Replies

1. 
   West_Coast_Kurt | Jul 30, 1999 09:55am | #6

   *
   >Let's not forget the extra cost of that fancy rim they sell you. I had a chance to get free I-joists for a 12x20 addition but the rim was more than new 2x10's for the entire floor.

   >And yes they are bouncy. We got a callback on a commercial job when the file cabinets looked as if they might topple when someone walked by.

   Good Luck. Kurt

1. 
   wedge_head | Jul 30, 1999 07:10pm | #7

   *Geoff is right. As a professional firefighter who is stumbling through the construction of his own home, I an tell you that at least out here on the west coast lightweight construction is a concern anytime we get a house fire with heavy involvement. That was definitely a concern of mine when choosing my floor, but cost was still the big factor. About three times the price for I joists in my case.

1. 
   Terry_Eaton | Aug 02, 1999 06:16am | #8

   *Designed properly, engineered joists will make for a stiffer floor. A common problem is using the span tables too literally. The listingis the maximum allowable spans. Just as most builders would not try and use the minimum size allowed 2x joist to acheive a stiff floor, you should not push the limits of engineered joists. If your spans are close to the limit, eitherchoose taller joists or close up the spacing. As to cost, I've found that the market price of 2x joist material too changeable, usually up, just after I present my bid. My supplier of engineered joists keeps consistant pricing. Get used to engineered joists. They really are superior for most applications.

2. 
   Guest_ | Aug 06, 1999 04:10pm | #9

   *
   Terry, I agree with you for the most part. Until you got to the part about "closing up the spacing".

   Increasing the depth of the joists *will* make a floor stiffer. Decreasing the spacing has very little effect.

   You are definitely right in saying that it isn't a good idea to push the limits on span tables. The "spring" or "feel" of a floor isn't considered when making up span charts.

1. 
   Guest_ | Aug 07, 1999 12:40am | #10

   *I think the answer is ........ it depends on the design. For longer spans, engineereed joists are most likely the way to go. As far as bounciness (deflection) is concerned, that too is a matter of design. L/360 over a long span will give you a fair amount of movement. It may be legal but not too comfortable to walk on. Depending on the manufacturer, bridging may be required in certain applications. Your local supplier and the maufacturer are good sources of information.

1. 
   Guest_ | Aug 07, 1999 04:34am | #11

   *I think you've hit it on the design thing. I'm using 2x10 Southern Yellow Pine in my personal house. Part is a 15' span which is on 12" centers, 3/4" t&g plywood, constuction adhesive, I don't think I'll get any bounce. I'll try not to use any really badly crowned stuff, and am sure I'll have a fine floor.Study as it's gotta be, BB

1. 
   Guest_ | Aug 07, 1999 06:02am | #12

   *

   Having the luxury of being able to compare, the first 8 or 9 years in the trade, to the last 6 years I'd say the I'm now a fan of engineered wood products. I have no bounce in any floors built with EFJ's, and I never will. To keep it short, there are just to many +'s to them. One "big" one is length, I just ordered a load of 11-7/8" SP 55 40ft's and 9-1/4" SP 55 36ft's. The cost for the 11-7/8" were $2.10 pf. and the 9-1/4" were $1.66 pf.

   Once you start to work with them, you will really like them.

   Joseph FuscoView Image

1. 
   Guest_ | Aug 07, 1999 08:04am | #13

   *Dear Lew,You might not even be reading this strain any more, but I thought that I'd throw in my two cents. In all the houses that we build now, we are using floor trusses. Floor trusses have an advantage over I-joists in the way that they are connected where the rim joist would be. The best advantage is the amount of space in the webs. As was mentioned before, you don't have to worry about drilling through them for pluming, the HVAC guys can run their ducts right through the webbing, and the electricians can easily run their wire. The truss company also should supply you with a layout for the trusses which should be designed so that you miss plumbing walls, etc. They aren't the cheapest, but the money saved in labor during and after the framing stage can help make up for it.

2. 
   Guest_ | Aug 08, 1999 04:03am | #14

   *Joe - $2.10 sounds pretty high for 11 7/8" I-joists. I'm kind of curious what brand they were, and what part of the country you're in.

3. 
   Guest_ | Aug 08, 1999 04:48am | #15

   * Ron,

   The manufacture is TJI (Trus Joist) these are a series 55. Most spec a series 35 which run about $1.60 pf. for 11-7/8". I'm in NYC.

