Replies

1. 
   GACC_DAllas | Mar 05, 2001 05:50am | #1

   *
   I'm sorry Mike,

   Nothing but steel will span 30' for a live load floor. You better call the engineer too.

   I wish you homeowners wouldn't fool around with this structural stuff. Get an architect to design the structure. Then you can build it yourself if you want.

   Ed. Williams

1. 
   Mike_Niggel | Mar 05, 2001 05:56am | #2

   *Actually it has been engineered by an architect. I'm just trying to find someone who has experience with this type of floor and who has actually walked on a few.

1. 
   GACC_DAllas | Mar 05, 2001 09:40am | #3

   *Mike,If it's been engineered then ask the engineer what the tolerance of deflextion might be. Personally, I don't like those "I" joist (TJI). I've seen too many of them fall apart. I sure wouldn't span one 30' with or without an engineers stamp. I'd have to go with a truss joist hung off a webbed steel I-beam if you want a more solid floor. And I've seen those bounce. You want a real solid floor, then you can use poured concrete over corrigated metal. Now that's soild. You can park a car up there. But it is expensive.If your engineer is comfortable with the spans and will sign off on it with TJI's then I'm sure it will be fine. It will bounce some........I guess it will come down to "How much bounce are you comfortable with"? What may seem a little to me may seem like a lot to you.I'd ask the engineer if he's done any similar floors and see if the homeowner of that house has any complaints or will let you come walk on his floor.I think I may stay away from the engineering questions from now on. Good luck,Ed. Williams

1. 
   Tony_Ferrito | Mar 05, 2001 02:50pm | #4

   *Mike, Here's a neat trick my boss in Maine showed me.Frame up your floor with a mid span beam supported with some temporary posts. After the rafters are in but before you sheath the roof bolt some short collar ties about 1' down from the bottom of the ridge, Do this on all of the two adjacent sets of rafters that are above where your posts would be under the beam in the floor. Now put a 2' length of 4x4 on top of the 4 "collar ties" . Drill a hole in the 4x4 and hang the beam from the ridge with some 3/4' threaded rod. Use three nuts on each end and big thick washers to keep the wood from crushing. Your roof will still need to be self supporting as always. If you don't mind a couple of "tension posts" in your upstairs, this is good way to get rid of posts down stairs. I want to re-emphasize proper roof framing because if there is no resistance to spreading than the ridge will have no strength. Hope this is some help. Tony 'The Closet Engineer' Ferrito

1. 
   Rick_A. | Mar 05, 2001 04:35pm | #5

   *Mike,Bring your plans to a truss manufacturer and see what they can do for you.I've spanned a few garages with "attic trusses" which were designed for a 40 lb. live load and there was very little bounce.They go up quickly compared to setting floor joists then rafters. And my guess is that the trusses would cost about the same or less than "I" joists and rafter stock.Rick Arnold

2. 
   Mike_Willms | Mar 06, 2001 05:15am | #6

   *If you thought you needed an engineer before, you'll REALLY need one if you use Tony's idea. At least I would. The attic truss idea seems like a good way to go. I've used open-web floor trusses on a 28' clearspan, and it was fairly solid. Can't remember the size, think they were 18" or 20" deep. Plus you can bury all your mechanical inside. Floor trusses, man, way of the future! (lol)

3. 
   Tim_Kline | Mar 06, 2001 06:49am | #7

   *b WBA At Your ServiceEd, Where have you seen I joists fall apart ? Was this due to weather exposure ? Mishandling ? Manufacturing flaws ?Thanks

4. 
   Allyson_Stiles | Mar 06, 2001 07:22am | #8

   *If they fell apart, as long as they were installed correctly, they are guaranteed. They've been around since 1970 and I,ve never heard of one correctly installed failure. Whenever they bring bearing points from above to a beam or wall, they need squash blocks on both sides. And if you don't use the rim strand that you're supposed to use for rim joist, you need squash blocks there also. I'd like to know exactly how they failed.Billy

5. 
   d_j_k | Mar 07, 2001 08:04pm | #9

   *Rick is right on...keep it simple............you have to put on a roof anyway so,kill two birds with one stone and use Attic russes. Gives you a roof and a floor in your 1/2 second floor. Much faster as well.Wouldn't be surprised if it is the lowest cost solution as well.

6. 
   GACC_DAllas | Mar 08, 2001 02:57am | #10

   *Tim,I've seen the 2x top and bottom rail disconnect from the OSB webbing. I guess they just use some kind of adhesive to hold them together. I've seen it more than a few times. It may be weather related. I wouldn't leave them exposed to the rain any longer than I had to. Unless they are one connected unit, I don't think the manufacturer would stand behind the engineering. The warranty is of little consolation to me. After the fact, it's a remodel.........not a replacement.Ed. Williams

7. 
   Ron_Rosa | Mar 08, 2001 05:01am | #11

   *Wow TJI' I fall apart and hanging the floor! Break down and put the post in, with one good beam you could support it one time right in the middle , come on "YOU CAN DO IT". Just think, when the wife gives you a hard time you have some where to handcuff her to . Good Luck

8. 
   Boss_Hog | Mar 08, 2001 12:29pm | #12

   *We regularly do wood webbed floor trusses up to 32' clear spans, so a 30' clear span is no problem. I would suggest nothing less than 24" deep in that situation. You will also need to install 2X6 strongbacks to control vibration. Mike, you don't mention what depth of I-joists were proposed by your architect. If they tell you "This will work, but you i haveto out them 12" O.C." That generally means they've called out something that's too shallow and will bounce like hell. Architects seem to be good at that for some reason. Attic trusses also sound like a good idea, depending onthe roof pitch and room size you want. They're expensive, but once you set them most everything is already framed. They also allow dormers to be added in easily to allow for more space.

9. 
   davidmason | Mar 08, 2001 07:35pm | #13

   *Just framed a place with 27' clear span. We used 16"TJI's, 16" o.c., no flex at all on that floor. Dave.

2. 
   Mike_Niggel | Mar 08, 2001 07:35pm | #14

   *
   I am planning to build a 1 1/2 story garage workshop, preferrably with a clearspan 2nd floor. It is 30 ft wide. Deep I-joists will span this, but I am concerned about the floor having too much bounce. Just wondering if anybody has experience with this type of floor.