Rough sawn green doug fir for exposed ceiling joists and floor joists

[Sedgehammer]

Hello everyone 

New guy here with some questions with rough circle sawn doug fir, hoping for some help. If wrong forum, please move.

Doing a remodel with a build on. I have framed houses way back in the day and have built my current shop that we are turning into a house and adding onto.

Looking to span 24' with either a 3x12 or 4x12 for ceiling joists 2' oc. 5/8 v grooved t&g for the ceiling and 12" of insulation on top of it. This is going under a current factory trussed roof. Current ceiling is 12', this will be 10' 6" to t&g, so 18" gap. I could tie into the above trusses if needed. 

Looking to span 20' with either size for floor joists. 2' oc 5/8 v grooved t&g for the ceiling and 5/4x6 spaced 6" with pex heat in floor with 3/4 wood floor above.

Can go to 16" oc if needed, but might look a little busy with them spaced so closely.

Will be staining the timbers dark and clear coating the t&g for contrast.

Thanks

[Don P]

Hi Sedgehammer,
I seriously doubt the existing trusses were designed for you to tie into them.
The toolbox icon, left column of the page, scroll to the bottom and click it, Click on the beam and column link near the bottom of that page. Then click on the simple beam 2-4" thick drop down species list calc.

your ceiling joist load sounds like 15 pounds per square foot would be conservative 2' wide x 24' long x 15psf= 720 lbs load per ceiling joist. finish the entries and click show result

The floor joist load is going to be 40 psf live load + 10 psf dead load for a total of 50 psf x 2' spacing x 20' span... and run with it. Holler if you get stuck.

[Sedgehammer]

Hi Don, thanks a lot!

No they weren't, but I also removed the ceiling load from them, so that amount would be available

Using #2 Doug Fir Larch. Will be getting mix of, so can one expect average of #2's or #1's or....

3x12 passes on ceiling with shrink to 2.5"x11.25" easily

3x12 passes for floor joists as rough cut, but shrink at 2.5x11.25 doesn't........ 2.75x11.25 does though, so it's marginal

4x12 with shrink to 3.5x11.25 passes easily on floor joists

Do you use as is dimensions or expected shrink and perhaps my shrink is too much or using #2 is too much worst case?

Thoughts?

Your calculator is the first one I have seen that allows one to add width or depth to span calculations and I've been looking for a long time. Really appreciate it!

[Don P]

That's why I wrote them, its from standard equations, sawmillers get into different dimensions and species.
Use the sawn dimensions, no need to allow for shrinkage, I'll dig up the footnote and post it here. Your shrinkage estimates are overshooting what it'll actually be. All that said there is nothing wrong with being conservative. Around here we tend to use #2 numbers, again conservative. I talked to a TF engineer who said not to be afraid of using #1 numbers as most of us won't actually use a #2 timber because of aesthetics... he's way more experienced than me but having been around I'm not so sure of that one

[Sedgehammer]

Yup, but just couldn't find it before

Then 3x12's will work all around

Was thinking I was overshooting it, but didn't really know. This forum is a great knowledge base for stuff like this I can see

I usually go conservative also, as better to be safe than sorry

Problem I'll be possibly facing is it will be a custom order, so not sure to what extent I'll be able to sort all that much

I'd have to agree with you on the engineer..... Life's realities tend to be all too hard.....

Thanks again!

[LeeB]

How does one deal with shrinkage when usin green floor joists? Are the set proud of sill beam?

[Don P]

Spanking a horse I've beat to death, don't build green if you can help it. Although we can predict average shrinkage nobody told the boards to all hit the average. Shrinkage of an individual piece is not the same as average.

If the joist is on top of the sill, a dropped girder, or if the sill is the same moisture content as the joist if its a flush girder then that would be best. Even in stick framing if you have 19% moisture joists butting into an LVL made of very dry veneers it is good practice to run the joists a little higher than the girder.

I'm glad you had me take another look at the footnotes Sedgehammer.

1. Lumber Dimensions. Tabulated design values are applicable to lumber that will be used under dry conditions such as in most covered structures. For 2" to 4" thick lumber the DRY dressed sizes shall be used (see table 1A) regardless of the moisture content at the time of manufacture or use. In calculating design values, the natural gain in strength and stiffness that occurs as lumber dries has been taken into consideration as well as the reduction in in size that occurs when unseasoned lumber shrinks. The gain in load carrying capacity due to increased strength and stiffness resulting from drying more than offsets the design effect of size reduction due to shrinkage.

