Can Ohia Timbers be Used for Construction?

[MarkP]

For a real challenge, how about traditional timber framing, mortising out beams and pinning with wood dowels? I assume the stuff is hard to cut too, although I cut some recently with a chainsaw and it cut very nicely. The chain was brand new.

[Hotzcatz]

The building code requires structural framing lumber to be marked by an approved agency although they don't require that for ohia posts since generally it gets approved by a licensed engineer or architect.

Ohia is a very hard brittle wood, I don't think I'd care to use it for joists or other areas requiring tensile strength. It does have very good compaction strength which is why it gets used for posts so frequently.

It makes a nice flooring lumber and is great for fine furniture. Wasn't it also used as railroad ties when we had a rail system?

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"I like yard sales," he said. "All true survivalists like yard sales."
Kurt Wilson

[MarkP]

A bunch got shipped to the mainland for railroad ties. Supposedly the tie that got the golden spike driven into it when the railroad linked up in the middle of the continent was Ohia.

[EightFingers]

Nope, not ohia, it was California Laurel. If it was my choice, I would have used koa

[gtill]

There is an engineered process, active in Puna that bores out 3" holes down the center of the ohia (or whatever) post,and filled with a thick walled steel pipe which equate steel in strength, and pass any code requirment.

[MarkP]

It is hard to believe that Ohia is that bad a material. How has it earned such a nasty reputation that it can't be trusted to hold up a porch without being cored for a steel pipe? Does it rot at a remarkable rate?

[Kapohocat]

IMHE, Ohia can be used - the caveat being that the size lumber being replaced such as a 4x4 post must fit "inside" the circumference of the ohia log.
If your log has any warp or wain, it still must encompass the 4x4 as a straight line. (so those cool twisted ones can only be decorative not structural.)

[Hotzcatz]

They can be used for posts, but not legally for framing timber unless you can get them graded and stamped by some sort of lumber stamping agency.

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"I like yard sales," he said. "All true survivalists like yard sales."
Kurt Wilson

[Kapohocat]

The question the plan checker asked was what the F strength was for a project where tropical hardwood 2x6 was being used as subfloor over 16" OC floor joists - and although I researched as far as I could - there was no F Strength listing for many tropical hardwoods or bamboo either.

(F strength refers to the tinsile properties (sp?) of the wood as I understood which measure the amount of deflection when a load is placed on it.)

[peteadams]

quote:

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It makes a nice flooring lumber and is great for fine furniture. Wasn't it also used as railroad ties when we had a rail system?

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According to Hiroo Sato's Pahoa history, the Pahoa lumber mill circa 1907 supplied ties for the Santa Fe Railroad as well as plantation railroads. Supposedly crews didn't like the ohia ties because they were too hard to drive spikes into. He also mentions that many of the trees felled were five feet in diameter and over 100 feet tall.