From what I'm led to believe, a solid piece is stronger than a built-up one (say, with four 2 by 12's)...
Well every construction guy i talk with around here would definitely go with a built up one rather one solid piece, for the reason you gave below :
As far as I understood it from my engineer, when using separate pieces to make up a member -- when they are joined properly and intimately -- any defects in an individual piece, at a specific point, will be compensated for by the other pieces, and vice versa (isn't this one of the principals of plywood anyway?) -- thus making the member stronger than the sum of the individuals (Gestalt!).
Great definition BTW. And since all wood grain won't go in the same direction in a constructed one. it should be stiffer too.
Although I think it's very important to consider: IF the solid member has no defects, is straight and tight grained, then many advantages in 'lamina' might probably be diminished, at least somewhat...
Plus, built-up members definitely need to be made from individual pieces that are the FULL length of the finished member....
And the intimate connection between pieces is still very important -- so gluing, clamping, and screwing is crucial (it is HERE where it seems why engineering tables 'caution' with 'downrated' strengths, etc. -- there's simply no way they can guarantee if it will be done right in the field... btw, isn't this one of the problems with the Big Dig roof collapse?... the engineers relying too much on proper technique of the contractors?).
thanx,
K
orangenumerik wrote:
Well every construction guy i talk with around here would definitely go with a built up one rather one solid piece, for the reason you gave below :
Great definition BTW. And since all wood grain won't go in the same direction in a constructed one. it should be stiffer too.
The "Big Dig", from what little I read, seems to have been a caricature of the corruption/apathy in large projects we all hear about; for most of US, however, if you PERSONALLY aren't aware by now that letting "professionals" make decisions in your build (un-supervised/questioned by you) isn't TOTAL FOLLY, then I've been remiss and I apologise.
I've not messed much with glue lams, but would hope that they use exterior grade glue in ALL cases just to be sure - but before I would "ASS-U-ME" that, I'd be doing quite a bit of research... Steve
...
I've not messed much with glue lams, but would hope that they use exterior grade glue in ALL cases just to be sure - but before I would "ASS-U-ME" that, I'd be doing quite a bit of research... Steve
TomVan wrote:
...Question to all. Would you want to use a Glue lam on an exterior wall?
Would there be problems with potential moisture and loss of strength?
They do use glulams in exterior things, especially wooden bridges (probably mostly in restorations of small local bridges in bucolic communities that wanna preserve their character, or in foot/bike bridges)...
For exterior uses, resorcinol/formaldeyde adhesive types seem to be the king...
But as Steve said, one must verify potential exterior use for the glulam to make sure it is 'rated' for it -- not just the glue, but also if the wood is treated or resistant to moisture/rot.
http://www.agriculture.purdue.edu/fnr/E ... fnr154.pdf
...It is also hinted at in this article of why a field-made glue joint is usually inferior to special factory-made glue joints...
Curiously, about the Big Dig, I knew some people who used to brag about how many hours they worked and how much money they got from working on the project...
Now, they don't say too much...
And probably put it 'lower' on the resume or curriculum vitae, or perhaps 'diquise' it by using a firm's name instead of the project name.
K
Well it was a long weekend and the trusses are up and 98% of the plywood is on. I will post tomorrow new pics. The roof work is hard on the knees and back a little tired from it all. I need to purchase 3 more sheets of plywood and it is finished
Steve....Knightfly
I have some concerns and questions about hanging the sheet rock ceiling. Right now it would be the best time in my opinion. wide open and nothing in the way. Should it, could it, be done correctly? A money saving opportunity here. But Can I do it properley.
Can I ask of you and make a proposition (Steve/God in the NW) I will pay for your travels and hotel room plus food/beer/spirits for a look see and an explanation of how to do it plus all the other questions I have post framing. You need to get out and have some fun too. 8)
After reading Rods book it made more sense than ever to make sure I do this correctly. I have it figured out in my head but would love to have an expert on site to make sure I understand what I have planned. Decoupling and all........
You also need to get to Portland just for fun anyway. Let me know
Thanks
Tom
Ok here are the pics I promised. After laying the trusses upside down and in the middle of the building we noticed the exterior wall had buldged out a couple of inches so we set up a wench and pulled it back plum. Trusses took 4 guys about 4 hours. Then we placed about ten sheets of plywood before we called it a day. I placed the rest on sunday by myself. I think I scared everyone off.
I am short 3 pieces and will get those on this week.
Looks great!! 8)
How much mass are you going to put on that outer leaf? :roll:
I'll bet that big garage-door-like opening is coming in really handy during construction. Will you be closing that up last?
