Lag screws through 5/8" Sheetrock
Lag screws through 5/8" Sheetrock
(OP)
I have a specification in a project for a ledger to be attached to 2x6 studs on 16" centers to hold a mezanine. The specification states that the drywall is to be removed and the ledger connected directly to the studs using 16p nails.
Could one use long lag bolts (say 5/16" x 6" and attach through the drywall instead?
Thanks,
Jim Marshall
Could one use long lag bolts (say 5/16" x 6" and attach through the drywall instead?
Thanks,
Jim Marshall






RE: Lag screws through 5/8" Sheetrock
RE: Lag screws through 5/8" Sheetrock
If the drywall is removed it seems like the lag bolts would be a better anchor than 16p nails. What size would be appropriate through an 1 1/2" ledger?
Also, could one support a 3/12 glue lam ledger at intervals, attaching with lag bolts to the wall through the drywall? In this way the bearing load would be on posts under the ledger.
Jim
RE: Lag screws through 5/8" Sheetrock
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RE: Lag screws through 5/8" Sheetrock
We had one where we lag bolted a ledger through a 1/2" plywood over a 2x4 wall. I know the drywall is different but it seems that there should be some way to get some bearing. Would it be possible to angle the lag bolts upward into the 2x6 or is there a specialty (eg Simpson) hanger that would accomodate this?
The load on the mezanine is hot excessive using 16" on center 16' TJI 230 joists. With a 100 psf storage loading and 10 psf dead load. The glue lam that the joist attaches to is a 6 3/4 x 18 spanning about 19 ft. If I had to I could put a glue lam against the wall and support it with posts I suppose.
Jim
RE: Lag screws through 5/8" Sheetrock
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RE: Lag screws through 5/8" Sheetrock
Angling the bolts upward into the studs could improve load bearing.
In addition I could support the ledger with periodic 2 x 4 posts attached to the wall studs. Thus, anchored horizontally with the lag bolts and supported vertically by essentially cripples, I believe it would hold.
Thanks again,
Jim
RE: Lag screws through 5/8" Sheetrock
I guess I don't understand your application because I still don't see how the lag bolts provide any "holding power" that opposes a bearing load being applied to the drywall.
Are you sufficiently confident in your approach to stamp the drawings?
Does your approach conform to UBC requirements?
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RE: Lag screws through 5/8" Sheetrock
The main concern was to make something that would be more easily removable. Puttying holes is easier than a new drywall job. There is still the option of using glue lam beams supported with posts up agains the drywall.
Jim
RE: Lag screws through 5/8" Sheetrock
Jim
RE: Lag screws through 5/8" Sheetrock
http://www.saradec.com/DeckManual/layoutd.htm
It looks like there might be a lot of bad information out there. The question, "Is there a legitimate way of handling this situation?"
Jim
RE: Lag screws through 5/8" Sheetrock
RE: Lag screws through 5/8" Sheetrock
My lbs per lineal foot on the mezanine is 660. Sounds like three rows into 2x6 studs at 16" oc would accomodate this quite well if not the ability to adjust for the bending factor. There was one article at http://ww
but there was not a lot of particulars.
Jim
RE: Lag screws through 5/8" Sheetrock
Jim
RE: Lag screws through 5/8" Sheetrock
Jordan
RE: Lag screws through 5/8" Sheetrock
Jim
RE: Lag screws through 5/8" Sheetrock
The only cantilevered fastener system was their ICF Ledger Connector System made for foam filled concrete walls.
Probably the only options without cutting the drywall would be to bolt the heck out of it and support it periodically with 2x4's lag bolted vertically to the wall. I am pricing also using 3 1/8 x 18 GLB that would have appropriate post placement. Although it is not necessary I would probably lag bolt it to the wall as well.
Jim
RE: Lag screws through 5/8" Sheetrock
I saw your post and had a couple of questions. In order to get the full NDS design value for a lag bolt, the penetration needs to be 8d, (4" min. for 1/2" diameter bolt), with a minimum pentration of 4d. If your load is 660 plf, a 1/2" lag has an allowable of 220 plf, you would need 4 total at 16" on center. How deep is your ledger? The spacing between bolts may be an issue. Is this a 2 hour rated shaft wall? This is an issue with stair wells that are wood framed. The gyp can't be penetrated and a ledger beam is needed to support the floor framing.