   Joseph Fusco View Image

4. 
   Guest_ | Aug 08, 1999 08:10pm | #16

   *Gentlemen,It seems that dimentional lumber for joist are going by the wayside. Wedge head suggested using doug fir, but I would have to disagree. For floor joist, I wouldn't use anything except #1 Southern Yellow Pine. They are much stronger. However, trying to find lumber long enough and straight enough is getting harder to do. And the width.....in one stack of 2x12 joist you will find boards that go from 11" wide up to 11 3/8" wide. That makes it neccessary to rip them all to one uniform size unless you want a wavy floor above.I hate, I repeat HATE those TJI joist. They are flimsy, and I have had them fall apart on me. and they do make a bouncy floor. If you have to use a non-dimentional lumber floor system, I vote for floor trusses. They are strong, they don't bounce if engineered right, and the electricians and plumbers love to run wires and pipes through them.That's what I think,Ed. Williams

5. 
   Guest_ | Aug 08, 1999 11:29pm | #17

   *Thanks for the info Joe. I never thought about it being a higher series of I-joists. The high cost just threw me. Truss Joist brand isn't used a lot in central Illinois due to their higher cost, and lack of availability. It also seems to me that Truss joist Corp. seems king of arrogant. I've had a hard time getting anything out of them several times. It's kind of ironic, in a way, though - Truss Joist spent all that money on promoting I-joists, but don't have all that big of a market share. (At least as far as I know)

6. 
   Guest_ | Aug 09, 1999 01:47am | #19

   * Ron,

   TJM is a pain-in-the-ass to deal with directly. Most times we substitute with a "like" material from another manufacturer. I have another small addition coming up and I think I'm gonna give floor trusses a try ;-}.

   Joseph Fusco View Image

3. 
   Guest_ | Aug 09, 1999 01:47am | #18

   *
   Title pretty much says it all.

   In new home construction, what is the best way to go for the joists, including the issues of initial cost, installiation time and quality of finished floor?

1. 
   Guest_ | Jul 24, 1999 03:09am | #1

   *Conventional joists are the cheapest choice, if you consider materials only. They are also the most readily available, as they are obviously stocked at lumber yards. Their primary disadvantages are that they take more labor than any other framing system, and they aren't very straight.I-joists are virtually always more expensive as far as material costs, but take a bit less labor. They are almost perfectly straight, and will probably give you the flattest floor. Some situations require time-consuming blocking, mostly in multi-story applications. They also typically require a few days of lead time to get in. They are generally easier to get plumbing and wiring in than conventional lumber. It isn't talked about much, but fire performance IS a concern with I-joists. You didn't mention wood web floor trusses, but what the heck - I'm on a roll.Floor trusses are generally the most expensive to buy, but take the least labor. Plumbing, wiring, and sometimes even ductwork can be run through the trusses. (Ductwork requires quite a bit of pre-planning, though) Trusses require the longest lead time to order - often 2 to 4 weeks. Any of the 3 can give you a good floor, if you follow written guidelines. But don't push span limits - you'll get a bouncy floor.

1. 
   Guest_ | Jul 24, 1999 05:13am | #2

   *Ron,I agree. You may have to order early, but with the way lumber is today, I can't recommend soild lumber for floor joist.Not like it used to be.Ed. Williams

1. 
   Guest_ | Jul 26, 1999 02:26am | #3

   *I have capped many a foundation for Habitat for Humanity. Some of those were done with engineered joists and some with 2x10s. We have found that the I joists can be installed much easier than the 2x10. The I joists are delivered in 30 ft lengths--enough togo from wall to wall. With the 2x10s, the layout must be offset on either side and crossover blocking and bridging must be installed. I would recommend the I joists.Eric

1. 
   wedge_head | Jul 30, 1999 08:28am | #4

   *Lew:Just went throught the same dilemma with the two story I'm building.(owner-builder) With my spans I could have used 7 1/2" TJI's, but no room for plumbing. I chose 2x10 doug fir and have no complaints. I got quality lumber from my local yard,( not H.D.) and had very few culls. 3/4 T&G OSB over 2x10's on 16" ctrs seems plenty stiff, but my longest span is 16 feet. The few floors I "test drove" with TJI's seemed bouncy to me. Hope this helps.

2. 
   Guest_ | Jul 30, 1999 09:33am | #5

   *Lew, all the above is good advice, but one drawback to I joists is their short burn time if there is a fire, talk to some local firefighters and get their opinion, this is what I have heard "over the fence". hope this helps, Geoff