I'd definitely be skeeeeered putting that plywood on those trusses! :oops: Especially by myself! :shock: How the heck did you manage to carry the sheets up there? :roll:
Also, you're probably not permitted to hang drywall yet until all the framing, electrical, and mechanical is signed off.
--Keith :mrgreen:
Tom, I may be able to come up (between alligators :=) but it's better to drywall when it's actually DRY - meaning, building enclosed, heat/dehumidifier running a while, wallboard stacks "normalized" to the drier conditions...
Are your scissor trusses spec'd to heavier dead loads than normal so you can double your outer sheathing and hang the rock on RSIC's/channel inside, or are you planning to VENT the outer cavity and put TWO separate leaves inside for your m-a-m construction, or?? Sorry, don't have time to look for sketches ATM, gotta do about 6 day's configuration stuff TODAY if possible, looks like I'm "poised for exhaustion" in this new industrial video thing if I can hang on for the ride.
Or, is your inner drywall on trusses gonna be the outer leaf, and then separate INNER ceilings on each room, or partly one way and partly the other (like live room large with truss being the inner leaf) -
Anyway, hopefully I can take a day when it'll be most useful to you - But I'd really consider doing your drywall AFTER the place is enclosed/heated/dehumidified a bit... Steve
Steve,
They are spec'd for three layers of 1/2" rock. My plan was to put one 1/2" up against the roof plywood and then two layers on RSIC's in the live room only. And then all the other rooms will have seperate ceilings. But if I could hang the entire thing now I would do it all like the live room.
Makes sense about the humidity at this time of year.
As soon as you come up with an idea when you "might" be able to come on down just say the word. If not its all OK too. I like the visuals onsite better than the blue prints in hand
Keith,
Just planning ahead as much as possible. Need to get framing and electrical in the walls first. Its so hard to miss the opportunity to hang the entire ceiling before getting all those darn walls in the way. You can always get a partial inspection for covering if needed.
As far as taking 1/2' plywood up a ladder that I had positioned on the back side where it was less than a 45 degree walk up the ladder wasn't so bad. Just slung it orangutang style over my shoulder. A sheet weighs probably 30-40#. What kills you is the walking/kneeling on a roof all day. My thighs and calves are tender today.
And my outer leaf will be two layers of 1/2" plus the 1/2" t-111.
I sat on the deck last night looking at my accomplishments for the weekend and started trying to come up with ways to manage the construction faster and efficiently. One of the big ones was when to close in the garage door opening. It would be easier to get a couple stacks of sheet rock in, but the CR will have walls blocking passage. So Still thinking on when to close and when not to.
There were a couple times I thought of Kathys Barn conversion and then wondering if anyone was watching me just stare at my work. :D
Tom
Steve the man,
I was just reading over the loads for my trusses and the BCDL is 10psf. The TCLL is 25 psf. I already emailed the manf. but have had no return email. Can I get away with two layers of 1/2" plywood on top so I do not have to hang sheet rock on the inside bottom. And only insulation on the interior before hanging RSCI and two layers of 1/2" rock. Or can I put multiple layers of felt and get the same results? I know I am stretching but always looking for the easy way out. Obviously anyway to get away with cutting 22" pieces of sheet rock to fit between the roof joists. And putting them in place. I have to apologize but I do not know how much sheet rock weighs or I could figure this out possibly on my own. :roll:
Thanks
Tom
Not sure what the BBS software will do to this, it's a word file I built for stuff like this -
Weight of Standard Drywall panels -
Regular Drywall Panels. To convert from PSF to kG/M^2 multiply PSF x 4.89
Panel Size /Weight /Lbs/SqFt /PCF /kG/M^3
4' x 8' x 3/8" = /45 lbs. /1.406 /42 /675
4' x 10' x 3/8" = /56 lbs. /1.406 /42 /675
4' x 12' x 3/8" = /67 lbs. /1.406 /42 /675
4' x 8' x 1/2" = /54 lbs. /1.6875 /42 /675
4' x 10' x 1/2" = /68 lbs. /1.6875 /42 /675
4' x 12' x 1/2" = /82 lbs. /1.6875 /42 /675
4' x 8' x 5/8" = /74 lbs. /2.3125 /42 /675
4' x 10' x 5/8" = /92 lbs. /2.3125 /42 /675
4' x 12' x 5/8" = /110 lbs. /2.3125 /42 /675
4' x 8' x 3/4" = /90 lbs. /2.81 /42 /675
Firecode Core Panels
4' x 8' x 5/8" = /70 lbs. /2.1875 /39.73 /638.5
4' x 10' x 5/8" = /88 lbs. /2.1875 /39.73 /638.5
4' x 12' x 5/8" = /105 lbs. /2.1875 /39.73 /638.5
Medium Density Hardboard – 43-60 PCF typical density, or 690-960 kG/m^3
To convert lb/cu ft into kG/m^3, multiply by 16.04. To convert the other way, divide by 16.04.
