary concern is moisture resistance in extremely damp conditions, varnish or other finishes may be more suitable. The choice between lacquer and other finishes will hinge on the balance between moisture resistance, application convenience, and the desired aesthetic outcome.


Shellac is a traditional wood finish that has been used for centuries. It’s known for its easy application and beautiful, classic look. Here’s a deeper dive:

  • Composition: Shellac is a natural resin secreted by the female lac bug, dissolved in alcohol to create a usable finish. It’s an organic compound that’s non-toxic and even used in the food industry.

  • Moisture Resistance: Shellac provides a moderate barrier against moisture. However, it’s not the most robust choice for high moisture areas, as prolonged exposure to water can cause it to white or become cloudy.

  • Durability: While not remotely as durable as varnish or lacquer, shellac provides a decent level of protection against minor scratches and dings.

  • Appearance: Shellac imparts a warm, amber tone to wood, enhancing its natural grain and color. It’s available in different shades and can create a high-gloss, reflective finish.

  • Application: It’s one of the easiest finishes to apply and can be brushed on or sprayed. It dries quickly, allowing for multiple coats in a single day.

  • Drying Time: Shellac dries to the touch in as little as 15 to 30 minutes, making it a fast-drying option.

  • Maintenance: Shellac finishes are relatively easy to repair as new coats can meld with existing ones, but they may require more frequent maintenance compared to varnish or lacquer.

Shellac is a good choice if you’re looking for an easy-to-apply, fast-drying, and non-toxic finish. Its aesthetic appeal is notable, especially for antique restorations or projects where a classic look is desired. However, its lower moisture resistance makes it less suitable for areas with high humidity or direct water exposure.

Oil-Based Finishes

Oil-based finishes are revered for their ease of application and the rich, natural look they impart to wood. Here’s a breakdown:

  • Composition: These finishes are formulated with oil, typically linseed or tung oil, which penetrates the wood to provide protection. They may also contain varnishes and solvents to enhance durability.

  • Moisture Resistance: Oil-based finishes provide a reasonable level of moisture resistance by penetrating into the wood and hardening. However, they may not form as robust a barrier as varnish.

  • Durability: They offer moderate durability, providing protection against scratches and everyday wear and tear, but may not hold up as well to heavy abuse.

  • Appearance: Oil finishes enhance the natural beauty of the wood, deepening its color and highlighting the grain. They usually result in a soft, matte, or satin finish rather than a glossy one.

  • Application: Application is straightforward, typically involving wiping or brushing the oil onto the wood, allowing it to penetrate, and wiping off any excess.

  • Drying Time: Oil-based finishes take longer to dry compared to other finishes, often requiring 24-48 hours between coats.

  • Maintenance: Maintenance is fairly simple, with reapplication of the finish being straightforward. The finish can be easily rejuvenated with a fresh coat as needed.

  • Examples: Teak Oil, Linseed Oil, Tung Oil, Mineral Oil

Oil-based finishes are a solid choice for projects where a natural, warm appearance is desired, and where extreme moisture resistance is not a priority. They are particularly well-suited for furniture, woodworking projects, and indoor applications where the moisture level is moderate.

Water-Based Polyurethane Wood Finishes

Water-based finishes are a modern choice offering quick drying times and easy cleanup. They’ve become popular for both professional and DIY projects due to their eco-friendliness and lower VOC emissions. Here’s a breakdown:

  • Composition: Water-based finishes are formulated with water as the solvent instead of oil or other organic solvents. They often contain acrylic or polyurethane resins for durability.

  • Moisture Resistance: They provide a good barrier against moisture, making them suitable for high moisture areas. The finish creates a surface film that protects the wood from water and other external factors.

  • Durability: These finishes are durable and resistant to everyday wear and tear. They don’t yellow or darken over time, maintaining the wood’s original color and appearance.

  • Appearance: Water-based finishes dry clear, retaining the natural color of the wood. They are available in various sheens from matte to gloss, allowing for a range of aesthetic options.

  • Application: Easy to apply with a brush, roller, or sprayer, and clean up is straightforward with soap and water. They also have lower odor compared to oil-based finishes, which is beneficial for indoor applications.

