Learn about the best stains for exterior wood on DIY outdoor wood projects, the best type of wood to use, and details about finishing outdoor wood projects!
After sharing many DIY outdoor projects over the years, one of the most often asked questions I get is: What is the best exterior stain to use on DIY outdoor wood projects and furniture?
I honestly could not answer this question properly because I had only used a few exterior stains and sealants and often wondered if there were other great products worth exploring.
Two years ago I set out to find the answer to what is the best exterior stain. I researched and tested out 6 popular exterior wood stains and sealants on unfinished, pine wood samples.
I left the stain samples outside, uncovered for nearly 2 years.
Before I get into the details and results of this experiment, I want to share some important information to understand about outdoor wood projects, especially DIY outdoor furniture projects.
Note, this post contains some affiliate links. I may earn a commission if you shop those links (at no cost to you). Thank you for supporting my small business. For more info see my disclosures here.
Types of Wood for Outdoor Projects
One of the best types of wood to use for outdoor projects is naturally, weather resistant wood. Example wood species include cedar, redwood, teak, and oak.
I love to use cedar wood when possible because it’s a naturally weather resistant and insect resistant wood. It’s also more commonly available at my local home improvement store and lumber store. And it’s more affordable than woods like oak and teak.
For example, I used cedar on our DIY raised garden bed with legs and DIY vertical planter stand.
However, cedar can still be pricey and not as easy to find compared to other common building woods like pine, whitewood, and framing lumber.
So, if you want to use this inexpensive lumber, then you need to stain or seal it with a good exterior stain/sealant.
Exterior Stains vs Polyurethanes vs Paints
The most common type of exterior finishes for outdoor wood are exterior stain, polyurethane, and paint. There is an incredibly helpful article about these and finishing outdoor projects by Ana White!
But, basically stain penetrates the wood while polyurethanes and paints dry on top of the wood. So, exterior stain is best to use as it won’t crack as much as paint and poly with the expansion and contraction of wood that is more extreme outside.
For this reason, I decided to just test out different exterior stains. However, I had to test out one of the most popular exterior sealants – Helsman Urethane.
Types of Exterior Wood Stains
One last thing to understand about exterior stains is that there are water based and oil based stains, just like with interior wood stain.
They can be applied similarly. Check out my how to stain wood tutorial for more details.
Most of the stains I am testing are water based but I did test out one oil based stain.
Another benefit about exterior stain is that over time if the finish is looking rough you can apply a fresh coat. However, this can vary by the specific exterior stain, so it’s a really important detail to check when buying exterior stain.
For example, some water based stains have to be sanded down for reapplication, but they are longer lasting and more durable than oil based exterior stains.
Whereas most exterior, oil based stains will actually need to be refinished a few years sooner than water based, but you can just reapply a fresh coat over the old coat, no sanding needed, just cleaning!
Stain Transparency and Opacity
Exterior stain is typically available in solid, semi-transparent, and transparent.
Solid shows the least amount of grain, hides imperfections most, and acts more like a paint (but still penetrates the wood). For this reason it’s more durable than more transparent stains.
I actually used solid stain for the first time on our DIY AC fence. Then, I used it again for our DIY hose stands!
Semi-transparent stain shows more wood grain while still providing good protection. It’s one of the most popular stain transparencies, so that is what I tested in my experiment.
Transparent stain shows the most grain with a little bit of color, but is the least protective compared to the others. I have not used this type of stain.
How long do exterior stains last?
Keep in mind no wood project will last outdoors forever. Each finish varies in the time-frame it says it can last.
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But, in general most water based exterior stains say they will last 3-8 years and oil based can last 1-5 years.
Finishes do last longer on vertical surfaces (like a fence) vs. horizontal finishes (like a table top or deck floor).
6 Exterior Wood Stains and Sealants I Tested
| Stain Name & Where to Buy | Type | More Details |
| Valspar one-coat semi-transparent stain sealer | Stain, Water based | How to Apply |
| Behr semi-transparent waterproofing stain sealer | Stain, Water based | How to Apply |
| Thompson’s WaterSeal | Stain, Water based | On Label |
| Helmsman Spar Urethane | Poly, Oil based | How to Apply |
| Ready Seal Semi Transparent Wood Stain Sealer | Stain, Oil based | How to Apply |
| DEFY Extreme Semi-Transparent Wood Stain | Stain, Water based | How to Apply |
Note, I followed the application directions on each stain, as some required only one coat vs two and slightly different drying and curing times. However, I did wait several days before placing them outside, so they would be ready to use!
After applying the stains and sealants to each 2×6 pine wood sample, I left them outside, uncovered for almost two years. Here is what they look liked after staining vs after two years outside:
And here is the wood sample next to the stain/sealant used on it:
Before assessing them fully, we power washed them to see the clearest results:
The Winners
The top two winners in my opinion were the Defy and Valspar. These two stains had the least amount of mildew on them after power washing. Although, I do think the darker color of the stain helps to conceal what mildew didn’t rinse off.
Unfortunately, the Valspar rubbed off in a few areas from the power washer (the white spots). I think the Defy was the most durable overall and faded/cracked the least, but the Valspar formed the least mildew.
The Valspar only required one coat for application, the DEFY needed two coats.
The other advantage about Defy is that it was one of the only water based exterior stains in my research that does not require any prep (besides cleaning) to re-coat the wood when needed. Many others required sanding.
I’ve never used Defy before on a project, but I would like to now for a future outdoor project!
The Runner Ups
Behr and Ready Seal also performed overall well with minimal cracking. However, these did form more mildew than the winners. The lighter color didn’t help them either.
The Least Durable
The least durable were the Thompson’s and Helsman Spar Urethane. These really look weathered and rough. I would not use these…maybe in a covered area would be better results.
My best tip for long lasting outdoor wood furniture
As you can see, the results are quite interesting! No matter what stain you use on your outdoor project, if it’s outdoor furniture, my #1 tip for durability is to cover your outdoor wood furniture when it’s not in use.
I’ve used the Valspar outdoor stain on the majority of my outdoor wood projects, like our popular DIY outdoor couch and it has held up overall well for me.
Although, I have noticed after 5 years on our outdoor couch and chair, the stain color has turned more orange in tone. I wonder if a more brown based color from the line would have been best to use to avoid this!
Anyways, I always keep our outdoor couch and chair covered with these outdoor covers, especially now that they are outside on our uncovered DIY paver patio and not in our covered sunroom anymore.
Have you ever used one of these stains/sealants before? What was your experience? Or is there another outdoor stain/sealant you love using? Share in the comments!
I hope my two year experiment to find the best exterior stain and my tips on finishing outdoor wood projects has been helpful!