Pine or Hemlock Beam For Porch ?

[clww]

I'm thinking of using one solid log/beam across the entire width of the porch I'm going to be building on the cabin. I can use clear white pine or hemlock, which we have on our property. Once the tree is on the ground, I plan to slab two opposite sides flat/parallel with the chainsaw, then de-bark with the draw knife. The beam will be roughly between 24 to 26 feet total length, and between 8 and 12" thickness. There will be between 6 and 8 posts below this to hold up it and the roof rafters for the covered porch. These posts (logs) will be 12" diameter. Roofing material will be steel corrugated roofing. The rafters will be 10 feet long each, 2 X 6, and 16" on center.  Overhang will be 2 feet, so not worried about it getting lots of moisture. The porch will be on the side of the cabin with the least exposure to the sun, but plenty of airflow from the wind coming up the ridge line. According to the FF Tools Calculator, the hemlock will weigh a bit over half a ton.
Thoughts, tips, suggestions are welcomed and appreciated as always. 

[routestep]

I've worked both white pine and hemlock - green, and I couldn't really tell the difference. The color of the wp is a little bit lighter maybe. Heartwood white pine is suppose to be rot resistant, but I had a sawyer tell me hemlock had some rot resistance also. The books don't show that though. Hemlock can tend toward having shakes, so watch for that.

When dry, chiseling cross grain and hemlock tends to crumble. Use a power mortiser.

I think your good either way.

[clww]

Hey there, routstep, and thanks for replying! I secretly thought eventually someone would.
Should I be concerned with any warping or twist to this beam? It's going to be heavy, and interesting getting it in place with very little machinery. By myself, too. ;D
Thanks for your input and experience.

[thecfarm]

I used some hemlock on the wife's veggie shack. I think I used 8-6X6,10 feet long. They are still nice and straight.I used some Norway pine,only about 4 and gave up on them. They was twisting in no time. These was all used green by the way. I would lean towards the hemlock. I did. I have bunches of white pine and have not used any on this building. I had to cut off a few feet on some of the hemlock that I used. I built a horse run in and had no problems with the hemlock. I guess I used all the good ones on the horses.

[clww]

I think I am leaning towards Hemlock for this project. I've got many, many mature Hemlock and White Pine on our property. I don't think I'm exaggerating when I say at least 100 of each species are between 24" and 30" DBH. Several are even larger.  I have one Hemlock in mind that is right off our roadway, probably 150 yards from the cabin. It's fairly clear for the first 50 feet, but is it ever tall! If I take one of these big ones down, I want to be able to use as much of the tree as possible.

[thecfarm]

I have burned hemlock in a wood stove too. It burns good,no runaway fire and will coal down some too. Dry it as any hardwood.

[clww]

So far up at the cabin, I've only burned pine or hemlock that was already dead before I sawed it to length. It burns well, hot, and smells good. Doesn't last very long, though.

[routestep]

So you will have a sill that is on footers. Six posts (I think eight posts is way overkill), four would do as well. A couple of let in braces at least, or maybe four. And your wall plate sitting on top. Use four by six for rafters for looks.

I'd stick with 8 by 8. Eight by twelve for one man is very hard just to turn over on saw horses.

A backhoe could do this if the porch roof isn't too high, like under ten feet, but you need another man to get all the tenons to line up into their mortises.

A couple of gin poles could lift the wall plate also, still need people, block and tackle or chain falls and rope.

You would have to have scaffolding to stand on to do a parbuckle and people.

I didn't have much twist at all in any hemlock that I worked on. The trees are straight then no problem. With the size trees you have, you could have quarter sawn 8 by 8's! No need to box cut.

[Jim_Rogers]

Follow your plan of how you intend to cut the beam for your porch.

I read a book once, it was called "What not to build" or something like that. In it they talk about porches a lot.
Basically the point was that if the porch beam holding up the rafters doesn't look big enough to do the job, and the posts holding that up don't look big enough to do the job, your mind will tell your body that it isn't and you'll get this feeling like your life is in danger if you enter or walk under the porch roof. It is an unknown feeling you have that something just isn't right.

They have developed sizing formulas to size the beam and posts so that this doesn't happen. It is mostly for looks more then for actual strength or support.

When you drive around, look at porches. You'll see some with tiny little 4x4 (3 1/2 x 3 1/2") posts and some with 6x6 (5 1/2x 5 1/2"). And some even bigger 8x8 (7 1/2 x 7 1/2"). When you start comparing you very quickly see the point/difference.

And when you go back and look at the 4x4 ones you'll see how they don't look strong enough.

Jim Rogers

[frwinks]

I have a lot of hemlock in our frame. It likes to grow wonky on river banks so it's  perfect for crucks  ;D.  When green it is a delight to cut, visually it's more interesting than pine.  I was told it's a good choice for outdoor projects as well.

[Jay C. White Cloud]

I would definitely choose Hemlock over pine for this application, and have on several jobs.  Pine would work, if that is all you had, but I agree, Hemlock is visually more stunning than pine when used in this application.  With the live edge, top and bottom, and the rectangular stock of the rafters passing over the top of the beam, you will get a stunning presentation of contrasts, both in color and grain pattern.  There would be nothing wrong with mixing the to species either.

Just from the perspective of affect, as Jim was describing, I would go with visual over what the charts say.  I would also not use 2x6 stock as this could be out of balance, weight wise visually with main carrying beam.  Our most common porch roof rafter is 80 mm to 90 mm square, or 3.5" to about almost 4".  In your case maybe a 3x5 or 3x6 wood fit your taste.  Ours are on 500 mm to 600 mm centers, for you maybe 20" to 24", assuming it does have some pitch and isn't almost one of those flat porch roofs.