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Deck


Tom Breslawski

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Older codes generally permitted attaching beams to the sides of columns without resting on the beam. However, many of those connections probably did not comply with standards for bolted connections. So, depending on when this was built it may have been ok. The 2x members were probably added later. As someone else said, if they are resting on footings it may be ok, but even then I could argue that structural rated fasteners would be required because the fasteners prevent the 2x members from buckling.

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"Deck" screws are wood screws and are not rated for structural applications.

The screws are not being used for structural reinforcement in this case. All weight is heading straight down. Writing up screws in this situation is a needless complaint.

I disagree, Mike. The screws are under shear loads- glance at the rear post in the photo- it's evident that the ledger boards are just attached to the sides of the columns and no not rest on the footers.

Also, it's pretty unlikely that the 2X ledgers are rated for ground contact.

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"Deck" screws are wood screws and are not rated for structural applications.

The screws are not being used for structural reinforcement in this case. All weight is heading straight down. Writing up screws in this situation is a needless complaint.

I disagree, Mike. The screws are under shear loads- glance at the rear post in the photo- it's evident that the ledger boards are just attached to the sides of the columns and no not rest on the footers.

Also, it's pretty unlikely that the 2X ledgers are rated for ground contact.

You are correct Chad. I did write this up in the report. The 2x4's do not contact the footers.

This is another photo from the same deck.

Click to Enlarge
tn_2016130101632_IMG_0448.jpg

34.77 KB

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"Deck" screws are wood screws and are not rated for structural applications.

The screws are not being used for structural reinforcement in this case. All weight is heading straight down. Writing up screws in this situation is a needless complaint.

I disagree, Mike. The screws are under shear loads- glance at the rear post in the photo- it's evident that the ledger boards are just attached to the sides of the columns and no not rest on the footers.

Also, it's pretty unlikely that the 2X ledgers are rated for ground contact.

You are correct Chad. I did write this up in the report. The 2x4's do not contact the footers.

This is another photo from the same deck.

Click to Enlarge
tn_2016130101632_IMG_0448.jpg

34.77 KB

...looks like they have uplift taken care of anyway...except that the screws are also not the manufacturer's spec for the hardware.[:P]

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"Deck" screws are wood screws and are not rated for structural applications.

The screws are not being used for structural reinforcement in this case. All weight is heading straight down. Writing up screws in this situation is a needless complaint.

I disagree, Mike. The screws are under shear loads- glance at the rear post in the photo- it's evident that the ledger boards are just attached to the sides of the columns and no not rest on the footers.

Also, it's pretty unlikely that the 2X ledgers are rated for ground contact.

You are correct Chad. I did write this up in the report. The 2x4's do not contact the footers.

This is another photo from the same deck.

Click to Enlarge
tn_2016130101632_IMG_0448.jpg

34.77 KB

...looks like they have uplift taken care of anyway...except that the screws are also not the manufacturer's spec for the hardware.[:P]

That went in the report too. I think the homeowner liked deck screws. A lot.

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Most decks with beams not bearing directly over support don't even get this cleat treatment. Screws or not, how severely overloaded would this deck have to be before it failed? Have you ever seen carriage or through-bolts fail where beams are clamped to the sides of posts? Me either. Sure it's wrong and I would write it up in accordance with the deck guide. However, if you screw enough "Deck Mate" screws for the cleats on either side of those posts, is anyone going to fret during their next BBQ event?

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hspinnler,

...are you missing the point here? Decks fail routinely, regularly. Are the defects posted here likely to be life/limb threatening? No, if there is only a three foot fall as a result of catastrophic failure.

So you are qualified to brush off engineering standards for attachments?

Most of us here just cite the rules and issue common sense warnings.

I have seen decks underbuilt in ways I could not have imagined and have always issued warnings based on accepted standards...btw an in-law of mine leaned through a poorly fastened guard on a 2-yr old home at a wedding reception and fell eight feet to be ambulanced away in the dark.

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There were two deck screws in each cleat. The cleats were not bearing on the footer either. I didn't perform a formal load calculation, but common sense told me that two deck screws probably wasn't enough, so I decided to write them up as a potential failure.

Even though the deck wasn't very high, a surprise fall from that distance could cause quite a bit of injury.

Most decks with beams not bearing directly over support don't even get this cleat treatment. Screws or not, how severely overloaded would this deck have to be before it failed? Have you ever seen carriage or through-bolts fail where beams are clamped to the sides of posts? Me either. Sure it's wrong and I would write it up in accordance with the deck guide. However, if you screw enough "Deck Mate" screws for the cleats on either side of those posts, is anyone going to fret during their next BBQ event?

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It's not the height of the fall, it's the sudden start and stop that get you. The startle response puts your body in the worst possible state for the inevitable sudden stop. When an immovable object meets an unstoppable force, shit gets broken.

I fell 30" off a ladder. Landed on my heels with my knees straight. Compressed 3 vertibrae, crushed 3 discs, and up slipped and rotated my left sacroiliac. That was nearly 25 years ago. I still feel it every day.

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Decks are kind of like electrical work. Don't think too much. Just do it the way the book says and condemn anything that's not done that way.

The risk isn't now; it's 20 years from now. That's why we're seeing all those decks from the 80's and 90's collapsing nowadays.

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I don't know why you'd write up the cleats, or the screws in the cleats, or anything associated with them. The cleats aren't doing anything all. And their use even violates a basic rule of mechanical design.

You have two load paths of wildly different stiffnesses. One load from the beam and through the bolted connection to the post, then to the ground. That load path is very stiff. It's where all of the load is going. The load path from the beam through the cleat, through the screws, and into the post is extremely flimsy, even if you can install it in such a way that the cleat was originally able to take some load from the beam (which you can't). So that load path isn't taking any significant amount of load because it's so elastic.

It's a basic rule that you shouldn't have two load paths really at all, but especially if these two load paths have such different stiffnesses. Because you always want to know where the load is going, and you can't know that with two load paths of different stiffnesses. But in this case the load path through the cleat is clearly so flexible that the cleat is just window dressing and can be ignored.

Also, I know it's wrong according to the deck rules, but as far as I can tell no deck has ever failed because this type of bolted connection failed. If anybody knows of such a failure I'd love to hear about it.

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