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garage loft; ledger to ledger joists?

45917 Views 12 Replies 9 Participants Last post by  Nealtw
I am working up plans for a garage loft and seek some wisdom from the many wise folks here. Many humble thanks in advance.

I intend the loft to span the entire width of the garage. The garage is quite small spanning 11'4" from wall to wall. Each wall is load bearing and constructed with 2x4, 16" OC. In an effort to avoid installing posts and securing them to the garage floor, I am considering fastening ledger boards to each side wall and hanging from them joists to run across the 11'4" span.

Attached you'll find a simple illustration of the proposed plan. The scale is a little bit off but quite adequate for discussion I feel. The illustration shows just one side of the proposed loft. The same methodology would be applied to the other side of the loft. You'll see veritcal 2x4 wall studs with a doubled 2x8 ledger supporting 2x8 joists.

Since the drawing is not annotated, here are some details of the plan with a couple questions following -

* all lumber is douglas fir-larch structural grade.
* ledger board: doubled up 2x8 attached to the 2x4 wall studs with two 1/2" x 6" lag screws at every wall stud.
* joists: 2x8 16" OC attached to ledger board with double shear Simpson joist hangers via 10d common nails.
* floor: tongue and groove ply ( unsure of thickness )

justification for the doubled up 2x8 ledger: I want to fully receive a 10d common nail (3" length ) driven through the joist hanger and into the face of the ledger.


and finally a couple questions:

ledger to ledger construction: In all my perusing of the diy and construction sites, I have never seen this type of design used before. This suggests to me that I have steered myself in the wrong direction. A bit of an open-ended question - is this a sound approach? span and load calculations have been done and I know the 2x8 16" OC is actually quite overbuilt. Its just the ledger - ledger connection that I am concerned with.


lag screws: I am a bit fearful to use a lag screw to mount the ledger since nearly every resource I have found thus far suggests that lag screws are not held to any sort of manufacturing standards. As such, they have no strength ratings. Rough estimates of 60% tensile strength are about as good as it gets. Outside of a lag screw, however, what real alternatives exist? I don't see a Simpson strong tie that addresses this type of connection.

The joist hanger I am looking at recommends using 16d common nails into the face and 10d common nails into the joist (double shear so is toed in through the joist and ledger). Given that the ledger thickness is 3", I have opted to use 10d common ( 3" long ) nails as a substitute to the 16d common (3 1/2" long). Would it be better to use the 16d common nail into the face even though there would be 1/2" protruding from the back side of the ledger? I do not know the trade-off between the fully sunk 10d and the slightly protruding 16d.

Thanks for reading through and thanks even more should you choose to reply.
-brian

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The ledger board that I installed for my cathedral ceiling (flat part) I nailed. The Inspector required it to be lag bolted

I would install a board going across as a "ledger", lag bolt it in & nail it - if that make you feel better
Then land the 2x8's on top of this board for support
2x8's should work for that span, depending upon the wood
I woud not use a 2x ledger board

Span calc:
http://www.awc.org/calculators/span/calc/timbercalcstyle.asp

If you're existing garage wall are open line each joist up with a stud
Nail each joist to the side of the stud & toenail to the ledger board
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Personally, my shed got done this way. I feel the dadoed inset 2 x 4 makes all the difference... you aren't then just relying on the bolt to carry shear.

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lag screws: I am a bit fearful to use a lag screw to mount the ledger since nearly every resource I have found thus far suggests that lag screws are not held to any sort of manufacturing standards. As such, they have no strength ratings. Rough estimates of 60% tensile strength are about as good as it gets. Outside of a lag screw, however, what real alternatives exist? I don't see a Simpson strong tie that addresses this type of connection.
Lag screws suck. For a little more money Fastenmaster has a much better product called LedgerLok.
Willie's method would be the strongest. 1/2" lags have a shear of 200#, wood to wood. The LedgerLok has a shear of 241#.

The Simpson SDS (quite similar), has a shear of 240#.

http://www.strongtie.com/products/connectors/screws.asp

With two in each stud, you are only at 480#, with the 2x8's capable of carrying 510#. The hangers are at 1055, with 10d's. Why not single header joists and LU2x8 hangers, with 1-1/2" nails and 890#? I would think if you ran the ply decking, wall to wall, you would pick up shear flow, but you are in CA, the hangers wouldn't even work. (if under the LA code). Again, Willie's hit it on the head. Be safe, G
Thanks for all the information on lag bolt alternatives. The LedgerLok and/or the Simpson SDS products look like a good solution.

Willie T : Seems there is some consensus that your proposal is the best way to go. Thanks for the excellent drawing illustrating such. Any shear concerns are certainly minimized with this approach. I like it a lot!

If I may, one followup question concerning the dadoed stud with inset ledger board -
If I were to go with this method I would be putting dado cuts into 2x4 studs of a load bearing wall. Is this of any concern to anyone? Certainly the load of the ceiling would be temporarily braced during the ledger installation, but aside from that are there other things to consider?

Thanks again,
brian
Willie may have a better way, I would over-cut the top dado only, by a saw blade thickness. Install the ledger, drive opposing shims in. The roof load would transfer down efficiently. Be safe, G
GBAR is right. You will seldom get a good level cut all the way across. Shims can sure help you fine tune it and tighten things up.
Hello, I know this is an old thread but may be the right place to seek my answer.

In my garage, I have a partial loft area from the wall to the middle of the room, which is secured to the rafter on the roof.

I'm afraid that the weight from everything is too much for the roof.

It looks crude to me. I'd like to re-do this the best (right) way! It would also open up more space for storage.

I want to span the loft to both sides of the garage. about 13 feet wide.

What is the best way to support a storage platform to both sides of the wall?

Which type/size of lumbar would I need to use for cross beams and thickness for the platform?

I have attached 3 photos to show...


Thank You for your time...

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Nick M go back and start your own thread, you have some issues with what you have there.
PLS HELP!!! many hours of scouring internet, and nothing comes even close to my plan, questions and concerns....until i finally came across yours!! please share what you've learned or what you would do differently, now that you've had it for several years.
PLS HELP!!! many hours of scouring internet, and nothing comes even close to my plan, questions and concerns....until i finally came across yours!! please share what you've learned or what you would do differently, now that you've had it for several years.
This is very old I think you should just post a question in a new thread. :wink2:
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