Adding some 1/2" bolts to ledger

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Old 10-18-13, 12:03 PM
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Adding some 1/2" bolts to ledger

I was planning to add a few thru bolts to my existing deck ledger for added strength.
I have a few questions.

DCA6-09 says to pre-drill holes of diameter between 17/32" and 9/16".
The only drill bit I can find locally is this one for $4 at Lowes: IRWIN SPEEDBOR 9/16-in Woodboring Spade Drill Bit. Would this do the job or is it too crude?
The perfectionist in me says to spends $15-20 on a special order 17/32" (non-spade) bit and with a week for it to arrive, or is the spade bit just fine?

Also do I need to use a caulk or sealant?

Anything else I should watch out for?
 
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Old 10-18-13, 12:45 PM
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Spade bits can work if you are able to get in a position to push well on the drill otherwise I'd go for an auger style bit that will help pull itself through the wood. Depending on how much wood you have to go through getting a 1/2" hot dip galvanized bolt through an undersized hole will take some pounding so make sure you have room to swing a mallet. Or just drill 1/2" holes and make everything easier. The bits are easier to find and it will be easier to get the bolts through the holes.

 
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Old 10-18-13, 12:56 PM
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Remember, too the washer that you must place on the head of the carriage bolt will be one size larger than the bolt shank. 1/2" bolt will take a 3/4" washer under the carriage bolt head, and 1/2" washer under the nut.
 
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Old 10-18-13, 12:58 PM
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Thanks for the reply.

I actually already have a 1/2" auger style bit. The code calls for a pilot hole slightly larger in diameter (by 1/32" to 1/16") than the bolt. I guess this is to allow for contraction of the ledger board - don't know how much of a concern this would be in a 10+ year old ledger board.
 
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Old 10-18-13, 01:01 PM
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Hi Chandler,

I was planning to use a hex head galvanized thru bolt, not a carriage bolt. I presume I would use a 1/2" washer on both ends.
 
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Old 10-18-13, 01:15 PM
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Yes, that would be correct, but the washer is called for. I just didn't want you down at the Depot buying 1/2" washers for a carriage bolt head application. The 9/16" hole is so you can send the bolt through the hole without having to drive it through with a 3# hammer. You can drill your 1/2" hole with the existing auger, then chase it with the $4 9/16 spade for the extra room if you want.
 
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Old 10-21-13, 10:50 AM
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I would never use a spade bit to enlarge a hole, because for it to function properly, the sharp center-point needs to be embedded in solid material (not wallowing around in thin air). The sides of the bit will catch material, and want to lock the bit up. Good way to break a wrist.
 
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Old 10-21-13, 12:50 PM
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Thanks for the replies.

I picked up a 9/16" spade bit with auger tip at Home Depot.

Since the hole will be a little larger than the bolt is it necessary to use some caulk or sealant or will the washer seal things enough?
 
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Old 10-21-13, 01:52 PM
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Add some caulking, in the hole before and after bolt- under the washer. Drill new holes and leave the existing fasteners alone, or is that your plan. Time/energy spent, special bit, etc. Add a continuous (thick) bead of caulk on the drip-edge of the ledger (or within 1/4" back); bottom edge closest to the deck- to force water to drip rather than capillary wick to the siding on house.

Gary
 
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Old 10-21-13, 06:57 PM
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Hi Gary,

Thanks for the reply.
Yes I intend to leave the existing fasteners untouched and add some new bolts in new locations.

As far as caulking - you are suggesting in 3 areas.
1. around the bolts
2. the bottom edge of the ledger
3. between the siding/trim and where it just touches the top edge of the first deck board.

I don't see much downside to item 1.
However I was unsure about items 2 and 3 - there currently is no caulking there and I wondered if I would do more harm than good by potentially trapping water in as opposed to blocking water from wicking back in. You believe both are a good idea?
Currently the siding/trim comes down and touches the floor board tightly and there is no caulk. Should I stick with this but add caulk? Or leave a small gap and caulk/not caulk? Any particular type of caulk?

Thanks,
John
 
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Old 10-21-13, 08:08 PM
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I add some caulking around the last 2" of the bolt and around the washer so some oozes out with bolt set. No caulking above deck surface, requires flashing to drain (should be already installed against wall/under house side decking board. Caulking along bottom of ledger---- on the outside edge_ so water from flashing/house spills down and DRIPS of the wide face of ledger- caulking is on small face of ledger; bottom only. This stops any wind-blown rain/capillary wicking of water from entering or even getting to the house/ledger joint under same. You could caulk along the house/ledger bottom joint if ledger was not flashed with sticky wrap before install, OR leave it be as is.... bug entrance... or need a water vent?

Gary
 
 

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