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  1. #1
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    Nov 2008
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    Default Building partition walls under finished drop T-Bar ceiling

    In a commercial/retail dropped or suspended T bar type ceiling that is already finished and in place, how do you secure a partition wall that is built after the ceiling. What about if the ceiling wasn't built and the roof is very high, like most commercial spaces are? Do you frame all the way up and run the T bar at the finished ceiling height?

    I've always wanted to move into commercial work, but there are some aspects that I am clueless about.

    Are metal doors required, and why are they always KD (knock down)?

    Why are toilet seats open at the front?

    Metal studs required, or can you frame with wood?

    Does electric have to be in conduit?

    Does plumbing have to be cast iron and copper vent and waste?

    What other things are partial to commercial that is different from residential?

  2. #2
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    Default Re: Building partition walls under finished drop T-Bar ceiling

    I also wondered, when I see large soffits built under T bar ceilings, how are those secured.
    If the roof/ceiling framing is 16' high, the T-bar is at 12' with a soffit below, do you frame the soffit and build it off the ceiling. I'm guessing something with metal framing?

  3. #3
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    Jan 2005
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    Default Re: Building partition walls under finished drop T-Bar ceiling

    Some of those answers are dictated by code..

    Electrical generally is required in conduit.

    Walls are generally metal studs. I had to frame a load bearing platform and was allowed to use fire treated 2x6's and FT ply - nasty stuff.

    Doors might be a code thing; but I have installed wood doors in commercial provided they have the required fire rating. They all had metal frames however.

    I have not seen ABS in commercial - only copper and cast.

    Most ceilings grids are attached to the pan decking above, same with everything - light fixtures, wire runs, pipe runs and so forth, unless they are in a soffit.

    I have no idea about partition walls, I never installed a wall with out being able to tie it in to the grid above. I also have no idea about the toilets. :)

    The biggest change for me in commercial was fire code and sprinklers.

    I do not have tons of experience, but that is my experience.
    “Racism is man's gravest threat to man - the maximum of hatred for a minimum of reason.”
    Abraham J. Heschel (Jewish theologian and philosopher, 1907-1972)

  4. #4
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    Default Re: Building partition walls under finished drop T-Bar ceiling

    Quote Originally Posted by miterme View Post
    In a commercial/retail dropped or suspended T bar type ceiling that is already finished and in place, how do you secure a partition wall that is built after the ceiling. What about if the ceiling wasn't built and the roof is very high, like most commercial spaces are? Do you frame all the way up and run the T bar at the finished ceiling height?
    You can screw the top track into the t-bars or you can use caddy clips http://www.erico.com/products/CADDYcfcTwistOn.asp if you don't want to damage the grid. Some partitions are required to go all the way to the deck, fire separations for example. Some partitions are braced to the ceiling and some are free standing braced to each other. Generally partitions are framed a foot or so above the grid and a wall angle is attached to the wall to support the ceiling. There is no hard and fast rule on this.



    Quote Originally Posted by miterme View Post
    Are metal doors required, and why are they always KD (knock down)?
    Metal doors are not required. You can get fire rated wood doors and in most cases you can swing any door you like as long as it's not part of a fire separation. It is very important to have fire rated doors, hardware and frames in fire separations though.

    KD frames are a fast to install, inexpensive door frames. I don't see them very often except in store rooms and retail store back offices. The vast majority of frames I see are welded hollow metal, Aluminum partitioning system frames or wood.

    Quote Originally Posted by miterme View Post
    Why are toilet seats open at the front?
    That is a mystery.

    Quote Originally Posted by miterme View Post
    Metal studs required, or can you frame with wood?
    Within fire separations you can sometimes frame with wood although institutional buildings often require wall be built with no combustable materials in them. Once you start partitioning with steel you won't want to frame with wood. You can pick up a bundle of ten studs in one hand and run up the stairs with them, they store in 20% of the space that wood studs take up, there is no cull, they go together faster than wood and they are designed to be built between a floor and a deck. They are straight but drywallers still find ways to put bows in them.

    Quote Originally Posted by miterme View Post
    Does electric have to be in conduit?
    conduit or BX cable

    Quote Originally Posted by miterme View Post
    Does plumbing have to be cast iron and copper vent and waste?
    Yes in most places. cast and copper are non combustible so flames can't consume them and travel between floors

  5. #5
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    Jun 2004
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    Default Re: Building partition walls under finished drop T-Bar ceiling

    Quote Originally Posted by miterme View Post
    I
    Why are toilet seats open at the front?
    some of us are bigger, than the rest
    ;o)

    A big man made the 'Uniform Plumbing Code Section 409.2.2' requires an open front seat: "All water closet seats, except those within dwelling units or for private use, shall be of the open front type."
    Beware of the man whose belly does not shake when he laughs

  6. #6
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    Aug 2004
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    Fort Worth, Texas 76109
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    Default Re: Building partition walls under finished drop T-Bar ceiling

    Open front toilet seat. Health / hygiene purposes. At least that was what I have been told.

    For those with a bad back or is just to lazy and inconsiderate to put the seat up.

  7. #7
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    Aug 2009
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    St. Paul, MN & Northern WI
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    Default Re: Building partition walls under finished drop T-Bar ceiling

    Miterme:
    One of the big differences is that you start memorizing the IBC for your state instead of the IRC, many volumes . And, your’s will have voluminous comments on earthquake req’rmts. and all that other std. Calif. crazy stuff.