Concrete weights approx. 3600 lbs/cu yd when cured, about 3900 pounds wet.
133 lbs/cu ft, or 2133 kG/M^3 -
MDF - approx. 68 pounds per ½” 4x8 sheet or 2.125 PSF, 53 PCF, 850 kG/M^3
Glass = approx. 3.8 times weight per unit thickness of sheet rock - roughly 161 lbs for 4x8 sheet of 3/8” glass.
The surface density of ¼” plywood is 0.74 lb/sq ft, or 23.68 pounds per 4’x8’ sheet.
The surface density of 3/8” plywood is 1.11 lb/sq ft, or 35.5 pounds per 4’x8’ sheet.
The surface density of ½” plywood is 1.48 lb/sq ft, or 47.36 pounds per 4’x8’ sheet.
The surface density of 5/8” plywood is 1.85 lb/sq ft, or 59.18 pounds per 4’x8’ sheet.
The surface density of ¾” plywood is 2.22 lb/sq ft, 71.04 pounds per 4’x8’ sheet, 35.5 PCF, 562.5 kG/M^3
A dry 8’ 2x4 weighs about 10 pounds, 2x6 about 15.7 pounds; density about 4.28 PSF for 2x lumber. This puts 2x lumber at roughly the same density as a layer of 5/8 and a layer of ½” drywall. 2x10 about 28 pounds per 8' length, or 3.5 lbs/lin.ft. –
2x10 framing on 24" centers adds approx. 2 lbs PSF dead load. 2x10 on 16" centers adds 2.7 PSF to dead load.
2x8 framing on 24" centers adds approx. 1.6 lbs PSF dead load. 2x8 on 16" centers adds 2.1 PSF to dead load.
2x6 framing on 24" centers adds approx. 1.2 lbs PSF dead load. 2x6 on 16" centers adds 1.6 PSF to dead load.
Celotex has an average density of 16.8 PCF, or about 39% as dense as gypsum wallboard.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
I was just going to ask you about this very thing this morning - only thing I'm still trying to figure out is VENTILATION between your outer roof and the ceiling if you use these as your two leaves - it's NOT good to seal up such a cavity without some sort of way to vent it, and if you vent it it'll hurt isolation.
If you're not already too far along, let me think about this a bit (and if Rod want's to chime in with a "magic bullet", even better)
I agree, if you're gonna use those two leaves for iso it'd be much easier to double sheath than to do inserts; I came up with the insert idea a few years ago in response to RETRO construction, not NEW... Steve
Perhaps the attic could be mechanically ventillated with lined ducting/silencers, in such a way that would minimize penetrations and ensure otherwise air-tightness...? :roll: Such an attic coould possibly be accessible, as long as the access door were sealed really well...
WOW that was a wealth of info. I agree with Ro sticky that one up Thank you thank you Steve
OK so it looks like my top and bottom loads are fine. Should have plenty of elbow room. And the venting was also my next question.
I installed the bird blocks that came with the trusses. Half vented and the other half solid. I wanted them installed for the purpose of resale down the road. Knowing I would have to block them in some form or fashion for the studio. Standard green rock ?. As far as an attic vent I could set up a circulator in the bathroom with insulated flex hose. The ceiling in the bathroom will or can be lower than the live room I could build a access box to get to it from inside the bathroom.
Keith the scissor trusses do not allow much room for a crawl space in the rafters. But your thought got me to this.
I installed a gable fan this summer in house because it was poorly vented. No vents in the gables at all. After i installed the fan it changed the temperature inside drastically. The instructions that came with the fan showed fresh air being pulled from the bird blocks and or roof vents. It has a thermostat on it so it automatically comes on when it gets up to 90 degrees in the attic space
Let me know guys
Steve,
Been thinking. Regardless of how you vent it still needs to be.
Some studios have AC with fresh air. Some of the drawings I have seen are insulated boxes with bends to slow down the sound. I assume
Would not an insulated flex pipe be of the same idea?
I had planned on hanging baffles throughout the entire roof line. Will this be a help? and if I allow fresh air in through a few bird blocks could I just build an insulated intake box with bends in it?
Would 1/2' OSB for my sheathing be more dense than plywood?
BTW I am not to far to have to tear anything down yet. "YET"
That was my main concern before I started all this.
I hate going backwards. Do it right the first time
So, are you saying you'll have a three leaf system -- two ceilings and a roof, yet the attic will be ventilated?
