Replies

1. 
   jjwalters | Mar 24, 2002 02:45pm | #1

   Good idea, but the info's a little fuzzy. Beings that it's an old garage, why don't you get someone locally to look at it? and check the foundation/side walls, etc.

   There are fast carpenters who care..... there are slow carpenters who care more.....there are half fast carpenters who could care less......what are you?

   
   

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   Edited 3/24/2002 7:47:38 AM ET by JJWALTERS

2. 
   Davo304 | Mar 24, 2002 09:55pm | #2

   "Presently I have 2X8 joists running overhead..."

   If you are talking about ceiling joists, you have no worries. Lots of ceiling joists are spaced 24 inches OC. This would be adequate to hang your drywall to.  I like to hang ceiling drywall using drywall screws instead of nails.  You can purchase fiberglass batt insulation that will fit between 24 OC joists, but its just as easy to first install your drywall, and then go back and install blown in cellulose insulation between the joist bays.

1. 
   Fabrizio | Mar 27, 2002 05:50am | #3

   Davo, wouldn't I be better off putting in more ceiling joists for added support to the overhead panels, and lights, etc.? Just curious.

1. 
   JohnSprung | Mar 28, 2002 01:47am | #4

   What's above those ceiling joists?  Is it attic space that you might some day want to use for storage?  If so, what's the span of the joists?  If the span's short enough, and you want the storage space, adding joists to bring the spacing down to 12" oc might be a good idea.

   -- J.S.

1. 
   Fabrizio | Mar 28, 2002 05:37am | #5

   Nothing is up there other than trusses. By city code, I'm not permitted to add any more onto the building because my square footage after the wifes attached garage is added will exceed 1000'sq.; so all I can do is insulate.

                                                                                       Eddie.

2. 
   Fabrizio | Mar 28, 2002 06:03am | #6

   There's nothing up there other than the trusses. I'm not allowed by the city to build anymore onto the structure as it would exceed 1000' sq. and so all I can do is insulate and build within.

                                          Eddie

1. 
   Davo304 | Mar 28, 2002 08:33am | #7

   Question: " What's above your ceiling joists, attic space?"

   Answer: "Nothing up there but the trusses."

   OK, hold the phone.  Earlier, you said your garage had 2X8 ceiling joists, 24 inch OC.  I probably should have asked you what the span was but I assumed the span was within normal limits and you simply wanted to add lighting and drywall. At 24 inch OC, this is not a problem. 

   Now you state you have trusses, not rafters. What type of truss do you have, scissor, attic,  gable, or some other combo?  Just curious.

   If this "2x8" is actually the bottom chord of  a designed attic truss, you have no worries. This type of truss is designed to handle a floor load for the attic space. And, you say you have no storage and the joists are "open" so you presently have no floor load. right?  Well then,your ceiling's drywall weight and shop lighting fixture weight will be a much lighter load than compared to what it was designed for. 

   My garage is trussed with gable trusses (built out of 2X4 materials, including bottom chord) that are spaced 24 inch OC.  The trusses span 24 feet. The length of my garage is only 36 feet long.  I have 12 sets of flourescent (4ft. shop lights) attached to my ceiling and paneled it with 1/4 inch luan  that I had on hand. I also attached 3/4 thick plywood to the top of the bottom chord down the center of the truss run and used this area for storage. I even cut one truss chord ( which you shouldn't do unless approved by designer/engineer) and "boxed in an attic stairway so I could get to this storage area.  That was over 5 years ago. My ceiling is just fine.

   What I'm getting at is ,if your current joists meet code as far as spans, then a 2X8 can easily handle 1/2 inch or even 5/8 drywall and normal shop lighting.

   If, however, this concerns you and you would sleep better at night by installing additional joists, then install  another 2X8 joist between each existing one, which will give you a 12 inch OC spacing. Its your money.

   An easier solution (if your main concern is slight joist sagging) is to install a "strongback."  A strongback is nothing more than a 2X4 nailed perpendicular across the tops of the ceiling joists. This 2X4 is faced nailed flat to the joists. Then  another 2X4,  2X6, or 2X8 (your preference) is nailed into the edge of this 2X4 so to form an "L" shaped brace.  This strongback will keep the joists from sagging.

   Run this strongback towards the middle of the span where you think it will do the most good. Run it the full distance from one end to the other. Cut blocks the same hieght as your joist (7-1/4" for a 2X8) and nail them on the 2X4 at each end so the strongback can be tied to the topplates as well.  This is a lot easier and less expensive than adding joists, especially if all you intend to do is to add a lightweight ceiling and lighting.

   If you intend to make garage into another floor level, then beefing up FLOOR JOISTS is always a good idea. But I thought we were talking about CEILING JOISTS, not floor. If you intend to install overhead jib crane or a 3 ton hoist or something, then , YES by all means beef up your ceiling joists. You never stated any of these intentions and so I take your post at face value.

   Is there more here than you are telling?

   Davo

   Davo

2. 
   Fabrizio | Mar 29, 2002 12:06am | #9

   No you've pretty much answered my questions. Thanks, it's nice to get a second, third, or even fourth opinion.

3. 
   Davo304 | Mar 28, 2002 08:53am | #8

   Here's a good website concerning joist spans, rafter spans, and such. Hope I post this right.

   The sight is referred to as the Online Span Calculator.

   Try this:  http://www.cwc.ca/design/design_tools/calcs/SpanCalc0399/Span_US.html

   Davo