Floor joist sizing

I'm replacing the lower level floor joists in a 135 yr old farm house. Basically sitting 6" off the ground on a rock foundation. The current joists (what's left of them) are rough oak 2x10 on 24" centers. Length = 15.5'. If I go to 16" centers and support them in the middle, would a 2x8 Douglas Fir be sufficient, or should I stay with the 2x10? Flooring will be underlayment then 1x6 pine planking. (similar to original)
THANKS,
--
Steve Barker





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2x8 habitually spans 12 feet so with support in the middle and with points of inflection out from the center support, you have only about 5 - 6 foot of span. So, sure.
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thanks for the reply. that's kind of the way I was thinking.
--
Steve Barker


"Glenn" < snipped-for-privacy@kc.rr.com> wrote in message
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I had posted earlier but stoopid google-groups seems to have failed so will make the comment again...
I had suggested I'd stick w/ the 2x10 but hadn't noticed the mid-point additional support so agree with that a 2x8 is sufficient.
What I would add is that at least in a significant part of the country trying to get a 16-ft 2x8 in Doug Fir would be like buying the equivalent in FAS hardwood for pricing if could get it at all. For the purpose, I'd probably just go P-T for the extra protection from moisture and chewy critters at what would probably be half the cost or less. (I tried to get some Doug Fir 1x for some restoration work here to match some existing work and the local 'yard counter flunkies said "Fur? What's that? -- Oh? Never heard of it." :( )
Steve Barker LT wrote:

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2x6 would span the 5'-6" on 16" centers
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Agree, strength wise but I would stick with the 2x8 because I believe it would be a more stable piece of wood. Yellow pine is just as strong and more plentiful but block it from warping/twisting..

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Thanks for all the replies. I think I'll stick with the Douglas fir as it is cheaper than PT here in Kansas City. If it took 135 years for the originals to rot, then the DF should more than last the rest of my life. I'm sure when I'm gone the house will be dozed for development.
--
Steve Barker


"Glenn" < snipped-for-privacy@kc.rr.com> wrote in message
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Hey KC. I'm in Shawnee
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Stilwell and moving to Paola here. <G>
--
Steve Barker


"Glenn" < snipped-for-privacy@kc.rr.com> wrote in message
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Hey There Kansans
I was wondering what the direct applied stucco (DAFS) market was like near you? Kansas City seams to be a huge stucco market!! Especially with the real stuff but I didn't know if anyone was using the direct applied. Any feedback would be great!
CB~

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My experience with it is about zip but it is used a lot around here.

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I'm not familiar with the term. Yes, there is a lot of stucco used here, but all I know is what I observe. An expanded metal type product is nailed up and the stucco applied by hand with trowels.
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Steve Barker



"cb" <your snipped-for-privacy@hotmail.com> wrote in message
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Steve Barker LT wrote:

Liberal, here...and, not MO! :)
You can get Doug fir in KC for less than PT??!!! From whom, may I ask? I could get it through Star in Wichita was closest other than Amarillo but only as special order for a premium from either last time I checked. If I knew where to go, I'd probably make a planned excursion on a family visit but bring the big truck or trailer instead of pickup or car even though it's nearly an eight hour trip that way.
I agree that it will certainly last as long as not direct ground contact. Wonderful stuff, 'tis.
Ya' know, one other thing struck me as just a thought--if there isn't anything but the low crawl space and you're going to block/support in middle of span anyway, maybe use eights instead of 16s simply for the ease of handling in a cramped space? Particularly if you're working alone might make the job a lot easier. Just a thought I figured I throw out...
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Lowes and Home depot. Check their website and put in 66061 for your zip code.
I considered using two 8's or even an 8 and a 10 overlapped. But the 16' er's are nice and straight at my local store and I'll have help.. With all the walls down to studs, there is no problem carrying them through the house. <G>
--
Steve Barker



"dpb" < snipped-for-privacy@swko.net> wrote in message
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As mentioned the spans on the 2x8 with support in the middle appear adequate, but I'd be very concerned about that "rock" foundation. In California, we bolt down to the foundation very carefully, and given the chance of tornado or flood, I'd do the same in Kansas, I suppose. The supporting posts can settle too, and then you'll have an uneven floor.
DF is rated better than any pine for supporting members, but as mentioned too, it's worth painting them with some kind of termite/rot resistant preservative especially since your current joists apparently are rotted out. On the other hand, I think that for the complete span without mid support, the 2x10s might not even be enough. Check the Canadian DF charts which are available on the web. I forget the link, but it can be easily Googled.
What's the underlayment? I'd use plywood, not that glue-composition board stuff, and glue & screw it down to avoid creaking. I'm also using old 1x6 DF planking for a floor in an new room above the garage, but felt that I should run the edges of the boards over a router first to create something of an overlap/tongue groove effect to hide the finishing nails, get a tighter fit, and also avoid any sort of creaking in the future. Between the plywood and subflooring, it seems to me that some kind of roofing felt would also be wise, or that special plastic stuff used below hardwood floors these days.
Are your pine floors painted or stained? Since my recycled DF is discolored in places from nail holes, I figure that I should seal and paint for a better look. But, I don't know what kind of paint to use on a floor. I'll want a water-based paint, but I want a very durable finish too.
Steve Barker LT wrote:

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After seeing it at my wife's cousin's house in NH, I believe we'll paint or sponge paint the floor planks. She has one room that is merely plywood with the seams carefully filled, sponge painted and bordered, and it looks like a carpet until you get practically on it.
BTW, the original 2x10 were supported (if you can call it that) in the middle. They had a 2 x 6 laying on it's side running the length of the room, with a few rocks under it. LOL!
As for tying down, I rekon 135 years in the alley and it's still there. AND we're on a hill to boot.
--
Steve Barker

"Alan" < snipped-for-privacy@gmail.com> wrote in message
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