February 9, 2022
To be honest, the word “weatherproofing” is misleading. When we see the word weatherproofing, our minds immediately jump to rain and water damage. While wood can rot from water damage, there are other elements that weatherproofing can work against quickly!
Some of these elements include UV light, heat, frost, and insects. And yes, every single one of those can be solved with weatherproofing! While it’s not a complete cure-all, it’s going to lengthen the lifespan of the wood.
So, weatherproofing is a necessary treatment if you plan to have your wood exposed to the elements. Wood is vulnerable! You’ll always have to deal with warping and rotting as long as you’ve got wooden furniture. It’s great for aesthetics, but it requires a lot of protection.
Table of Contents
- What You May Need:
- Method 1: How to Waterproof Painted Wood and Use Sealants
- Method #2: How to Waterproof Painted Wood with Oils
- What Exactly Are the Challenges Outdoor Wood Furniture Face?
- Why Use Polycrylic and Polyurethane? The Suitable Coatings for Painted Outdoor Wood
What You May Need:
For Weatherproofing the Wood:
- Suitable sealants, varnishes, and coatings
- Polycrylic products
- Polyurethane topcoats
- Cleaning brush
- Wood oils
For Making the Wood Oils:
- Apple cider vinegar
- Walnut, linseed or tung oil
- Clean cloth
- Steel wool
Method 1: How to Waterproof Painted Wood and Use Sealants
In five easy steps, you can protect precious, painted wood from the elements. We’ll show you how below:
Step 1: Clean the Wood With Brush and Detergent
Dedicate some space for your outdoor wood furniture. Get a bucket and pour one gallon of water in it. Now, it’s time to get the ratio right!
Prepare your favorite brand of liquid detergent and mix around a quarter of it into the bucket of water. Mix well!
Now, it’s time to get the cleaning brush. Dip and brush the painted wood surface well! Get every nook and cranny.
Step 2: Rinse the Wood and Leave It Out to Dry
It helps if you live in a sunny area for this step! Start early in the morning for step one so you can rinse the suds off quickly. Use a hose to clean the furniture off!
By the time noon rolls around, you can leave it out to dry. If you live in a cooler, humid place, expect the drying to take a few hours.
Step 3: Coat the Wood Surface with Primer
Choose a wood primer. Before you can apply sealant, primer is a must. It helps prepare the base of the wood surface so everything goes on evenly.
Use a paintbrush, dip into the primer, and layer each coat.
Step 4: Apply the Sealant
You can choose to apply either one of the three: polyurethane, varnish, or sealant. Clean off the paintbrush, dip it into your chosen sealant, and apply it evenly onto the surface.
Step 5: Dry the Surface
Congratulations, you’re all done! Leave the outdoor furniture out for up to two days. It should be all ready and dry by then!
Method #2: How to Waterproof Painted Wood with Oils
Linseed, walnut, and tung oil are the best products to waterproof your wood. As they can help the waterproofing process last for several years, they’re ideal products – and are all readily available.
However, they can vary in price. Linseed and walnut are cheaper, and you can pop into grocery stores, repair shops, and hardware stores to get them! Tung oil is best for small projects, as it comes with a pretty hefty price tag. Using a lot of it will drain your wallet.
In all fairness, you should measure out how much oil you have to use for all wood projects, not just tung oil. You have to look out for how much treatment each furniture will need. Your estimate can lead to how much oil you buy.
Step 1: Make an Oil Mixture
Before anything else, take some turpentine and apple cider vinegar. One part of whatever oil you prefer (linseed, tung, or walnut), one part turpentine, and one-half part vinegar is the perfect mixture for durability. Shake or mix the ingredients well so you can apply them onto the wood later.
This creates a strong, durable finish like no other!
Step 2: Use Sandpaper to Prep the Wood
For the wood surface to be thoroughly waterproofed, you have to prepare it for absorption. Plus, putting oil mixture onto wood as it is will only reveal imperfections. You don’t want to highlight the wood’s flaws!
Get fine-grit sandpaper and scrape the wood well. This will get rid of markings and loose bits. Make your wood seem brand new!