Table 1A;



So for our purposes deduct 1/16" from the green thickness for the number you enter in the calc and deduct 1/4" from the green face width for your input depth.
To round this out, when using timbers 5x5 and larger use the green dimensions from Table 1A, in other words your actual dimensions, that is the footnote I was misapplying to your dimensions. All of this is in the "Supplement to the NDS" available as a free download at awc.org.

[Sedgehammer]

Them horses......  

My use of them is purely an economical one. I can source the green for about 1/3 the green....

Floor joists will go on top of a 'dried' sill and the ceiling joists will go on a 2x6 cut into the existing 2x6 studs horizontally. With that in mind, how would you make the 'dried' sill plate where the joists will sit on?

Also how would you marry the 'dried' 2x12 that will be nailed across the ends of the green floor joists, as the floor decking and upstairs studs will be sitting on both the green floor joists and the 'dried' 2x12 that runs across the ends of the floor joists.? 

I'm expecting some drying to occur, as I am going to try and get them a few weeks before I actually need them. Dry stack them inside and run 2x4 spacers both vertically and horizontally and then ratchet strap them together. With that said, I've done a lot of expecting that didn't spec out.....

I'm glad I made you work for your voluntary postings.....

Still passes with those different specs

On 10x10 timbers one can expect about 1/2" shrink based on the table or would it be more since it's 2x the size listed?

Also, if using the 10x10's for porch posts that would have ground contact and encased in crete, if one used insecticide when placing, any idea on life expectancy?  

Thanks again for your info!

[Don P]

I wouldn't expect more than 1/4" of shrinkage, I'd set the dry rim joists 1/4" lower than the green ones. You can notch in a rim if it doesn't compromise the frame, set posts alongside studs under the joists if notching would compromise the existing frame. A 10x10 won't shrink more than a 2x12, in fact it'll probably shrink less because internally it is more bound up on rays, radial grain, and is more apt to have its shrinkage show up as a check rather than overall dimensional change. In other words a big timber is going to experience shrinkage but if the shrinkage presents itself as a check the timber won't lose the amount of dimension the shrinkage created.

There's part of the reason I post, it brings up stuff that makes me dig, we both learned  

Ground contact of untreated isn't good, encasing it in concrete that keeps it wet is worse. How long it'll last depends on moisture available, temps, species, density, heartwood sapwood, and on and on. Short answer is it isn't a good idea. Another dead horse I'm going to get beat up on, I'd soak them in borate, like submerged in a tank for as long as possible.  Then dry, clean the surface residue and coat with a water repellant preservative. Borate will leach out into the concrete or soil and protection will be lost over time, not over a short time but it's certainly not fixed within the wood. It would be better decay wise to set them on top of masonry that extends above ground. That opens up a lateral stability and uplift problem that needs to be looked at. Seems there's never a free lunch.

[Sedgehammer]

All joists will be green

Have to build a 18" knee wall to the existing 8' wall (as increasing ceiling height 18"), so can make this 17.75" instead of 18". Then just nail the 2x12 that boxes in the joists and just run with it?

Am going to fir out the existing studs by 1.5" with a 2x4 nailed center on the studs anyways, as going with 8" insulation.

Read same about checking vs shrinkage in some other posts also



Yeah, I know it's not the best idea, but 10x10 green treats are $200 

Doug Fir, central OK, fairly dry

Would use 9.1% Fiproni, lasts 10 years or more. Not a big chemical fan, but for termites, I'm open to what ever kills them the longest.

Yeah but lifted masonry is costly.... 

Nope and free advice many times is *DanG expensive......

[Don P]

Use a 2x6 nailed to the face of the existing stud and extending over one side. Then that flatways 2x6 is completely under the 4x joist. Extend the joist alongside the current stud and nail from the existing stud into the joist, doesn't hurt to block between joist and the next stud to prevent roll and fireblock the passage between wall and floor and level above.

Replacement is costly too, just weigh your options. 8x8 treated posts here are ~$200, yeah, no fun.

[Sedgehammer]

If'n i'm understanding you properly. Nail a 2x6 under the DF RC floor joist to the top sill plate and the stud, then nail a 2x6 vertically to the stud under the horizontal 2x6. Good idea on the 2x6, but will possibly still use 2x4 the goes vertically. It's all doug fir, so the strength should be ok. Have to have room for wiring and related in the wall behind it.

As to roll, that's what the rim joist is for isn't? Maybe I'm getting my terms mixed up? But we will be putting blocking in between them and sheet rock will run up to the blocking and the bottom of the joist.

