I’m a complete novice with no woodworking experience so apologies if this is a dumb question. Would it be possible to use uncut wood to build a pergola like the one in the picture and still treat it for weathering? We live in Tennessee so unlike the eucalyptus pictured it would likely be pine, poplar, or oak from our property. Any and all advice is appreciated. Thank you!

enter image description here

Re: Sorry but I can't comment on your posts individually since I'm a new contributor.

Graphus, ideally I would like it to last at least 10 years. Anything less than that doesn't seem worth cutting so many trees for.

Gianluca, we get 50+ inches of rain per year and since this would be outdoors maybe the poly coating is my best option.

Caleb, I'm okay with bark being removed so long as they still keep their natural contour. With thin pieces I'm not sure how feasible this is. But I'm guessing if I can achieve that then I could get them pressure treated and maybe even double down with a poly coating.

Thank you for all the responses!

2nd Re: Graphus, thank you for taking the time to provide so much info. I absolutely do not want to resand and varnish this every few years, nor do I want a to add a yellow tinge to the wood if it can be avoided. For the oak, do you mean I could leave it completely untreated with bark still on and it would last (i.e. simply cut it down and use as is)? If we go with pine (it's harder to part with our hardwoods and we have plenty of pine we'd like to clear anyway), you mean we should simply remove the bark and then treat it as normal (sans poly)?

For the link to the photo source: https://www.elledecor.com/design-decorate/house-interiors/a34850863/mario-connio-uruguay-house/ Please let me know if I need to provide any more information for the picture.

  • Hi Anna, welcome to StackExchange. Oak is a naturally rot-resistant wood, so if it were possible to confine yourself to that you could get a very long service life without the need to coat the wood or treat it in any way. Now that said, wood in thick section in species that aren't particularly resistant to rot can be quite hardy and can last in decent enough condition (it is decaying, but not actually falling apart) for a considerable time, as long as it's not in direct contact with soil. So do you have an idea of the lifespan you'd like to get from the pergola once built?
    – Graphus
    Jan 23 at 23:57
  • Anna, it's easy to earn enough rep to be able to Comment, you just need to do a few things here and there like upvote useful Answers etc. I would strongly recommend discounting any suggestions involving using varnish here, as you're unlikely to like the look (all exterior varnishes are strongly yellow/orange and give a very noticeable amber colouring to wood) but even more importantly this will require regular upkeep. I doubt you'd want to sand and revarnish your pergola 2 or even 3 times over the next ~10 years!
    – Graphus
    Jan 25 at 16:03
  • Now re. weathering, you could treat this just like you would common fencing, or an unpainted shed, and use exactly the same kind of products. These exterior wood preservatives will still require some upkeep, but it'll be much less onerous (and far cheaper) than with a quality exterior varnish ($$-$$$). But to reiterate what I said initially, if you could confine yourself to oak you wouldn't need to use anything on it and it will endure. So, as long as you're OK with the silvery/grey colour that wood naturally changes to with exposure to the elements you'd be done once the pergola is built.
    – Graphus
    Jan 25 at 16:13
  • Welcome to Woodworking! One of the rules here is that we expect pictures to include the source info. Please let us know what magazine that image is from, preferably with a link to the source. (There are also rules about ensuring the image can be publicly used, but people tend to look the other way a little bit on that one.)
    – FreeMan
    Jan 25 at 17:26
  • @FreeMan, ALL images are actually fair game for use in this sort of way, even if specifically identified as being copyrighted material like in an image archive like Getty images. This is because of fair-use exceptions which allows for copyrighted material to be used in specific ways, one of which is "educational purposes" as the US code words it.
    – Graphus
    Jan 26 at 12:10

Obviously yes. The only thing you must do before treating it is to clear it from eventual dirt, detach the parts that are already almost detached and stabilize breaks, if present, filling them with some UV resistant epoxy eventually mixed with sawdust.

Then you can treat it with whatever finish you like, but you must consider the climate when choosing what to use.
For this I cannot suggest anything, don't know how the climate is in Tennessee, but a local dealer probably can offer some good suggestions about products to use.

If I had to do it, I would use a good quality UV resistant epoxy and then some good transparent polyurethane paint.

If you really want, you can also research some more traditional ways of protecting wood using natural product and method, but some of these are much more laborious than using epoxy and paint. But at the same time, they teach a lot.

  • Care to explain the downvote ?
    – Gianluca
    Jan 24 at 22:42
  • The photo in the question shows eucalyptus branches with bark still on. Are you recommending applying some sort of finish, possibly including epoxy and polyurethane paint, on top of pine, oak, or poplar bark? I'm not sure there's anything obvious about that approach; have you actually done this successfully, or are you just spitballing?
    – Caleb
    Jan 25 at 7:09
  • I've done it, though not to this scale. The logic behind is that in my experience, bark tends to rot faster than the wood and became unstable especially if exposed to weathering. Epoxy just stabilize the bark and protect wood and bark from weather. That said, I always seen the bark removed when building something (even if it does not need to withstand weather) or stabilized in some way if left, even in case it was an indoor only. And that people are far better wood worker with much more experience than me.
    – Gianluca
    Jan 25 at 9:14
  • 1
    OP states right at the start that they're a complete novice with no woodworking experience, so where do they get the fine wood dust necessary to use along with epoxy for the fills you're suggesting? And how do they do those fills (again, complete novice)? Perhaps most important here, any estimate the cost of the two different epoxy products you've suggested above? The cost of these alone might be enough to discount them. And what is "transparent polyurethane paint"??? If you're referring to varnish use that word, so that the OP (and any future reader) aren't immediately set up for confusion.
    – Graphus
    Jan 25 at 16:23
  • @Graphus sawdust it not really hard to get, OP just need to use some 80 grit sandpaper on a piece of wood every time some of it is needed. But if OP need to cut the tree I don't see any problem to get it. The epoxy to do the work I suggest, is between 130/170 euro for 5/8 Kg, depending on the brand. Now, without knowing the size of the pergola, it is difficult to say how much expensive it can be. About the paint, it is not exactly varnish, here we call it "impregnante", it is just the better translation I find
    – Gianluca
    Jan 25 at 17:03

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