Building with wet redwood

[Meta]

I recently purchased some newly milled redwood dimensional lumber from a sawyer, for the purpose of building outdoor planter boxes. The sawyer claimed that I should have no problem building with the wood wet, and do not need to dry it. However, a building contractor thinks otherwise, so I'm looking for third opinions.

I bought common grade 3/4" thick x 12" wide by 8' and 6' length dimensions. The planter boxes are going to be 7 1/2' long, which will come out of the 8' lengths. They are just planter boxes --utilitarian and functional only-- not fine cabinetry or a table top that needs to be perfectly flat. A small bit of warping would be ok. Likewise, shrinkage causing 1/8" or 3/16" gaps between boards along the 7 1/2' lengths would not be an issue, but larger gaps, say 1/4" or bigger, might let the dirt wash out.

The sawyer claimed he has built fences and pergolas with freshly milled, wet redwood, and that I should not have a problem building these planter boxes with the wet wood. He said "it wouldn't hurt" to air dry it for a week, and that because the boards are so thin (3/4") they would dry fast (in full sun mid-coast California) but this isn't crucial.

What do you think?

[thecfarm]

Meta,welcome to the forum. Hang on,someone will know.

[Ianab]

All that's going to happen as the wood dries is that it will shrink a little. Redwood is pretty stable, so the shrinkage wont be excessive. For things like planter boxes, picnic tables, pergolas etc, you can probably get away with using it green, and letting it dry in place. It would be "best" to let it dry first, which won't take long for 3/4" boards, but probably not essential.

Now if you are using it for building a house, you do want it reasonably dry so you don't trap that moisture in the wall cavity when you seal things up. Also you don't want your nice joinery and trim to shrink and open up gaps. This will be where your builder buddy is coming from. He knows not to use green wood for more critical applications.

ian

[GeneWengert-WoodDoc]

I would add to Ianab's comments:

One issue will be fasteners.  When a fastener like a nail or screw is put into wet wood it holds really well.  Likewise, if it is put into dry wood.  However, if the fastener is iron in wet wood, it will corrode and will deteriorate quickly.  Plus, as it corrodes, it will stain the wood, mainly iron tannate which is black.  So, use a fastener that will not corrode.  Second issue is that a fasteners, especially nails and staples, that are put into wet wood and then the wood dries out will suffer a large loss in holding power.  (The same is true for wood that is rained on, dries out, rains, etc.)  So, use good construction techniques for joints and use more fasteners than needed initially.  Anything that you can do to prevent wetting and / or drying out after fastening is very good.  So, in answer to your query, you can use wet redwood with corrosion proof screws, but the joints are likely to loosen a bit as the wood shrinks when it dries, eventually, as the wood cycles through wet and dry, losing a lot of strength.  OK?

[Darrel]

The old growth redwood was very stable from wet to dry and back again.  I'm sure that the planter boxes will be out in the weather so will be going from wet to dry at least once a year.  I'm also guessing that this is not old growth lumber you are working with.  So take a look at the growth rings, if you only have 3 or 4 per inch you will have some real problems on your hands no matter what you do, find a different project for your lumber.    If there's somewhere in the neighborhood of 16 to 20 you should be ok.  If too much less than that, let it air dry first.  If less than 10, be careful.

[Meta]

Thanks for your answers, guys. Very helpful. I plan to use poly coated deck screws. I'll look at the growth rings.