Extra Wide Ledger Board

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Old 07-05-18, 09:14 PM
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Extra Wide Ledger Board

I am replacing a raised deck that is above a driveway. Its dimensions are 18’ (w) x 12’ (d)

The original deck is almost 40 years old and was built with 4x4 posts, 2x10 joists, and double 2x10 rim joists and header beam. There was no ledger board, but the house floor joists extended from the 2nd floor outside to create the joists for the deck.

Due to much newer code requirements, the new deck will have to consist of the following; 8x8 posts, 2x12 joists, 3 1/8” x 15” Glulam rim joists, and a 5 1/8” x 15” Glulam header beam. The joists will attach to the inside of the header beam using joist hangers (Simpson LUC210Z).

What I am trying to find out is, what’s the best material to use for a ledger board? The problem I am running into is those tall 15” glulams. To hang those using a concealed joist hanger (Simpson HUC216-2 2x16 double face mount hanger) it would seem that I need to have a 16” wide ledger board. I have not heard of lumber coming in sizes like this due to cupping, typically I have seen up to 2x12, and rarely a 2x14.

I would need something that is either treated or naturally resistant to rot, and ideally it would be nice if it was 2x material, but that is seeming to be very difficult. Has anyone ever run into an issue like that and came up with a creative solution?
 
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Old 07-06-18, 05:42 AM
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You would use another 15" wide glulam as your ledger. The huc216-2 hangers are 13 7/8" tall.
 
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Old 07-06-18, 06:16 AM
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Hi Minnino and welcome to the forum.
A couple of thoughts from less than an expert. I do believe in overkill but somehow your list of materials seems to go beyond what i have seen and heard for a 12' x 18' deck. A "3 1/8” x 15” Glulam" would be extremely strong and I'm not sure where you are putting that 5 1/8” x 15” Glulam header beam, but it could hold up a house. Are these materials listed in some deck building guide or code requirement? Remember, I'm just a thumb pounder.

One other concern is the existing ledger. I have removed several/many and after 40 years I would definitely expect some damage behind them. If none, hurray. But 40 years ago guidance wasn't what we see today so be prepared.

IMO, with 2x12 joists running 12' you don't need a 15" rim joist or ledger. If code is requiring that it would be interesting to see their language.

Best,
Bud
 
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Old 07-06-18, 06:25 AM
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I think the key problem is that he said it's over a driveway. It has to span 17-18 ft over the driveway, (16' + unsupported between posts) thus the glulams. And as for the ledger, the glulam (less bending moment stress and deflection) would not add significantly to the stress on the existing 16-18' long garage door header below... which could be close to being maxed out the way it is.
 
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Old 07-06-18, 07:03 AM
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Thanks XSleeper, using a 15" glulam as a ledger board is kind of my fall back plan, That is a giant and expensive piece of material though. The key issue with the design was the large span over the driveway, and the snow load here.

Bud9051 - I too think it is way overkill. The structural engineer said that a 5 1/8 x 12" glulam was not able to carry the load over the main header, so that went up a level to the 15" glulam. Also on the side of the deck that has the staircase, that rim joist had to be bumped up from double 2x12's to the 3 1/8 glulam. They used the 15" deep across the board for consistency to match the main header beam in terms of height since both the main header and the rim joists will be sitting on top of an 8x8 post.

As for the existing ledger, it was non existent. There is no band joist at the end of the floor joists. After getting the siding off, it looks like the joists between the 1st and 2nd floor were extended outside of the house, which because the joists for the original deck.
 
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Old 07-06-18, 11:03 AM
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Had a set of drawings drawn up by an over enthusiastic young engineer who totally over designed everything. I needed drawings to submit my application but talked to the city code person about the ridiculous overkill. They agreed and signed off on some more reasonable requirements. My point is, engineers are protecting themselves as well as your house but you have to pay for their protection.

You said "The structural engineer said that a 5 1/8 x 12" glulam was not able to carry the load over the main header," Just my exaggeration, but a 12" x 5" glulam 12' long was already overkill from the start. But I'm not there so ignore me please.

Bud
 
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