  • Drying Time: One of the fastest drying finishes, often drying to the touch within 30 minutes to an hour, and ready for a second coat in just 2 to 4 hours.

  • Maintenance: Maintenance is straightforward. They can be cleaned easily with soap and water, and re-coating or touch-ups are simple with no need for sanding between coats unless there are surface imperfections.

  • Examples:  Zar Water-based Urethane 

Water-based finishes are a solid choice for those looking for an eco-friendly, low odor, and quick drying option. They are particularly well-suited for indoor furniture, cabinetry, and flooring, providing a durable and attractive finish with easy maintenance.

Tung Oil Base Wood Finish

Tung Oil Based finishes are an old world proven best choice for almost all of our clients wood beautification, enhancement, water proofing, weather proofing, and finishing. Tung oil based finishes are a proven best solution for most wood finishing.  Here’s a breakdown:

  • Composition: Waterlox Tung Oil Based Sealer and Finish is formulated with Tung Oil  (naturally derived) and Resin (for hardness) floated in the appropriate solvent. Waterlox contains almost 80% tung oil in the resin blend yielding  the highest tung oil content of any “tung oil” finish. Minwax ” tung oil” finish is around 20% tung oil, and the rest is some sort of paint thinner derived from petroleum.  We reccomend our clients stay clear of Minwax products, and encourage them to ponder Zar or Old Masters for a much richer stain compared to Minwax, or Sherwin Williams Oil Stain. 

  • Moisture Resistance: Tung Oil creates an amazing permanent barrier agains moiture intrusion into any wood, creating a permanent barrier against moisture, making Tung Oil Finish most appropriate for for high moisture areas. The finish creates no surface film that can peel or obstruct the natural beauty of any wood. 

    Tung Oil finishes are durable and represent the best finish for wood. Waterlox Finishes don’t yellow or darken over time, maintaining the wood’s original color and appearance. Most all other oil finishes yellow over time. 

  • Appearance: Tung Oil Finishes enhance the natural color of any wood. Waterlox is available in various sheens from matte to gloss, allowing for a range of aesthetic options.

  • Application: Easy to apply with a brush, roller, lambswool pad, or sprayer, and clean up is straightforward with natural mineral spirits, or Citrus Solvent.  

  • Drying Time: One percieved disadvantage of Waterlox Tung Oil Finish is that it cures with exposure to oxygen, meaning a longer cure time of 24 hours is required. The oxygen cured oil is more eco-friendly compared to the fast drying finishes containing xylene and tolulene, both dangerous solvents.

  • Maintenance: Maintenance is straightforward. Tung Oil finishes can be cleaned easily with soap and water, and re-coating or touch-ups are simple with no need for sanding between coats unless there are surface imperfections.

  • Examples: Waterlox Sealer, Waterlox Finish, Waterlox Tung Oil Based Urethane, H20LOX, Waterlox Pure Tung Oil, TruTone Color Infused Buff-in Tung Oil Stain. 

Waterlox H20LOX Tung Oil Finishes are a solid choice for those looking for an eco-friendly, low odor, yet elegant oil finish option. They are particularly well-suited for wood furniture, cabinetry, trim, and doors, and especially real wood flooring providing a durable and elegant finish.

Waterlox Original Sealer Finish TB5284 (mineral spirit based) represents PaintSource first choice for first coat on most wood finishing projects. 

Connect with PaintSource for a quick chat with one of our wood care experts who can guide you to the best wood finish for your individual and unique project. Give us a call at 859-225-0981.

Leave us a voice message, or click here describing your project, and we will help you formulate a solution. 

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Our Product Recommendations

Garden Sheds and Greenhouses

For a fine, elegant finish:

Structures Nature Color and Structures Nature One

For a more rustic look

OneTime Wood Protector or ReadySeal

Waterlox Original Sealer Finish
Waterlox Marine Sealer

Spas/Saunas and Pool Areas

Structures NatureColor or Structures NatureOne

Outdoor Decks and Patios

Decks are complex projects with unique requirements, making a one-size-fits-all product recommendation impractical. Factors like product drying time, sun exposure, lap marks, and the necessity to coat all sides pose challenges. Our Deck Consultation service guides you in selecting and applying the right wood coating from the outset, potentially saving you thousands over your home’s lifetime.

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