SilverBox
ArboristSite Guru
So I'm considering putting PP 1" thick as the subfloor for the upper story of my barn/shop. What do you all think>? The joists will be rough cut doug fir 2x6s on 16" centers.
Ponderosa Pine for sub floor
- Thread starter SilverBox
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Sawyer Rob
Addicted to ArboristSite
If it was me, i'd go thicker, at least 5/4... What do you plan to go over it?? And what will it have to carry??
Rob
Rob
SilverBox
ArboristSite Guru
Nothing over it, gonna put a bunch of junk on it, storage. I ran it thru the beam calculator using grade 2 PP and it said anything over .70 inch would be thick enuf using 50lb/sqft for the calcs which is way more then its ever likely to be loaded. Grade 2 DF was good at something like .55 inch thick.
Sawyer Rob
Addicted to ArboristSite
You said "subfloor", and a subfloor is the floor under the finish floor, at least that's how it is here... So, i wondered what was going over it for a "finish" floor... If it's the finish floor, it would encourage me even more to go 5/4.
Anyway, i'd still go 5/4, and the reasons are... You never know what you may want to do with the space in the future, or what someone else may want to do there...
Perhaps there the pine is all nice higher grade lumber, but around here it isn't. You won't have to worry so much about grade with 5/4... If it has a few extra knots, it won't matter too much...
And i do like to over build a bit. In my life, i've yet have been unhappy because i over built something, i can't say the same about under building though... Then again, perhaps this space is so small it really doesn't matter??
DM
Anyway, i'd still go 5/4, and the reasons are... You never know what you may want to do with the space in the future, or what someone else may want to do there...
Perhaps there the pine is all nice higher grade lumber, but around here it isn't. You won't have to worry so much about grade with 5/4... If it has a few extra knots, it won't matter too much...
And i do like to over build a bit. In my life, i've yet have been unhappy because i over built something, i can't say the same about under building though... Then again, perhaps this space is so small it really doesn't matter??
DM
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SilverBox
ArboristSite Guru
Well I consider the material riding on the joists the sub floor, I "could" put another layer over the PP subfloor, but I don't plan to. The logs I have in mind to make this are pretty good, shouldn't be to knotty.
Backwoods
ArboristSite Operative
I agree with using 5/4 or heavier even if it is JUST for storage.
SilverBox
ArboristSite Guru
Come on you guys... look at this..
1" board 8" wide
Me standing on a 5' span not 16", 5 FEET
At 16" it doesn't even think about flexing as its already double what my beam calculator says it needs to be at 5/4s its 4x stronger then the beam calculator says...
1" board 8" wide
Me standing on a 5' span not 16", 5 FEET
At 16" it doesn't even think about flexing as its already double what my beam calculator says it needs to be at 5/4s its 4x stronger then the beam calculator says...
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Backwoods
ArboristSite Operative
yep, four times as strong is a good thing, not a bad thing.
BIG JAKE
Let’s go Brandon!
Either one will work but I believe I would go with 5/4. A little extra meat to account for variations in the milled board thickness. I tend to be an overkiller also. From the pic, the board is adequate. As was posted earlier the extra thickness should take care of any knot worries as it is the knots that will kill the strength in any board. Now if you were to overlay the subfloor then 3/4 would work. Consider that a load unmoved over time will often cause a board to bow. Nice lumber, beautiful spot, and a little hair of the dog!
excess650
Addicted to ArboristSite
My dad built a small barn back in the early 70's. The upstairs floor was planed 1x12 pine(3/4"), and we loaded it with hay and straw. It never sagged or felt spongy, but had more than 2x6s for joists. The joists is where you need strength, unless the spans are really short.
Streblerm
Addicted to ArboristSite
So I guess the Yellow pine T&G 2X6s that I salvaged from an old horse barn are way overkill for the storage in my "loft" (common trusses 24" OC).
They sure did make the whole building more stable though. Talk about top cord bracing.
OTOH, my garden shed has 1/2" osb over 2X6s which I find to be sufficient to hold anything I can carry up a ladder, or hoist up over my head.
They sure did make the whole building more stable though. Talk about top cord bracing.
OTOH, my garden shed has 1/2" osb over 2X6s which I find to be sufficient to hold anything I can carry up a ladder, or hoist up over my head.
