I'm gearing up to build a small arched bridge that's around 8 feet long and 4 feet wide to span over a pond. Most of my projects are usually indoors, like furniture, so I'm looking for some advice on wood choices for this outdoor project. I live in the Pacific Northwest and was thinking about using Cedar, specifically Western Red Cedar. Are these good options in terms of durability? Should I finish the wood, or is it better to let it weather naturally? Any other tips or considerations would be really helpful! Thanks!
3 Answers
You're definitely on the right track with your wood selection! Personally, I’d recommend letting the bridge age naturally; it gives it a nice rustic look. Also, placing it on concrete blocks will help prevent rot where it meets the ground, which is a smart move!
Cedar is a solid choice! If you're building at ground level, consider using pressure-treated lumber there. I live in the PNW too, and I've used Cedar for two big outdoor projects on pressure-treated skids, and they've held up incredibly well. Just make sure you have about 6 inches of crushed rock underneath for good drainage—you'll be good to go!
Redwood might be worth a look too! It's stronger and has similar resistance to rot as Western Red Cedar, plus it might end up costing less since tariffs may impact cedar prices. If you go with any cedar, choose heartwood over sapwood for better durability. For structural parts, pressure-treated lumber is an option, but I’m not a huge fan. If you want to finish it, be sure to use something with UV inhibitors to slow down aging, but avoid those glossy varnishes that peel badly.
Great suggestions! We have plenty of Western Red Cedar here, so I hope it’s not too expensive.
Thanks for the advice! I'll definitely consider the concrete blocks.