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Thread: Wall Loads and Ceiling Sag

  1. #1
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    Dec 2013
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    Wall Loads and Ceiling Sag

    I'm sure this has been discussed, just couldn't find the thread(s).

    House/garage is about 20 years old. Reasonably well constructed (as far as I can tell). My workshop is a 3-car garage. 1-car garage door on one side. 2-car garage door on the other side. Floor-to-ceiling support between the garage doors. Mancave full bath on the backside of the 2-car side. Recessed area and stairs on the backside of the 1-car side. Stairs go to a BIG attic over all of this. There are no ceiling-to-floor supports across/inside the three (3) car bays. Makes for a nice big open area. Good and bad??

    To me, it's not a matter of will the ceiling sag....just when and how much. I try hard to keep all my attic "stuff" on the perimeter, as close to over the outside walls as possible, to minimize the load in the center of the attic/garage ceiling. I am very hesitant to build any type of ceiling-hung storage racks inside the garage/workshop. I do have wall-hung lumber storage racks, clamp racks, tool rack, etc.

    I've tried to Google/You-Tube calculations for wall and ceiling loads. I have found nothing, reasonably simple, that can tell me a) am I being overly concerned about additional low/moderate ceiling loads and b) safe wall loads.

    Should I install a couple of floor-to-ceiling pipe supports in the garage? I'd appreciate any suggestions, examples, or experiences (good or bad) that you might have.

  2. #2
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    Aug 2015
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    Any calculations or estimates will depend on the dimensions of garage ceiling joists (:: attic floor joists), ctr-to-ctr spacing, and what distance they span. If you know this info, then there are engineering tables to look up load ratings.
    Molann an obair an saor.

  3. #3
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    I was going to give you a link to a good online span calculator, but of course got sucked in ...

    https://www.awc.org/codes-standards/...tware/spancalc is not bad, but its geared to what span is allowed, not allowable loads. However, it re-enforces a dimly lit corner of cerbral clutter, that being 40psf live load + 10psf dead load is typical assumption for most residential framing. It also shows that 40/10 loads with SYP 2x12 @12"OC, will allow ~23' span.

    I have a recently acquired house/3-car garage (shop) with similar layout, and I assume, size as yours. The space above the garage is living area. While installing suitable lights and electrical for my shop, I had to determine joist layout and spacing. I found 14" I-joists w/ 3.5" flanges @12"OC, running perpendicular to the 'front' (entry) wall, and they used 2 or 3 web stiffeners in each cavity. Joists span ~26ft (with no mid-span columns). I believe the garage was built approximately 8-10 years ago, so perhaps not to same building codes as yours?

    Hope ^this^ helps, but bottom line is that you still need to know exactly what's there in order to calculate what it will support.
    Molann an obair an saor.

  4. #4
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    I have a similar situation with the exception that the second floor over the garage was designed to be living space and is completely finished. What it was not designed for was my 9', 2" thick slate pool table in the middle of the room. After I put the table in there was considerable bounce in the floor which made shooting pool interesting depending on which side of the table you were on. Talk about a home field advantage! My son-in-law and I installed a 26' long double 2x12 beam under the center of the table, perpendicular to the joists, and jacked it up tight to the floor/ceiling I-joists and stuck 4x4's under it. This was by far the easiest solution since the ceiling in the garage/shop is insulated, dry walled and painted. We cut the drywall out where the beam was going to be so we could make sure there was contact between it and the joists, and shimmed as needed. Problem solved.
    If you don't stand for something, you'll fall for anything.

  5. #5
    Join Date
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    You may or may not have a problem. I have an oversized three car garage with living space overhead and it has no support in the middle. It was designed that way. If the rest of your house seems well built, why do you think the ceiling joists in the garage are inadequate? This might not be the best forum to get an authoritative answer but you need to determine/furnish more information if you hope to obtain good advice. Here are some questions I would like answered before venturing an opinion. What is the maximum span of the ceiling? What is the joist spacing? Which way do the joists run? What is the size configuration of the joists/I-joists? Does the attic seem springy or unstable right now? Is there any sag right now as measured by a tight string stretched just below the ceiling?

  6. #6
    If the garage has no flooring installed in the ceiling, the ceiling is not designed for a large load to be added. Consider adding a beam and posts if you plan to add a lot of weight to the ceiling.

  7. #7
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    One way to proceed is to hire a structural engineer to analyze what you have and make recommendations. That puts all the calculations on someone with experience. For one project I found one through an architect friend and his rates were quite reasonable.

