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TJI’s and HVAC question

| Posted in General Discussion on June 12, 1999 07:32am

*
Help, please, from folks who have used TJI’s in floors. My builder has never used (and I suspect he is reluctant to start using). He says the trunk for the HVAC ducts would have to go under the TJI’s, and that it has to go down the center of the basement. This would make the basement ceiling very low unless we take the foundation blocks up to 10′. Is he telling me the truth or justifying his wanting to use dimentional lumber?

He also expressed concern over having two stories on top of the TJI’s; he says that they would not support the weight. What say you?

For general info, the house is a 30’x38′ chalet
with a daylight basement and a 12 and 12 roof. The second story in question is a loft with a master BR suite.

Is he giving me the run-around? I suspect he might be because he “suggested” to my husband that he not let me watch Bob, Norm, JoJo, et al.
I’m irked.

Many thanks for taking time to respond to a woman in distress.

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Replies

  1. Guest_ | May 29, 1999 11:55pm | #1

    *
    Hi Kay

    Find another builder.

    You have more options with TJIs than conventional lumber. When properly done as per manufacturer's recommendations, they will handle any load in residential construction.

    Ductwork that has to go across the joist is a problem no matter the lumber used. With proper planning, you can hide most ductwork into the joists.

    Have your local TJI rep. help with the design of your layout and discuss the ductwork problems with him or her and more often than not, a solution will be found.

    Don't accept excuses for reasons things can't be done.

    Good luck

    Gabe

    1. Guest_ | May 30, 1999 02:25am | #2

      *Gabe is right, lose him. My first guess is he bid the job withut tji & now is not wanting to make up the difference. He is probaly also afraid of something new ( to him). If he missed the tji ( no proof, just my hunch) what else did he miss?

  2. Eric_H | May 30, 1999 06:23am | #3

    *
    I am building a 4k+ sq ft Georgian/Greek Revival Colonial with all TJIs and with full stairs to the attic/3d floor, which we intend for future living space, should the need arise. I have strived for superior materials and techniques in this construction, I have an extensive HVAC installation (employing 2 a/c units) plus separate hydronic heating, all of which involves working around and through the TJIs. No one has raised such an issue with the TJIs. If your builder will bs you about this issue at the outset, imagine the bs you'll be hearing later on. The worst thing that reading up on (and watching shows about) good home construction will do to you is invite an honest builder to set you straight, if you are mistaken in your observations. Anyone who suggests you curtail your education doesn't deserve your cash. Good luck.

  3. Guest_ | May 30, 1999 07:12am | #4

    *
    Kay, I would have to agree with the other guys, this guy sounds like trouble looking for a place to happen. I have used TJI's several times and really enjoy using them. They will come with a sheet informing you what size holes you can cut to get things through them, usually plumbing and electrical chases. Most HVAC main ducts are suspended beneath the joists(wether they are 2x lumber or TJI's) and the supplies and return airs are run inside/paralell, with the joist. I haven't seen a tji cut for hvac ducts and would'nt recomend that. Your supplier should figure out load concerns and send you a layout with your materials. I wish you luck with your project. Glenn

    1. Guest_ | May 30, 1999 08:03am | #5

      *Kay: I agree with Gabe & the other posts. TJI's perform very well. Find another builder. Even if you have to wait a little while. If he feel this way about TJI's it makes one wonder what else he will have a problem with.Good luck with your project. Ron

  4. Patrick | May 30, 1999 07:21pm | #6

    *
    I, like most builders, was skeptical about TJI's when I first used them 8 years ago. I probably would have argued against them too, but I was sunbcontracting the carpentry on a house and didn't have the option. Maybe your builder just needs to use them once and like almost everyone else who has, he'll think they're really swell. He might be a great builder that doesn't trust something he hasn't tried, (there's more than a few folks around these parts that match that description). As far as the trunk line for your HVAC goes...unless you're considering a huge, open web truss system for a floor it has to go under or over but not through the joists. There is definitely nothing to worry about when building multiple stories. That first house I framed with the TJI's 8 years ago was three sories...it's still standing.

  5. Guest_ | May 31, 1999 05:20am | #7

    *
    Kay,

    Good points from everyone, here's my two cents.

    Chances are that the HVAC trunk line does have to go beneath the joists but that doesn't mean it can't be right next to the main beam (depends on the type of house). This centralizes the "low part" of the basement ceiling. All of the supply lines off the main trunk should easily fit in between the joists (again,depending on the house).

    Also let the builder know you want to minimize the interference of the plumbing as well. With some planning and a little extra effort, the waste pipes can be run between joists and along beams as well.

    You can also look at the option of having the HVAC contractor resizing the main trunk to be wider but not as deep (won't hang down as far).

    Webbed floor trusses can be designed for HVAC runs and it works great, especially for runs between floors. The contractor has to get a "meeting of the minds" between the HVAC sub and the truss designer, usually in the same room at the same time.

    If you do use that builder and it is his first time with TJI's, make sure he follows the instructions completely. They are very easy to follow. Mike Guertin and I wrote an article that was published by FHB not too long ago about framing floors with TJI's. I don't have the issue number at my finger tips, I'll see if I can find it.

    As for my opinion on TJI's; I'm building my own house soon and they will be used.

    Good luck,
    Rick A.

    1. Guest_ | Jun 01, 1999 04:11pm | #8

      *I've never seen everyone on this board agree on something as much as this thread !They're all correct, Kay - your builder just has it in his head that he doesn't want to use them. He's partly correct in being cautious about using them in a 2 story situation. This typically requires some sort of blocking at bearing walls. But it's not that big of a deal. Your builder just needs to follow the directions that the supplier furnishes.If the design of your house has bearing walls out in the middle of the span of the floor system, the person who designs you floor system definitely needs to take this into consideration. Best of luck with your home (and your builder)

  6. Greg_Harper | Jun 12, 1999 07:32am | #9

    *
    I agree with everyone else who has posted. I design these floor systems everyday. And if you go by what us designers put on our layouts, you will not have a problem. I seen all situations there are out there and this guy hasn't got a clue. I design alot of 2 story slab houses that you have to fit the first floor HVAC system in the floor system to avoid furred down ceilings. It may take changing a joist direction but all HVAC can be fit in the floor system without andy dropped ceilings.

  7. Kay_C. | Jun 12, 1999 07:32am | #10

    *
    Help, please, from folks who have used TJI's in floors. My builder has never used (and I suspect he is reluctant to start using). He says the trunk for the HVAC ducts would have to go under the TJI's, and that it has to go down the center of the basement. This would make the basement ceiling very low unless we take the foundation blocks up to 10'. Is he telling me the truth or justifying his wanting to use dimentional lumber?

    He also expressed concern over having two stories on top of the TJI's; he says that they would not support the weight. What say you?

    For general info, the house is a 30'x38' chalet
    with a daylight basement and a 12 and 12 roof. The second story in question is a loft with a master BR suite.

    Is he giving me the run-around? I suspect he might be because he "suggested" to my husband that he not let me watch Bob, Norm, JoJo, et al.
    I'm irked.

    Many thanks for taking time to respond to a woman in distress.

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