    Interior walls have vert. and lateral load req’rmts. for people forces, book shelves, etc. etc. so they either have to be cantilevered off the floor system or be supported at the top laterally. They can go up to the underside of real structure above, or just go up through the drop ceiling system with some diagonal kickers up to the structure above, for the lateral top support, at some structurally acceptable spacing. Fire walls generally have to span vertically from one fire rated surface to another.

    Generally, the drop ceiling system is not designed to take these wall loads, the Tees are primarily designed to take ceiling weight and some light misc. mech. equipment loads, such as light fixtures, misc. wiring, some light duct work, etc. i.e. 2-5#/sf DL and 5-10#/sf extra DL. It used to be wired up to the real structure above with heavy wire, allowing leveling, at regular intervals. And, out there you probably can’t get by the lightly any longer. In its own plane it takes its own weight/loads to the walls it butts against, at a wall angle.

    Cold formed, light ga. metal framing is certainly more common in commercial work than in residential construction. Many new tricks and tools to learn, the nails work different, but it’s light and straight and goes up fast once you learn the tricks. The slivers and saw dust are different too.
    Dick Hackbarth, PE
    RWH&AI, Consulting Engineers

  8. #8
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    Default Re: Building partition walls under finished drop T-Bar ceiling

    Quote Originally Posted by miterme View Post
    I also wondered, when I see large soffits built under T bar ceilings, how are those secured.
    If the roof/ceiling framing is 16' high, the T-bar is at 12' with a soffit below, do you frame the soffit and build it off the ceiling. I'm guessing something with metal framing?
    Usually the ceiling is independent of the bulkhead the bulkhead is built first the only part of the grid attached to the ceiling is the wall angle.

    Say the bulkhead described above is @ 11'6" aff and the grid id 12' aff and the deck is @ 16' That means the bulkhead is only 4'6" off the deck. You set your laser up at 11'6" aff attach a plate to the deck drop studs down 24" OC and cut them off just above the laser line then plate the bulkhead at the bottom and brace the bulkhead back to the deck plumb.

    You would then thread carrier channel through knockout holes in the stud ( when you frame you always have the knockout holes aligned) Then you install hangers in the deck and tie pencil rod between these hangers and the carrying channel in the wall. The pencil rod is what really carries the weight of the bulkhead and soffit.

    Once you get the bulkhead built and depending on the span of the soffit you can stud to form the soffit or build a suspended drywall ceiling out of furring and carrying channel or grid designed for drywall.

  9. #9
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    Jul 2008
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    304

    Default Re: Building partition walls under finished drop T-Bar ceiling

    I'm a drywall contractor and 85% of the work I do is commercial. We do a lot of work in the type your referring to. Tenant finish in large commercial buildings where the ceilings are ran first then all walls built underneath(except shafts/bathrooms/demising walls) take a look at these products...we use them pretty much exclusively except the frames...we use timely also

    http://www.eliminatortrack.com/

    This is a system used to make all the partitions look like they are underneath...it has a flange that looks like wall angle when the wall system is complete

    http://www.dunbarton.com/rediframe_o...rediframe.html

    These are the frames we use. They have a finish trim that goes over the frames or if you would rather install typical casing, you still can...just use wood bucks before you install or glue/cross nail your trim

    electrical isn't my field, but usually it is conduit or mc cable...which is a spiral metal jacket over wire

    as for the other questions...can't help you..but we usually do steel doors on exterior that aren't aluminum mullion type and fire rated wood on interiors

  10. #10
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    Default Re: Building partition walls under finished drop T-Bar ceiling

    Thanks for all the input guys.
    Is there a book or resource any of you can recommend in regards to steel framing, ie a primer or how to?

  11. #11
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    Oct 2007
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    Southern California
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    Default Re: Building partition walls under finished drop T-Bar ceiling

    For an example go to your local big box stores and take a look at how they did the offices and break room areas. You can generally see how it is all put together. Then start reading the code!
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  12. #12
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    Default Re: Building partition walls under finished drop T-Bar ceiling

    What I do not have a knowledge of is metal framing and for example the different types of tracks used. Are there bottom and top tracks that are different from stud framing? Headers, or is everything just built like a drop soffit? Do you fasten wood bucks to a RO for hanging doors? What is the best way to fasten wood to metal framing, for example if I wanted to add blocking for a cabinet run?

    Can I brace a partition wall with the ceiling joists to a neighboring wall that is already tied to the deck with kickers or does the new partition wall need its own kickers to the roof deck? Is it ok that the joists are wood and can you even use metal framing for ceiling joists? Do they make metal joists?
    What is the proper angle for kicker 45 degrees, or up to 45 degrees? How far should kickers be OC. One kicker each direction? Maximum length of a kicker. I the t-bar track connector seems like a good idea, is that code acceptable? I check out a few t bar ceilings with partition walls recently and I found that they seemed to just jam the top metal track of the wall to the t bar. I saw no bracing and no screws from the top track into the t bar.

    I can frame partition and bearing walls in wood all day, as I am used to it. But the t bar ceiling thing to me is all new and I am trying to learn about it. I like the metal framing stuff too, but I am all residential as are most of my subs so there is not alot I can glean from anyone. My framer actually frames commercial stuff too, but only wood framed jobs. All the build outs come after him.

  13. #13
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    Sep 2004
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    Default Re: Building partition walls under finished drop T-Bar ceiling

    I haven't heard of anything in the book stores.

    CGC's Gypsum construction Handbook is pretty good though http://www.cgcinc.com/en/resources/f...-handbook.aspx You can download it in sections as a pdf or buy it.

    I have a copy of the UBC's training manual for drywallers which is really good too. I don't know how you would get a copy unless you know a union drywaller

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