Step 3: Layer the First Coat of Oil Mixture
Now that you’ve sanded the surface, it’s time to layer the first coat. Before anything else, though, take the necessary precautions: make sure you wear gloves!
Pour the mixture onto the wood surface and spread it with a paintbrush. Make sure the surface is evenly coated.
Step 4: Let the First Coat Dry
In case you’ve put on a thick layer, use a clean cloth to remove the excess soil. After, you can leave the oil mixture for the wooden surface to absorb, then leave it to dry.
Expect the drying process to take a day or two. When it’s fully dry, use steel wool on the wood surface.
Step 5: Apply the Final Two Coats
Apply another coat! Once again, you have to pour a small amount and even it out with a paintbrush. Let dry for another day or two, then repeat the process.
After everything dries, you can now sand with steel wool.
Congratulations! You have successfully weatherproofed your furniture.
What Exactly Are the Challenges Outdoor Wood Furniture Face?
So, why do we need waterproofing? We’ve mentioned some challenges briefly in the introduction, but we can get more in-depth. Outdoor furniture also has to survive the following:
Let’s take ourselves back to elementary science: wood is biodegradable. So, with time, it will eventually rot. There are some exemptions, like treated lumber or rot-resistant wood species (cedar, redwood, and teak, if you’re curious). However, there’s a chance that the wood you’ve got right now is on its way to rotting completely.
Structural Vulnerabilities (Like Glue and Finish):
Most wood furniture also comes with interior glues and finishes. There’s nothing wrong with those per se – it’s just that they were made for climate-controlled buildings. So, yes, they were made to last indoors.
If you haven’t caught our gist yet, these types of furniture won’t flourish outdoors. With heat, moisture, and fluctuating temperatures, the glue and finish can degrade. Instead of the usual joint glues and finishes, you have to treat the wood to waterproof glue and finishes.
Then, they’d be able to withstand the humidity and temperature.
You have to make sure you buy outdoor furniture. Indoor furniture’s construction tend to be delicate, leaning on the fine, thin side. While they won’t warp and disintegrate indoors, they will once placed outside. Sunlight, rain, and temperature can affect them badly.
Outdoor furniture, on the other hand, was built to withstand these elements. Sturdy, thick pieces and joints are best. Look for those!
Why Use Polycrylic and Polyurethane? The Suitable Coatings for Painted Outdoor Wood
You may have noticed these materials above in the introduction! They’re the most compatible coatings you can use to seal wood outdoors.
However, not all painted wood need sealants. Some are painted with resilient, waterproof paint. Though it’s not a necessity, sealants can still help in many cases! You can extend your wood’s lifespan for a long time. Let’s define both below:
- Usually clear and acrylic
- Has polyurethane resins
- Works best with latex paint
- Water-based formula
Outdoor elements can’t damage your wood with this sealant. It coats and dries clear, too! You just have to remember the following precautions:
- This product doesn’t bond well with high-sheen, oil-based paints
- While this paint can dry clear, heavy application on dark wood can result in a milky, cloudy appearance
- Repels water
- It prevents scratches and discoloration from happening
- Helps seal exterior paints
It’s time for a little vocabulary lesson: water-resistant is not the same as waterproof! So, polyurethane can repel water, but you might still have some water damage. It’s good for protecting your wood overall.
When using a clear polyurethane sealant, you have to follow some precautions:
- Use water-based polyurethane for latex and acrylic coatings
- Use solvent-based polyurethane for oil-based coatings and paints
If you don’t take these precautions, flaking might occur! You don’t want your hard work to go to waste.
Wood looks great when used for outdoor furniture and projects! Though they’re susceptible to a lot of damage when left outdoors, you only have to invest enough time and attention. They’ll last long that way!
Proper care includes applying sealants and stains. Remember: they aren’t a one-time application. You have to refresh the sealant every so often. It won’t be a hassle, either, as sealants are readily available in home improvement and hardware stores!
We hope you enjoyed this guide to weatherproofing painted wood furniture. Make those projects last for us!
Jason is a 40-year-old woodworker, carpenter and author who have been involved in the woodworking and woodcraft industry with 17 years of experience. He is expertise in technical aspects, woodcraft and furniture building projects.