Traditional Douglas Fir vs. Hem Fir Lumber

I am laying out the details of my wife's new garden arbor, and have a question regarding my choices of lumber. While I'd love to use redwood, we're not lucky enough in Virginia to have it stocked on the shelves of every BORG in the neighborhood. ;) I could use white cedar, but I have a few hundred dollars in HD gift cards, and was hoping to just buy my dimensional lumber there, and mill it myself. My local HD does not stock traditional douglas fir, but does stock something called "hem fir". I'm assuming this is some sort of hybrid using hemlock and douglas fir? For those that know, can I use this "hem fir" on this outdoor arbor project and expect the same/close results as I'd get using straight douglas fir?

FYI...I plan to stain, then topcoat the arbor with General Finishes' Outdoor Oil.

Thanks!!

- Keith

"hem fir" means it might be hemlock, it might be fir - depends on what the mill was cutting.

If you see a 2X4 marked "SPF", that means "spruce pine fir", and it could be any of the above.

Keith,

After a bit of googling, I found a thread on boatdesign that stated:
"Be aware that SPF is not all spruce, it is a category of lumber that could include any of the following: Alpine Fir, Balsam Fir, Black Spruce, Englemann Spruce, Jack Pine, Lodgepole Pine, Red Spruce, and White Spruce.

SPF(south) could include: Balsam fir, Black Spruce, Englemann Spruce, Jack Pine, Lodgepole Pine, Norway (Red) Pine, Red Spruce, Sitka Spruce, and White Spruce.

And just for the record, Hem-Fir includes: California Red Fir, Grand Fir, Noble Fir, Pacific Silver Fir, Western Hemlock, and White Fir.

DF-L includes both Douglas Fir and Western Larch

These are categories of woods since separating species in the field is too difficult, and unreliable after it is milled, so the group whole stands of mixed timber. The only way to know what your are getting is if it labeled with a single species like "Sitka Spruce" or "Western Hemlock", or if you take it to a wood laboratory where they identify it at the cell level.

These come from the publication "National Design Specifications" by the American Forest & Paper Association.

No worries however, for noncritical applications just pick out something clear of defects, with strait grain, and fairly light and it should serve you just fine. Or slightly oversize the spar for extra strength if in doubt"

I know this doesn't totally answer your question, but hopefully it helps.

You might check to see of they carry cedar. The Borgs around here have some cedar in the fenceing section. I used some of the 2x4 rough sawn material they carry. It might be better suited for outdoor construction. From what I've read Penofin makes some good outdoor finishes too.

My experience as a carpenter was that Hem Fir, was mostly hemlock. Years ago maybe one in 100 boards were fir, now even less. And SPF was just about all spruce. Don't remember ever seeing a fir board in a stack. Now if you want douglas fir, the redish colored premium studs are doug fir. And lumber longer than 20' are usually doug fir. Doug fir was common for joists years ago, when I built my house 30 years ago, the lumber yard had doug fir 2 x 10's so I bought them. And it was less common than years before that. Most houses were built with hem fir joists.

I've always thought that the "red" boards in the Hem-Fir piles were probably fir. Not sure if my thinking is good, but it's what it looks like.

You can use either types of wood in the hem-fir pile for what you want to do, but if you are looking for a rot-resistant wood, dig into the western larch pile. Very rot resistant and quite striking to boot. Much cheaper than redwood as well.

Local Lowes in So. MD has been carrying some 4x4x8 doug fir posts for a while but no so for other dimensions.

Hemlock is much heavier than Fir. Try picking up two dissimilar looking boards of the same size - the heavier one will be hemlock. It also rots much faster than fir which, in turn, rots much faster than cedar or redwood.

I live in the land of Fir and Hem..

Hem - Fir generally means Hemlock ..

SPF typically has some interior fir and balsam mixed in .. but not often D-Fir ..

D-Fir is a bit more valuable, as such, its typically stamped D-Fir .. Loggers can tell the difference.

Hemlock is a wood that absorb's moisture well, its often used in pressure treated. It paints well but is prone to cracking.

+1 on Rick's comment. In the US, hem-fir is Western Hemlock that has roughly the same structural characteristics as Douglas Fir. There is no such thing as a hem-fir tree.

I've been reading up on hemlock. Western Hemlock sounds like an awesome wood if the shake-prone stuff is culled. Wish it grew around here. Our straightest, fastest growing trees around here are ponderosa pines, which is not rot resistant like hemlock and not near as hard. I think I'd like a hemlock floor in my shop. ;)

Todd

Around here (NW NJ), hemlock is traditionally used for barn siding.
Economically priced, hardly moves, rarely cups or warps in full sun, turns black on its own eventually, just like you see barns in the old tobacco ads. A barn with black wood siding.
As Rick Fisher notes, can be splintery when working.
But nothing special if it goes below grade.

White cedar is a better choices if you have the $$. Below grade works well, especially if you can set the posts in gravel. More suited for joinery (lap joints, etc) than hemlock.
But you can stain either wood any color you want. Anything that goes below grade, stain it heavy coats.

Thanks for all the great information, guys! I really appreciate it.

- Keith