So just want to make sure on the green joist face depth (12" as cut) vs the dried rim joist (11.5ish). Your saying to notch the bottom of the green 2x12 a 1/4" where it'll sit on the sill plate and leave a 1/4" above the dried rim joist for shrink?

Any advantage to using a green rim joist instead of a dried smaller one?

As to the posts. Thinking to set them above ground and on a green treated piece of wood or on some type of vapor barrier and pour the crete around them. This eliminates the wood from sucking up moisture from the soil, but being in the crete gives me stability. Set on the masonry piers gives me little hold down and we are in tornado alley.

Thanks again

[Sedgehammer]

Also, anyone have any idea on how long one must wait before applying a product such as ready seal to the beams? 

Does it just need to be dry on the outside, or pretty fully dried?

Going with a clear coated pine ceiling above the exposed joists, so wanted to make the beams a dark brown for contrast.

Thanks

[Don P]

If'n i'm understanding you properly. Nail a 2x6 under the DF RC floor joist to the top sill plate and the stud, then nail a 2x6 vertically to the stud under the horizontal 2x6. Good idea on the 2x6, but will possibly still use 2x4 the goes vertically. It's all doug fir, so the strength should be ok. Have to have room for wiring and related in the wall behind it.

That would work fine. I was thinking of just a vertical 2x6, no horizontal nailer. Nail the 2x6 flatways to the studs so that it sits under the joist. The joist extends across the 2x6 and alongside of the 2x4 stud and is attached to it. But either will work if I'm understanding you correctly.

As to roll, that's what the rim joist is for isn't? Maybe I'm getting my terms mixed up? But we will be putting blocking in between them and sheet rock will run up to the blocking and the bottom of the joist.

I was proposing between the 2x4 studs run 4x12 blocking between joist and stud. Yes a rim restrains the joist from rolling by end connection, a solid block wedged between will help while things are drying and also provide fire blocking. Just make sure flame cannot get from wall to floor or from floor to floor, no chimneys.

So just want to make sure on the green joist face depth (12" as cut) vs the dried rim joist (11.5ish). Your saying to notch the bottom of the green 2x12 a 1/4" where it'll sit on the sill plate and leave a 1/4" above the dried rim joist for shrink?

What I described then doesn't need a bottom notch simply set the top of the green joist about 1/4" above the top of the dry one.

Any advantage to using a green rim joist instead of a dried smaller one?

Shrinkage would be closer to the same.

As to the posts. Thinking to set them above ground and on a green treated piece of wood or on some type of vapor barrier and pour the crete around them. This eliminates the wood from sucking up moisture from the soil, but being in the crete gives me stability. Set on the masonry piers gives me little hold down and we are in tornado alley.

That works when new but if the bottom decays in 5 years you are back to an uplift problem. If you set a steel knife plate in the concrete or a rated connector with a standoff to get the bottom up you'll have the best of both worlds.

Thanks again

Film forming finishes like Sikkens, paint, poly, etc, the wood should be dry before finishing. Generally I don't much care for those types of finishes on heavy timber. A breathable finish can go on to wood that is not done drying because moisture can still escape from under the finish. Do check with the manufacturer first though, most have an 800 number.

[Brad_bb]

I've read the original post and can't say I really understand it all.  Pics are worth 1000 words.  I will say this though:  It's fine to timberframe green.  I wouldn't have a problem with a floor joist that it 8x8 or 8x10 green, but such non symmetrical dimensions like 3x12 or 4x12 may crown quite a bit while drying.  That will screw up a floor or ceiling attached to it.  If you want joists like that, or even 2x material, it needs to be dry before install.  I know that Doug fir is radio frequency KD'd from some suppliers.  If it's your own wood that you're milling, I'd mill it oversize and let it air dry for a year, then put it in conditioned space for 6 months to get a lot of the movement out of it, then check the MC and see where it's at.  When you use symmetrical sticks green, and they must be boxed heart, they are more likely to dry more symmetrically.  They will check on one face primarily and have some movement, but less likely to crown/bow. Even so, if you are using timbers as floor joists, you typically want to give them time if you can to see if they do move, a year if you can.  Then you can correct for that initial movement.

I installed DF T&G 2x flooring in a loft without checking the MC back in 2016.  Well it shrank and we have some significant gaps now.  And it was nailed down, so taking it up would destroy it.  Unfortunately dimensional DF that this flooring started from is allowed to be KD down to 20% and sold as KD.  Hardwood is typically dried down to 6-8%.   So you have to beware and check the MC and make sure it's down to at least 8% before installation on any T&G.

