Hello 955reber,

Alaska is definitely a climate where not a lot of material really lasts, specially if you are near the coast like you are. There are several factors that any deck will encounter in Alaska including snow, humidity, salt, freeze and thaw cycles through the seasons and of course the normal the normal wear and tear of use.

Because of the factors mentioned above, domestic wood would not be a great option for you because of the amount of maintenance that you'll be having to do every year including sanding, stripping, and resealing just so that the wood maintains it's structure stability.

Your other option that you mentioned was Trex. The trex line has a lot of different products and to better suit what you're looking for you'll have to be going with the high-end materials because of the PVC coating. This will drive up your cost significantly. Other things to consider with Trex is that if the surface pvc coating is gouged or damaged, the interior composite is going to suffer the same problem as wood because it has wood particles mixed in. So you'll see mold, mildew, freeze and thaw as well. One of the major problems with this is also that the whole boards need to be replaced if there's any damage because it can't be sanded off like regular wood. Replacing the board presents also another challenge because you'll need to keep the inventory tag from where your boards came to ensure that the color will be the same when the new board arrives.

Finally, we hit the Brazilian hardwoods. These woods are probably the best option for you and although it may be high in price as well and, it will last and perform better than any other material. Ipe in particular is a very dense wood that water penetration doesn't occur and hence there's no need to waterproof every year. Like any other deck material, you'll need to regularly sweep it down, and hose it down with water to keep it nice and clean. Unlike Trex, if anything were to happen tot he surface of the board, you can just sand it down and it'll bring back the wood, no need to replace the entire board. Maintenance on an Ipe deck is minimal, aside from the regular sweeping, just an application of Oil every year is required to maintain the color.

Hope this helps you out in making your decision!

Second what @AdvantageLumber.com said on IPE. Here in Maine whenever we can we install IPE. It is very dense and durable and looks great whether you apply oil or let it weather. Make sure you use good quality fasteners preferably stainless steel.

Ipe, Ipe or Ipe. Do not use Massaranduba. Ipe is numero uno, Tigerwood, Garapa, Angelim Pedra, or even Cumaru, depending on your spans and overall look. Also depends on your fastening method. But I would strongly oppose composites or crap wood.

Hey also check out this article:
We compare the specs on various decking materials.
http://edeck.com/blog/comparing-decking-material/

You really have to look at all the options and figure out what balances cost and maintenance based on your budget. Garapa is a good low maintenance low cost hardwood but it all depends on what you are looking for.

We just built an Ipe deck in NY. We love it - it has a beautiful color and it has an expensive look - which it is, more than Trex in my area. You do need to oil or seal it if you want it to retain the reddish color and not weather to grey.