Black Walnut for Outdoor Use

[Nathan Jordan]

Has anybody ever used black walnut outdoors, if so how does it hold up compared to something like cedar or cypress? Thinking about making a small table surface for an outdoor cooker and I've already got black walnut on hand, but I've never seen black walnut outdoors.

[John K Jordan]

Has anybody ever used black walnut outdoors, if so how does it hold up compared to something like cedar or cypress? Thinking about making a small table surface for an outdoor cooker and I've already got black walnut on hand, but I've never seen black walnut outdoors.

I haven't used much outdoors but there are various durability assessments online, for example this one which puts black walnut in the 10-15 year moderate durability catagory:
https://www.core77.com/posts/28165/Material-Matters-A-Handy-Wood-Durability-Chart

Other sources, such as the Wood Database, put it at "very durable", 25+ years, resistance to rot but not to insect attack.. I know it was often used as fence posts and outdoors in earlier times because of it's rot resistance.

One thing most everyone agrees on is the sapwood on most species is not durable compared to the heartwood. Note that the sapwood of black walnut lumber is sometimes treated with steam to darken it to match the heartwood. https://www.woodworkingnetwork.com/wood/wood-month/black-walnut-why-coloration-matters I have no idea if the sapwood of walnut is inherently more durable than the sapwood of other species. If not, the darkened sapwood might not be as durable. Perhaps someone has experience with this.

It is recommended in general to apply some wood protection such as a borate treatment followed by an oil sealer. I like to use "boiled" linseed oil on wood exposed to the weather around my farm.

JKJ

[John TenEyck]

I replaced a couple of the boards on my redwood fence that got broken with black walnut just to see how well they would fare. That was around 20 years ago and they are still there, faded gray just like the redwood, but still solid. My take is that black walnut heartwood is pretty darned durable.

John

[Michael A. Tyree]

I've seen walnut used in hay wagon beds that was old and in good shape. Given I have better choices I'd never go that direction. Whit oak would be my 1st choice. Cedar heartwood maybe, depends on tables design. Deep south, cypress heartwood is nearly indestructible weather wise. We camped on a big island in Okefenokee Swamp back in early 1970's and an old hunting lodge there built in 1930's was like new outside covered with cypress shingles, walls and roof.

[Nathan Jordan]

I am here in the south and cypress was suggested to me first, I know its around I just don't have any on hand. The black walnut I have came from a tree that was already lying on the ground when the current land owners bought the property 10 years ago, the sapwood is mostly gone but the heartwood is solid.
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[Mel Fulks]

Thomas Jefferson had his window sashes made of walnut . It's durability used to be much better known when it was
cheaper.

[Mike Cutler]

Has anybody ever used black walnut outdoors, if so how does it hold up compared to something like cedar or cypress? Thinking about making a small table surface for an outdoor cooker and I've already got black walnut on hand, but I've never seen black walnut outdoors.

With some basic finishing, care, and maintenance, it will outlast the cooker by decades.