If so, that should be fine -- it's what I'm doing with my project and what I think many people do. The larger the attic and the more generous the venting, the less of a third leaf effect is experienced. I think. Take with grain of salt. I'm not an expert, I only pretend to be one once in a while! :lol:
Hey Tom -- you sure have a lot of construction going on for a guy who hasn't finished his plans! :shock: (That's a hint: slow down, my friend!! ;-))
--Keith :mrgreen:
So, are you saying you'll have a three leaf system -- two ceilings and a roof, yet the attic will be ventilated
No just a two leaf.
You have to remember even if I did have a three leaf the attic space would still be very narrow. You also have to remember I have a new build and no limitations as far as existing conditions to work around, . . What I had forgotten was ventilation in the attic space. If you dont have it your comp roof won't last as long as it should. The tiles will overheat and become brittle faster than usual. I realized all this after getting the trusses on last weekend.
And as far as slowing down NO Way. Everything is a build in progress and can change with new concerns and or changes. Initially I was going to cut 22" sheet rock and hang it on the bottom of the roof. Yuck Even lay out once I see the wall configuration on the floor might even change. Most of what I do in my biz Are called RFI's, Request for information to the architect asking what they mean or how to proceed with their drawings
If I had it all planned out I would be an architect that knew what he was doing. :P Haven't met one so far
If I'm interpreting what you're doing correctly... Rather than put drywall on the plywood between top chords, why not just run more plywood on the roof?
Yet, do you plan to use RC or RSIC clips to decouple your inner leaf ceiling from your trusses?
Do you have any cutaway view drawings of your ceiling detail and wall detail?
TomVan wrote:
And as far as slowing down NO Way. Everything is a build in progress and can change with new concerns and or changes . . .
I have to be honest -- that doesn't seem to be a winning plan... :roll: ...I understand the motivation to keep moving, believe me I do. But some changes after the fact become very cost prohibitive, such that if you have the opportunity to plan your steps carefully, it's really in your best interest in the long run (and the short run) to do so.
Even then, there will be tweaks along the way, for sure. But I would think the goal would be to keep those tweaks to a bare minimum... :roll:
I'm not trying to be a downer -- I really want to see you succeed in your project! :)
--Keith :mrgreen:
Weights/densities added to REFERENCE link, 10-12-06 (near the top)
Keith has some meanderings about splitter-silencers on his thread that could help, as far as venting I'd use them in/out of the "plenum" created between inner and outer chords of the scissor trusses, put your vapor barrier on the OUTER leaf (between existing and next layer of plywood), then consider your "plenum" as being "conditioned" space, and vent your plenum to the INSIDE thru the splitter-silencer.
A power vent fan installed in one of these ducts would then circulate INSIDE CONDITIONED air thru the "plenum"/attic area, which, in combination with a dehumidifer, would keep everything DRY.
I'm NOT even close to being an HVAC or silencer design guy, maybe Rod has some "WOW" (Words Of Wisdom) here - my thoughts on this are a total hermetic seal at the OUTER leaf of the building (bugs, etc) and a dry interior, since I wouldn't consider building anything resembling a studio in the Northwest that did NOT have dehumidification built in - there's only about 2 months of the year when the RH is low enough for proper wooden instrument storage :roll:
Multi-leaf - unless you need 100 dB isolation to the outside, this envelope will be adequate. Inner rooms only then need isolation BETWEEN each other, which has nothing to do with the SHELL.
If you then want a drum room that's well-isolated from the rest of things (for easier mic setup without bleed), START OVER with the m-a-m principle (m-a-m between drums and everything else) - if your slab isn't heavy enough for a second, floated slab, then a heavy wood floor over RIM's will still get you a LOT of help (except maybe for kick drum), along with double framed double 5/8 gyp walls and a decent air gap... Steve
Steve,
Perfect. Sounds great. Looks like I will be able to finish the outside shell this weekend. Just ordered a bundle of OSB since the price is about half of the plywood. And the density is slightly greater. The lumber yard said to make sure and cover asap with felt since OSB swells rather than gets wet like plywood. And it looks like its going to rain on sunday Woo hoo
found this:
PROPERTY ------------ PLYWOOD ----------------- OSB
Density ---------- 500 (DFP), 450 (CSP) ---------------- 640
(kg/m³)
Nail Holding ----------------- 15----------------------------- 13
(N/mm)
Thickness Swell ----------------7----------------------------10-20
(%)
And just did some reading on the web about splitter-silencers. Makes sense to me and also looks like a great way to exchange air in the studio too. In reading Rods book about portable heat pumps
(which I already have 2) he commented that they have a hard time bringing in enough fresh air fast enough. So it looks like the bathroom is going to be a little smaller. I guess you only need enough room to s it :shock:
Thanks again Steve for all your help and sleepless nights worrying about us