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Any opinions on floor joist types for a second floor?
Positive or negative comments appreciated.
The span across the attached garage is too great for regular dimensional lumber, so the choices are :
1) Laminate beam
2) open-web truss(?) made of 2×4
3) I-beam type wood (TJI ?)
The open-web appeals to me for ease of running wires and plumbing. What’s the relative cost for each of these?
TIA
Phil
Engineered materials and vacuum-press laminations prevent warping and keep a tall, flush-panel door from being excessively heavy.
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Replies
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Steel Beam
*Consider the depth of floor trusses and how it may effect the height of the garage compared to the house and room for stairwells. Floor trusses are o.k. if the depth doesen't come into play. They are often cheaper than eng. wood beams or steel girders and require less labor.
*If the floor joists are used in the garage only, two thoughts come to mind. since they are usually deeper, they can be dropped into the garage, using a top chord bearing member. Since they are open, the plenum that is created will be much easier to heat, thus preventing the possibioities of freeze up.My vot goes to open web design, because I had dropping a false ceiling, simply to prevent freezing.Watch your firestopoing, and draftstopping carefully!It would be very helpful to include basic dimensions if you want meaningful positive and negative answers. Size affects answers for many different reasons!To illustrate, I once had to install 24', 2x12's, 12"o.c., doubled every one! This arangement saved the builder a few bucks, and cost him a few hundred for labor!Penny wise and dollar foolish!Blue
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Blue & kcoyner,
Thanks for replying. The attached garage section is just shy of 23 feet wide and 28 feet deep (6 feet is utility area). The entrance is on the side of the house. Also on that side of the house is an 18' by 28' living area. The second floor addition would span the whole area. So joists would be needed to span the 23' and the 18' sections.
How deep would a truss be to span the 23'? Is there someplace online that I could find out the span ratings of truss joists?
TIA
Phil
*Philly,My truss chart shows the following would work for a L/480 floor:14" deep @ 12"oc, 16" deep @ 16"oc, 18" deep @ 19.2" oc or 24" ocHere in central NC the trusses run about $2.50 per linear foot
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Brian and Philly -
DON"T go with the 14" deep trusses !!! They will bounce like hell !! Reducing the spacing doesn't make your floor stiffer.
I do think floor trusses are a good choice, but they need to be 18" deep or so. They might have to be deeper if you're framing a 1 1/2 story instead of a true 2 story - you might have some bearing walls in the middle of the span, and the trusses need to be designed for that.
Blue also makes a good point, that they can be dropped down inside the walls. This will work well if you have to match other types of framing on the 2nd floor of your house. For example - If you use 2X10s on your house, and 18" floor trusses over the garage, You put a 9 1/4" mid chord bearing on the floor trusses. This drops 8 3/4" down into the garage.
Brian's estimate of $2.50 per foot sounds about right for Illinois. The mid chord bearing might run a bit more, however.
*Steel's a kiss job, as this topic proves. If anybodies head scratchin time is worth money this job could have been done twice now and as far as money, or bounce, or lost space, or firestops....yak, yak etc.Carpenters avoid steel....the next generation won't, cause have you seen the steel cutting blades just now hitting the ads everywhere?...And nail guns that work on steel and concrete!@@J
*Why can't you span the 18' section?Blue
*go with two 11 1/2 " LVLs. Fast..easy and cheap
*
Blue
18' is not a problem, the 23' section is where non-standard dimensional lumber was specified.
I like the idea of truss for ease of running wire and plumbing. But opinions stated that it will bounce.
Phil
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Phil,
Why are you allergic to a steel beam?/?
J
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Ah-choooo!
Steel is HEA-VY. And not easily bored thru for running wires and plumbing. Also, hard to nail subflooring to it w/o adding nailers.
Just too much extra ($$$$) attentions needed.
Phil
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I thought so until I used one in a large garage two years ago...Fell in love with it....
J
*I thought so until I used a steel beam in a large garage two years ago...Fell in love with it....Not as much trouble as running up this post to a few weeks chat that's for sure.J
*Steel may not cost as much as you think... sometimes less than LVL.
*
I would consider using steel as a HEADER for a double-wide garage door. But in this scenario I would need 22 pieces to span the 23 feet width of the 23'x28' garage area. [ 28 feet = 336 inches. Divide by 16" on center. Then add one. 22 joists]
Yes, a drawn out thread, but it is civil and everyone is who they say they are.
Or not? :-)
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philly, erey one is confusd here! they think you are asking about a a garage header , I think.
You still havent clarified why you can't change the direction of the span, and span the 18' way. It would probably need a girder, but the joist decision would be much easier.
Blue
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Blue, Resurecting a dead thread.
Re-read post #4, #7.1 and #7.1.1.1.2.1
|-----------28 feet - wide---------------------|
2 car garage
28 x 23
|-----------------------------------------------|
living room
28 x 18
|------------------------------------------------|
I hope this gives you a better idea of what I was trying to convey.
Phil
*
Any opinions on floor joist types for a second floor?
Positive or negative comments appreciated.
The span across the attached garage is too great for regular dimensional lumber, so the choices are :
1) Laminate beam
2) open-web truss(?) made of 2x4
3) I-beam type wood (TJI ?)
The open-web appeals to me for ease of running wires and plumbing. What's the relative cost for each of these?
TIA
Phil