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Sawyer Rob
Addicted to ArboristSite
SilverBox
ArboristSite Guru
It wasn't made up. Its still not, I made the test board to check it out. I might slab off one at 5/4s and see what it feels like. Also Big jake has me thinking the 5/4s might give me more shear strength to keep everything nice and square, although I think the shear from 4/4 will be ok. I am going to lay the PP at a 45 to the joists.
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SilverBox
ArboristSite Guru
I punched that into the beam calculator as well, and grade 2 doug fir rough cut 2x6s will work on 16"s, so will store bought 2x8 (1.5x7.5), but store bought 2x6 will not, at full load they deflect more then the X/360 allowed for floors using a load of 50lb/sf, which is way more then that storage area is ever going to see, the main beam that the joists ride on is supposed to bear something like 8,800 lbs by my math (its 16x11x50=8800 lbs), I doubt I'll ever have more then 2-3000 lbs up there.
redprospector
Addicted to ArboristSite
I was leaning toward the opinion that it realy wouldn't make much difference, untill you said you were going to lay the sub floor diagonal (45*). Laying the floor diagonal your floor boards will be spanning more than the 16" that your joist are laid out at. I've laid several sub floors diagonally with the finish floor perpendicular to the joist, but they were way over the 50 lb live load you're talking about. So I guess I'm still not sure it makes any difference between 4/4 and 5/4 since I've never built anything for a 50 lb load.
I built a 12' x 16' portable building to store my wood working equipment in. I used 3/4" for the sub floor (diagonal), and 3/4 for the finish floor (perpendicular) and it's h3ll for stout. But you may not need that much.
Andy
clearance
Addicted to ArboristSite
You got that right. Don't ever skimp on joist or rafter size. Not saying you are because I don't know the span, just saying.
sawyerloggingon
ArboristSite Member
What I want to know is why is their a bottle of whiskey and a shot glass in your work area? Looks like something I'd do.
SilverBox
ArboristSite Guru
What I want to know is why is their a bottle of whiskey and a shot glass in your work area? Looks like something I'd do.
Cause it was the end of the day and a couple friends were over!!
I was showing them how a chainsaw mill works, they thought it was pretty D*mn cool. They were admiring how straight and uniform you could make a 1" board with a homemade "rig"..SilverBox
ArboristSite Guru
I actually calc'd it using a 22" span just because of the 45 degree layout. grade 2 pp is good at .7 inches thick. grade 1 (which I would say that first test board I slabbed off at 1 inch is) is about 3 times stronger then the calcs say it needs to be. A 22"x8"=176 sq/inches=1.22 sq/feet = 60 lb load. I'm 180 lbs and at a 5' span it doesn't break (my friend who is 210 stood on it also and bounced up and down a bit, it deflected more then with me on it, but didn't break), it does flex quite a bit, but its a 5' span. Later today I'm going to slab one off at 5/4 and see what I think.
Metals406
Granfodder Runningsaw
It sounds like you are going old school with your layout... Do you know why carpenters ran subfloor @ 45° to the joists? It was to avoid a running-seam, just as you do today with modern building materials. Some would say it was also stronger for lateral loads. You might even consider bridging... It will really tie everything together and spread/transfer loads.
I've seen turn of the century homes here, with two layers of 4/4 subfloor ran in a lattice pattern, then finished with pine 4/4 T&G. The joists were rough cut pine or fir, usually 2"X12" (actual not nominal)... I've seen some old buildings with joists 3"X12"... You wanna talk about strong! Grandpa didn't mess around!
Those carpenters didn't have load calcs, or engineers, or specs (They did have a crapload of common sense). It would've gone something like this... "Hey Jeb, ya think we could park the wagon on this thing loaded with hay?" "Yup, probably three of'em."
I heard an old saying at some point in my carpentry career... "If it looks strong, it is strong." Good saying.
I've seen turn of the century homes here, with two layers of 4/4 subfloor ran in a lattice pattern, then finished with pine 4/4 T&G. The joists were rough cut pine or fir, usually 2"X12" (actual not nominal)... I've seen some old buildings with joists 3"X12"... You wanna talk about strong! Grandpa didn't mess around!
Those carpenters didn't have load calcs, or engineers, or specs (They did have a crapload of common sense). It would've gone something like this... "Hey Jeb, ya think we could park the wagon on this thing loaded with hay?" "Yup, probably three of'em."
I heard an old saying at some point in my carpentry career... "If it looks strong, it is strong." Good saying.