Another option if the situation allows it would be to place a two ply LSL board in the wall framing. The gyp would be able to run past. Provide a double LSL ledger board and connect it to the beam in the wall with thru bolts. The connection would require less bolts. It may work depending on your situation.
RE: Lag screws through 5/8" Sheetrock
I was thinking of using 6" x 1/2" plated lags. A friend suggested I use Simpson SDS structural screws (probably 1/4" x 6").
The wall is already in place.
Jim
RE: Lag screws through 5/8" Sheetrock
Did your calculations on the 1/2 lag at 220 lbs per lineal foot take into effect the 5/8" for the gypboard?
Jim
RE: Lag screws through 5/8" Sheetrock
RE: Lag screws through 5/8" Sheetrock
RE: Lag screws through 5/8" Sheetrock
The 220 plf allowable is from the 2001 NDS Manual for Wood construction. If the wall is constructed and sheathed, lag screws would be the best option. I would check with a local engineer to give you a sketch showing the spacing requirements for the bolts and a bolt size that will work. What is commmon practice in one area is not common everywhere. Good luck.
RE: Lag screws through 5/8" Sheetrock
He suggested a couple of over-building techniques. First, use a large ledger with multiple lag screws. Drill pilot holes for the lags through the ledger into the stud (says anyt lag over 1/4" needs a pilot hole. Then, use the pilot hole to bore a 1" or so hole through the drywall. Insert washers flushwith the drywall, bore the ledger and install the lag screws.
Secondly, he said if one is really concerned to lag bolt 2x4 flat against the wall to the floor to support the ledger.
Oddly enough I found that the lateral load value on a 5/16" lag screw is not appreciably less than a 1/2" lag bolt (220 vs 290 for 4" lag penetration in main member).
Thanks,
Jim
RE: Lag screws through 5/8" Sheetrock
You mentioned a concern about the placement of the bolts. An article from California Falsework manual Suggests a minimum spacing of bolts in a row to be 4D (diameter of bolt) with end distance at 7D from either end when in tension or compression. They also have an adjustment factor for multiple bolts relating to the cross sectional area of the main member, bolt spacing, and number of rows. The lateral load of the bolts are added and then adjusted depending upon number, main member, and bolt placement.
Jim
RE: Lag screws through 5/8" Sheetrock
I like the idea of notching out the drywall locations at the bolts and add the washers. A good way to keep the drywall from crushing.
The pilot holes are necessary to help keep the wood from splitting.
RE: Lag screws through 5/8" Sheetrock
Jim
RE: Lag screws through 5/8" Sheetrock
RE: Lag screws through 5/8" Sheetrock
RE: Lag screws through 5/8" Sheetrock
As for lag bolt vs. nail, either will work with adequate capacity. You'll obviously need more nails than lag bolts. In wood construction, it is better to keep the diameter down to minimize splitting. Stagger the bolts, also.
If you leave the drywall in place, the lag bolts will be under combined shear and bending. Check the interaction....it probably won't pass.
RE: Lag screws through 5/8" Sheetrock
Jim
RE: Lag screws through 5/8" Sheetrock
I also came across some information regarding deck attachment failures in Colorado. It seems that the 16d nails that everyone specifies have little holding power (although I am sure they have the shear originally) and the decks were slowly separating from the house and then collapsing.
Perhaps these requirements need to be revisited using bolts instead of nails.
Jim
RE: Lag screws through 5/8" Sheetrock
This may be a very late response, but I just wanted to tell you that I have specified the lag screw connection through the drywall in cases where the wall is fire-rated and the ledger is not allowed to interrupt the drywall. It may not sound like a good detail, but it works and I have never had any problems with it. I would say as long as the loads are reasonably low, go ahead and attach the ledger with lags through the drywall.
RE: Lag screws through 5/8" Sheetrock
Thanks,
Jim