[Don P]

I've used FOHC, free of heart, 4x12 dougfir quite a bit in roof framing. It generally comes green. My Dad built stick frame homes with plank and beam roofs, he got his start at Deck House in 1959 as shop foreman working for a couple of MIT grads, Bill Berkes and Bob Brownell who had spun off from Techbuilt/ Acorn Structures, a little history of the company and some pics of those roof designs here;
https://www.deckhouse.com/about-us/our-history/
When we moved back south in the late 60's Dad and one of the Deck House office managers started their own construction company. Deck House had used mostly solid sawn 4x12 dougfir. It mostly worked well, structurally it was fine and as you can see in the pics on their website the beam spacing was often 8 to 12' on center. The roof planks were typically 2-1/2" thick T&G. Dad and his partner had noted the source of callbacks and disappointment were mostly moisture related. Most often it was drywall cracks and gaps around the fir beams as they shrank and sometimes twisted. The company was also cantilevering floor beams out to form "floating" decks, those were a constant source of problems. The glulam industry was broadening. Dad and his partner switched to glulam 4x12's and face laminated planks, both of kiln dried material, and the callbacks disappeared. Although still a hard few days stacking the roof it was much better than it had been! When I went out on my own and began building log homes a number of the roof designs were green dougfir 4x12's, typically on 4' centers with 2x T&G roof planks. Ours were nestled into wood or log blocking, so no drywall to crack. I cantilevered one deck at a client's insistance and Dad lectured me hard, that deck was a callback later, lesson learned. I prefer glulams as they are stronger and more stable but customer preference was for solid sawn. On serious structural ridges they pretty much had to be thicker and deeper glulam but were generally 25'+ or so above the floor so really all you could see was the bottoms well. I don't recall any real crowning problems in any of that, Dad's or mine. I suppose the planking tends to hold them in plane. Anyway, there's a bunch of it out there and I doubt its a real problem. For more details on that method of construction take a look at the publications tab at awc.org, there is a brochure on plank and beam, I think in their DCA series of pubs.

[Sedgehammer]

I've read the original post and can't say I really understand it all.  Pics are worth 1000 words.  I will say this though:  It's fine to timberframe green.  I wouldn't have a problem with a floor joist that it 8x8 or 8x10 green, but such non symmetrical dimensions like 3x12 or 4x12 may crown quite a bit while drying.  That will screw up a floor or ceiling attached to it.  If you want joists like that, or even 2x material, it needs to be dry before install.  I know that Doug fir is radio frequency KD'd from some suppliers.  If it's your own wood that you're milling, I'd mill it oversize and let it air dry for a year, then put it in conditioned space for 6 months to get a lot of the movement out of it, then check the MC and see where it's at.  When you use symmetrical sticks green, and they must be boxed heart, they are more likely to dry more symmetrically.  They will check on one face primarily and have some movement, but less likely to crown/bow. Even so, if you are using timbers as floor joists, you typically want to give them time if you can to see if they do move, a year if you can.  Then you can correct for that initial movement.

I installed DF T&G 2x flooring in a loft without checking the MC back in 2016.  Well it shrank and we have some significant gaps now.  And it was nailed down, so taking it up would destroy it.  Unfortunately dimensional DF that this flooring started from is allowed to be KD down to 20% and sold as KD.  Hardwood is typically dried down to 6-8%.   So you have to beware and check the MC and make sure it's down to at least 8% before installation on any T&G.

Pics will be a comin once the work has been a startin.
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All RC DF will be comin directly from the mill. Circle cut. I am hoping that I can get it 2 months ahead, but I know how most of that hopin turns out....
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I understand the potential for some problems, wood is comin direct from the mill. I prefer not to have any, but I prefer even more to have a happy wife. You know the old adage, happy wife, happy life..... and if not.....
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We are turning my shop/man cave & garage into a house and adding on about 2,000 sq ft. she wants tall open joisted ceilings and nobody has dried RC DF anywhere's and even if they did, nope, not paying that much. This build will have the house at 3,636 sq. Next add on will add another 800 sq ft and then she'd be done. 5 bedrooms, 4 bath, 2 car.
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The 24' ceiling joists will span across the old shop area that is now 12'. I will tie these into the above ceiling to help offset any potential problems. 2' OC
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The 20' floor joists will span over the man cave kitchen area and old bathroom. This will be the new kitchen. 9'6" to the bottom of the floor joist. 2'OC
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Ceilings on both will be v grooved 6" t&g pine. Only clear coated. Beams will be stained dark with a breathable stain.
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New build will see the use of these for the upstairs ceiling joists. 20' span, 2'OC again with the 6" t&g.
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All porches will be out of the RC DF with the 6" t&g for the ceiling, with the joists being exposed.
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You are probably right, would be best to wait a year, but wife works *DanG hard and she wants a new house, so.....
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House will be built to look old and some oldness that shows up would be somewhat welcome, but of course, it could be gremlins that show up.....