    JKJ

  8. #8
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    Quote Originally Posted by John K Jordan View Post
    One way to proceed is to hire a structural engineer to analyze what you have and make recommendations. That puts all the calculations on someone with experience. For one project I found one through an architect friend and his rates were quite reasonable.

    JKJ
    Sage advice, IMO.

    I bought my house with an attached carport. The 3rd winter after I moved in I helped a neighbor hang plywood on the interior of his newly built garage. As we were bringing my ladders back through 9" of newly fallen snow, we noticed a sag in the header over the 2 car carport. The idiots who built it put double 2x6 with a splice in the middle as the header across a 19' span. Measuring up 1 inch at each end, driving a nail, stretching a string tightly between nails, I measured to the low spot, subtracted that inch and got the resultant number of 2 3/8". It probably wouldn't have taken much more snow to put the roof on top of the two vehicles parked under it. The previous summer I had retrussed the roof because it was "soft". With accurate measurements I went to a local full service lumber yard to buy a new header. They contacted the company that made the headers. One of the company's structural engineers got on the phone with me. I gave the measurements, slope and load (2 layers of 30 year shingles) and he gave me the recommended header size to replace that header. I special ordered the header and replaced the scabbed one with 4x12 glu-lam. It's still doing great 30 years later.
    Ken

  9. #9
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    Quote Originally Posted by Bill Carey View Post
    I have a similar situation with the exception that the second floor over the garage was designed to be living space and is completely finished. What it was not designed for was my 9', 2" thick slate pool table in the middle of the room. After I put the table in there was considerable bounce in the floor which made shooting pool interesting depending on which side of the table you were on. Talk about a home field advantage! My son-in-law and I installed a 26' long double 2x12 beam under the center of the table, perpendicular to the joists, and jacked it up tight to the floor/ceiling I-joists and stuck 4x4's under it. This was by far the easiest solution since the ceiling in the garage/shop is insulated, dry walled and painted. We cut the drywall out where the beam was going to be so we could make sure there was contact between it and the joists, and shimmed as needed. Problem solved.
    Ha! Home field advantage reminds me of when we had a pool table built. We had the guy make the angles on the rails just a little straighter which reduced the entrance to the pockets. Basically, we played at home on a non-regulation table that was designed to be harder than any other. Then, when we played on other tables, it was like the pockets were 6" wide.

  10. #10
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    Cedar Park, TX (NW Austin)
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    I don’t see a problem with adding more support than what currently exists. Knowing whether or not it is needed is a question I can’t answer. If you add supports it might be a good idea to figure out a way to run electrical outlets to it. I work in a three car garage too and having outlets in the middle would be nice.
    Last edited by John Goodin; 10-26-2018 at 12:01 AM. Reason: spelling

  11. #11
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    Does this have the short perpendicular walls near the middle for support of the long walls? Put the beam on those and the span will be reduced by 6 feet or so.
    Those walls were built into my brothers 4 car garage in Oregon. not sure if they are for wind or seismic loads but obviously help with both.
    Bill D

  12. #12
    I had a similar situation when we moved into our current house. I called my city building inspector's office and explained what I wanted to do (how much weight, joist dimensions, span, distance between centers). They were delighted that I asked before I did something wrong, and were able to give me some guidance about what and what not to do. I also called a local engineering firm. Since I had the relevant parameters ready they were also quickly able to tell me how much weight I could safely put up there, and what mods I could do to increase the loads if that is what I wanted to do. Since they didn't have to make a site visit, they didn't even charge me. YMMV.

  13. #13
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    Robert,
    I am a Registered Architect, as such I cannot offer any advice other than....IF you are serious and really want answers, determine the existing structural conditions (framing members, spans, centering, supports, tributary area, etc) and then retain the services of a Structural Engineer or Architect (many Architect don't do their own calcs anymore). For any professional to offer an opinion based on the information here would be malpractice and advice offered by non-professionals is worth exactly what you paid for it.

    I don't want to demean any of the attempts to help or advise others have offered or to pontificate but please know that there is a reason Doctors, Engineers, Architects, Attorneys and other professionals went to school and preserved through their licensing processes. BTW- To become a Registered Architect I had to complete a 5 year college curriculum and serve a 3 year apprenticeship before starting the licensing process which included 4 written exams, a 12 hr design exam and an oral exam.

    Regards - Bill
    Last edited by Bill McNiel; 10-26-2018 at 9:07 PM.

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