Old house (fire job) Everything is grossly undersized anyway. My question is about a second floor the room is 16×20 (unsupported) the floor below must remain wide open. I’d prefer to stay with framing members 8″ tall or less (ex. 2×8). What method do you suggest. I’ve been told everything from “just use 2×8’s” which can’t span 16′ (can they?) or Use I-joists (will an 8″ tall I joist span 16′?) to Use steel (NO)
What would you do.
Can’t I go 1 day without spilling my coffee?
From building boxes and fitting face frames to installing doors and drawers, these techniques could be used for lots of cabinet projects.
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Replies
I don't think you can buy a 2x8 I-Joist
UseLVLs
Excellence is its own reward!
Lunicy,
Another option would be to use 2x8's and double them up every 16 inches. Done that way it would be strong enough unless they plan to put a grand piano or a hot tub up there.
Mark
You can get 8" TJI's with a 3" flange. I am not sure of the span, maybe on 12" centers. Call your lumber yard, they'll have the info. My only thought on LVL's is the horendous cost.
Anything that shllow and that long isn't going to work well. You might be able to use 2X8s about 6" O.C. and get them to look good on paper. But they're going to deflect a lot and bounce like hell.
Money can't buy happiness. But it sure makes misery easier to live with.
Lunicy, span of joists for 2x8 from my chart as follows:
spacing 40# live load
plaster ceiling no plaster
12"oc 14'1" 17'5"
16"oc 12'11" 15'3"
24"oc 11'4" 12'6"
So the answer to using 2x8's is no (assuming plaster ceilings in old house) but not sure of alternative if you want to stay within 8" height. 2x10's 16" oc will span 16'3" 40#LL and plaster ceiling. I'd use 2x10"s or as suggested previously call your local yard for help. Local yard doesn't mean HD!
Harry's Homeworks
Rhode Island
Are you sure you're not using a chart for ceiling joists or something? What species and grade is that for?
My span book shows a max of 14' 5" with #1 SYP at 12" O.C. L/360. Nostalgia isn't what it used to be.
Nope, It's definately a floor joist chart. Note on my chart includes weight of joist and double flooring. Maybe that's why yours is 14'5" and mine shows 14'1" with plaster ceiling below. Make sense or am I missing something?Harry's Homeworks
Rhode Island
You didn't mention what species the span chart you used is.
Also - How old is it? They changed the lumber design values in 1991/92.Men are Like bike helmetsThey're good in emergencies but usually just look silly.
Hey you got the answer!! My book with the chart was copyright 1973. Time for a new book, although I don't do much framing anymore. Last time I used the span chart was on a 2nd floor addition back in '81. Too old for that heavy stuff anymore. Thanks for the response.Harry's Homeworks
Rhode Island
It's already been pointed out that your 2x8's are a no-go at your span but you didn't specify why you want to stay at 8" or less. Is there a ceiling height issue or are you just trying to save a few of those little green fun tickets with president's pictures on them? You also didn't specify what your aversion to steel is. If the 8" thing is a real priority it can be done but it will cost more than up-sizing your framing members. If the steel issue is about wanting to nail into wood you might be able to build wood flanged/ metal tube webbed joists that will meet your load requirements but I would highly recommend the services of a competent engineer for such an undertaking.
On the design side- you said this is an old house so the style probably wouldn't fit but it bears mentioning that this joist style can look ever-so-cool if you build them right and leave them exposed.
Any way you slice it, it's kind of like building a high powered engine. You can get a little one to perform like a big one but you are going to have to get used to the screaming sound and it is probably going to cost you out the tailpipe end of you anatomy!
Kevin Halliburton (still trying to come up with a cool tag line)
Ceiling height is the issue. And as for the steel, I priced it and btween the extra time and money involved in that, it was a no-go w/ the HO
Can't I go 1 day without spilling my coffee?
I don't know what your situation looks like so I'm just tossing out a few ideas here. They are free and worth every cent!
What is the ceiling height you are concerned about? There are ways to increase the "perceived" height of ceilings with color, light, vertical wall elements, etc. if it's not going to create a head bumping situation.
Can you lower the ceiling height of the first floor or raise the ceiling height of the second floor?
If the roof is pitched and the 2nd floor ceiling joists rest on the top wall plate, could you attach them to the rafters higher up and leave a chamfered edge around the ceiling perimeter where it transitions to the wall. (probably another load issue worth consulting an engineer about)
How about building scissor trusses onto the bottom of the existing roof joists and vaulting the upstairs ceiling.
Maybe you can leave the joists exposed on the second floor ceiling and cover them with tongue and groove from above to add a sense of height.
If you can, would adding a dormer help? Sheds give the most usable space for the $$$.
I understand that the floor space below has to remain open so supporting a load from below is prohibited but can you figure out a way to SUSPEND the second floor at mid span from above? You will definitely be back to using some steel here but not near as much as using it for the entire floor. (once again- hello Mr. Engineer)
With the exception of the first suggestion I probably haven't offer anything that meets your HO's budget constraints if he is concerned about the steel price but I'm really just trying to get us all thinking. It's easy to get tunnel vision about a problem. Builders are notorious for their ingenuity. Maybe there is an "out of the box" solution staring you right in the face.
Good Luck,
Kevin Halliburton- (I gotta get one of those cool tag lines)
Kevin Halliburton,
One of Dick Cheny's Big Oil Buddies!
Spelled different, but what the hell?
Joe,
Check it again, my last name is spelled EXACTLY like the Halliburton Oil Company... let's just leave it at that.
Kevin Halliburton
Try this: (DIY LVL)
1. Prop up your 2x8 to create apr. 1/2" camber (crown)
2. Rip 3/4" SYP plywood to size, laminate both sides of 2x8 using PL2000 &screws-
Where do you get plywood this long to laminate to the joist?.
Excellence is its own reward!
Plywood lamination of joists is accomplished by ripping sheets and butting them end to end. Stagger the breaks on either side.Baseboard been VERRRY good to me
Without a continuous piece to laminate on either side, I doubt you can gain much more than enough to off set the added weight you are putting on it..
Excellence is its own reward!
I could be spittin' into the wind, since I never have actually done this, but then neither has any other responder! So the ceiling has been removed and we can see the joists and subfloor above. I'm assuming the ceiling joists can't be jacked up a little in the middle 'cause there's probably not enough support under the first floor. Too bad, that sure would help. Any way, adhesive the 2nd fl joists to the 2nd fl subfloor. Then adhesive and fasten staggered ply rips on either side of the joists... then adhesive the ceiling material to the bottom of the joists. I've sistered some sketchy joists together that way , nothing 16' across, admitedly, but I have made box beams out of 8' plywood that spanned 24' and held 2nd floor living spaces over garages. Mock a couple up and see if you bounce or break?!? EliphIno!
Lunicy,
Is this house balloon framed?
If so, would it be a problem to use 2x10's and keep the tops even with the rest of the 2x8's and loose 2" on the first floor ceiling?
I do alot of fire jobs and we did one like I just described about a year ago and the second floor bedroom was the case but undernearth on the first floor was the dining room and it didn't matter to loose 2" in the ceiling.
Just a thought.
Joe Carola
Suggest that you read the article in FHB #150 (Nov. '02) on engineered lumber.