[Sedgehammer]

I've read the original post and can't say I really understand it all.  Pics are worth 1000 words.  I will say this though:  It's fine to timberframe green.  I wouldn't have a problem with a floor joist that it 8x8 or 8x10 green, but such non symmetrical dimensions like 3x12 or 4x12 may crown quite a bit while drying.  That will screw up a floor or ceiling attached to it.  If you want joists like that, or even 2x material, it needs to be dry before install.  I know that Doug fir is radio frequency KD'd from some suppliers.  If it's your own wood that you're milling, I'd mill it oversize and let it air dry for a year, then put it in conditioned space for 6 months to get a lot of the movement out of it, then check the MC and see where it's at.  When you use symmetrical sticks green, and they must be boxed heart, they are more likely to dry more symmetrically.  They will check on one face primarily and have some movement, but less likely to crown/bow. Even so, if you are using timbers as floor joists, you typically want to give them time if you can to see if they do move, a year if you can.  Then you can correct for that initial movement.

I installed DF T&G 2x flooring in a loft without checking the MC back in 2016.  Well it shrank and we have some significant gaps now.  And it was nailed down, so taking it up would destroy it.  Unfortunately dimensional DF that this flooring started from is allowed to be KD down to 20% and sold as KD.  Hardwood is typically dried down to 6-8%.   So you have to beware and check the MC and make sure it's down to at least 8% before installation on any T&G.

Brad, didn't address the T&G fully from your last paragraph.
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All the T&G would be KD 5/8". We call it car siding usually. 6" wide with a V groove in the middle, plus grooved on the T&G.
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Might be going a different route with the T&G. Have access to used log road logs. Can get them squared off and cut to 3/4" up to 16'. Mixed hardwoods. Run them through the planer and rabbit them for overlap (ship lap). Pre-coat with a clear urethane and install.  

[Sedgehammer]

I've read the original post and can't say I really understand it all.  Pics are worth 1000 words.  I will say this though:  It's fine to timberframe green.  I wouldn't have a problem with a floor joist that it 8x8 or 8x10 green, but such non symmetrical dimensions like 3x12 or 4x12 may crown quite a bit while drying.  That will screw up a floor or ceiling attached to it.  If you want joists like that, or even 2x material, it needs to be dry before install.  I know that Doug fir is radio frequency KD'd from some suppliers.  If it's your own wood that you're milling, I'd mill it oversize and let it air dry for a year, then put it in conditioned space for 6 months to get a lot of the movement out of it, then check the MC and see where it's at.  When you use symmetrical sticks green, and they must be boxed heart, they are more likely to dry more symmetrically.  They will check on one face primarily and have some movement, but less likely to crown/bow. Even so, if you are using timbers as floor joists, you typically want to give them time if you can to see if they do move, a year if you can.  Then you can correct for that initial movement.

I installed DF T&G 2x flooring in a loft without checking the MC back in 2016.  Well it shrank and we have some significant gaps now.  And it was nailed down, so taking it up would destroy it.  Unfortunately dimensional DF that this flooring started from is allowed to be KD down to 20% and sold as KD.  Hardwood is typically dried down to 6-8%.   So you have to beware and check the MC and make sure it's down to at least 8% before installation on any T&G.

@Brad_bb if you could suggest what you think besides waiting, that i can do to move forward on this as best as possible. Also it seems, unless I'm misunderstanding, what you are mentioning is in conflict with what Jim is saying.

Hope you don't mind @Jim_Rogers that I added you to this discussion, but I'm about to jump in really deep and want to make the waters swimable as possible if you know what i mean.....

Dave is right FOHC beams won't check as much as boxed heart beams.
As to why they stay straight, Dave's Doug-Fir, could be the quality of the tree and the amount or not of sap wood as Mark has mentioned. It could be the type of wood. Wood is very variable, and each tree is different, depending on where it grew, on a hill side or on flat ground, for example.
My experiment log may have grown on a hill side and therefore have some tension and compression wood in it. Or the bowed timber could have more sapwood in it. 
It's hard to say, why one my 9 o'clock timber bent and the 3 o'clock timber didn't. And I've had boxed heart timbers bend. 
Jim

Jim, I'm confused or does this only pertain to beams and what Brad is saying applies to symmetrical green only? Any and all help would be most welcome.
Thanks