If sustainability is your main concern (after cost) go with the Cedar. It can be left to gray naturally. Most unfinished outdoor wood around here is WRC. There are many grades of lumber. If you look around you can find WRC that is close to clear straight grain, but not quite up to grade. This would be a good choice for a low-maintenance naturally-weathered deck. You'll pay a premium over the WRC you are being quoted, but it will still be considerably cheaper than real Mahogany.

Thats true cvg WRC would be a good choice.

Aidan how much do you pay,or think you would pay, for cvg wrc??? Real Mahogany,with the given there are many so called mahogany, can not be that high In my mind clear wrc is going to be about the same as clear all heart Redwood cost $4.60 a bd ft do you think " mahogany " is going to be higher than that ??

Anyway if it is South American is a lot lower than that.

JonMon

Yes, S. American would be the economical way to go. I think the OP is concerned with the Rain Forest and sustainable harvest practices. That will demand a premium.

Last time I bought CVG WRC, it was over $5 per bf. It was left unfinished for park benches. I think Real Mahogany is still quite a bit more $, and hard to find. Even the African Mahog is about $5 per bf for S3S material. I was thinking that in the $3.xx range, one could find A or B grade clear, which is nearly the same quality as CVG, the grains are just as tight, but not perfect quarter-sawn vertical grain lumber. It would be great for an unfinished deck.

I gotcha. Must have missed that part.

Thanks ! John

Hello, I wrote a post last night, then apparently failed to "submit" it. Thank you for your thoughts, and we will see what changing the wood selection to western red cedar does to the cost of the job.

John et al, about a year ago I posted a query about a Norwegian material called Kebony -- soft woods treated with furfuryl alcohol (sugar cane processing byproduct) in a kiln so that it becomes a nontoxic resin, making the wood hard and rot-resistant. Has anyone seen this material in the interim? They have a representative in Virginia, apparently, but there don't seem to be many projects in the US yet. Norwegian projects look interesting. Hope this process holds up well under scrutiny and time, because it would be a nice alternative. We're requesting a sample of southern yellow pine treated with the Kebony process -- their weathered Kebony maple is beautiful, but also quite expensive.

Not real sure about the furfuryl treatment but thermally modified lumber has been around for a long time,They even work on partical board if you can belive it.

Over here in Cow Town Oklahoma a local sells TM yellow pine. We are talking 50 / 60 hrs heat and steam production the material turns brown with increased britllenss. This product comes with a coat of finish on all four sides as well.
In my test even though it might have long life with no bugs or rot going on,nothing left for them to feed on , it is still yellow pine exposed flat to the sun and reacts the same as regular pt pine to a minor degree. Splits and Cracks in a short time. It is an inbetween price not as high as South American or Man Made but requires a pre drill.

I cant see using it. outside anyway. John

Thanks, John