Chainsaw milling "structural" oak flooring

[ballen]

Hi,
I have benefitted tremendously from the expertise on this forum.  It is much appreciated.  I've never asked about this particular subject before. Some background:

I have standing dead oak...probably red oak but could be white. The bark is completely gone so it's been standing dead for a while but, based on a few that have fallen, the centers are solid.

I am building a nice-ish, small, 2 story, timber frame, recreational cabin. (12'x22') (discussed on the timber frame forum). It is not subject to any building codes, but I do want it to last!

The second floor is supported by timber joists, approximately every 4', give or take.  
I'd like the 2nd floor flooring to be the only "floor" since it will be visible as the ceiling from the first floor.
Several questions:

• How thick should the flooring be to be the only support as the second floor?  I'm guessing 2".
• Any harm in milling as wide a plank as possible?  I don't mind random widths as flooring and seems a shame to rip down a 16" wide plank if I have them from my trees.
• I'm assuming tongue and groove is the best way to join them?

I have successfully chainsaw milled 4x4" for use as framing in the cabin. (the big timbers are salvaged 1840's hand hewn). Wondering if I can do the flooring too.
My alternative is the 2" hemlock salvaged from the barn but I'm thinking the oak might be better?
Any comments/advice are greatly appreciated.

[Ljohnsaw]

With your joists at 4' centers, the foor might be a bit bouncy with 2" floorboards.

Take look in the Toolbox. I think there is an appropriate calculator to help. My guess would be closer to 3x.

[doc henderson]

Chainsaw will be slow, labor intensive, less accurate with more waste.  is there a band mill nearby?

[sawguy21]

No kidding, I can't imagine trying to mill oak with a chain saw.

[barbender]

 Unless you really like chainsaw milling I'd hire someone with a band mill.

 4' seems to be quite a span for plank flooring but I have no experience with that.

 Whether it is air dried or kiln dried, wood will still move seasonally. Wider boards will have wider gaps. You can use 6" or 8", with many small gaps, or use 16" with fewer but much larger gaps. And if you install 2" air dried, a 16" may get gaps large enough that you can look through the floor to the kitchen below to see what's for dinner😊

[SawyerTed]

Having started out with a CSM, I just can't imagine a scenario where I'd use one to saw lumber especially dry oak.  Of course it's possible and has been done but the return on effort is very small.  

The advice to seek a band mill is good advice.  

[beenthere]

Some open cracks are "good" as the dirt can sift down through to the floor below, thus making sweeping the second floor easier. 

[doc henderson]

there was an oak taken down at a local Christian school.  I stopped by and they said it was spoken for.  the guy with a PU and chainsaw mill was there each evening.  he would get one slab each evening with 3 hours of work.  

[PAwoodhogg1971]

Hi trying to put up a post don't know if I am doing it right look to get into the chainsaw and milling please let me know how thanks

[ballen]

John,
Thanks for reminding me about the calculators.  I'll check them out.  I may even be able to add some joists if I have any matching ones left (they just sit on the girts so easy to add).

All,
I do not have the benefit of a band saw or one nearby (know any in NE PA? Closest town is Hancock NY...I'm 10 miles into PA from there).
Perhaps I'm a glutton for punishment.  I've chainsaw milled many 4x4's from dead oak and it didn't seem too bad.  Perhaps I don't know any better.  I sharpen my own ripping chain and it defiantly doesn't take 3 hours to cut a slab.  Maybe 10 minutes for a 10 footer.

My alternative is the salvaged 2" barn hemlock.  Has anyone ever used hemlock flooring in a residence?

[moosehunter]

I'm only two hours away. Have mill, will travel!!
mh

[Brad_bb]

I'll bet there's a band mill within 5 miles of you.  Places to try to find them...
Woodmizer's prosawyer network
facebook marketplace
craigslist if that's still used in your area
Internet search
talk to local hardwood suppliers, or loggers, or tree guys, or firewood guys.

I don't like floor joists on 4' centers.  Is this already built, can you add joists to get them on 2' centers?  What are the dimensions of the existing floor joists?

I have a second floor in my shop that is like a living space. The floor joists are 6x6 white oak on 2'to 2.5' centers with Doug fir 2x6 T&G(1.5" thick).  This floor was actually laid twice.  After we first installed it, we had shrinkage and gaps opened up the first winter with heat.  I thought it being fir and how long it had been KD and sitting that it would be fine.  Nope, we pulled it all up and re-layed it tight and it has stayed that way.

[teakwood]

I would say 2" for 4' spacing is ok. if you go down to 2' spacing i would use 1" or 1.25", so your oak tree will yield a lot more boards. But i have no idea of the strength of oak. 
It's a cabin, not a high ends customers house

[scsmith42]

Personally, if my choices were limited to 2" barn salvaged hemlock versus chainsaw milling the flooring, I'd lean towards the hemlock.

If you choose to chainsaw mill it yourself, keep in mind the following.  1 - the oak will shrink around 1/8" per inch of thickness as it dries, so if you want 2" rough sawn dry flooring, you need to mill at at least 2-1/4".

Second, if you're planning to plane both sides of the flooring, depending upon the width  you'll want to add at least another 1/8" of thickness per side that you plan on planing.  So if you're going to want 2" thick flooring planed top and bottom, you need to mill green at at least 2-1/2".  And that's if you're using a fairly precise band mill.

But there is a third dimension as well, and that is the inherant inaccuracy of chainsaw mills.  The surface is rough, and probably won't clear up with only 1/8" stock removal.  So now you're looking at milling your pieces around 2-3/4" - 3" green in order to net 2" thickness after drying, face jointing and planing to thickness.  If your flooring strips are pretty narrow (4" or less), then  you can probably get by with less green thickness.  But if they are wide (12"+), you won't be able to.

If the hemlock is structurally sound, you should be good.  Although it is a soft wood, it's modulus of rupture is fairly high when makes it a good candidate for your stated need.

[bluthum]

Without getting into the "whys" very far it sounds like you might want to consider blind splines rather than tongue and groove for your joints. And , generally speaking, narrower boards will make a better floor than wider ones.