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Old 07-02-2008, 11:55 PM   #1
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Deck Beam - staggered


Hi,

I have a question. I have a deck that is about 6' off the ground. I have 4 4X4 post set in concrete that is 30" in the ground (for the frost line) and the posts in post based that are set in the concrete. The length of the deck is 34'. I did a (2)2X10 beam by staggering 2X10X12's and ended up with 2X10X6 sections completing the ends. With help from friends, obviously the beam was placed on the posts and set in the post holders on the top of the 4x4 posts. Now, this is staggered and I have the beam connections not connecting on the 4X4 post.

I have 3 2X10X12's on one side Then I have pressure treated plywood cut at 10X width and placed on top of the 3 2X10's. Then I have a 2X10X6 nailed into the plywood and then the bottom layer. Then another 2X10X12 next to it, then another 2X10X12 and then completed the length with another 2X10X6. The butting of the first layer of 2X10X12's are covered with the plywood and then the second layer staggers over those butted connections as well.

My question is that structurally viable? The other question is should I put a steel plate bolted through the first and second side at the points where the butted connections are to further strengthen or enhance the structural viability of this beam?

Any info would be greatly appreciated.

Thanks!

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Old 07-03-2008, 06:44 AM   #2
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Deck Beam - staggered


No idea if ok or not, but I'd suggest a picture or two might help those who know offer an opinion.
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Old 07-03-2008, 07:50 AM   #3
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Deck Beam - staggered


The description got pretty convoluted, but I think I get the basics. Essentially, you're splicing a beam between bearing points.

I think you've made a big mistake in not using the correct lengths of lumber to hit your bearing points. The plywood is of no value unless it is 100% protected from the weather. Even if it is, it is of very little structural value.

The addition of a steel flitch plate of an unknown thickness may be required. An engineer would need to be consulted.

First, check with the inspector that will be looking at it. He'll likely pick up on this right away, and you need to know if he'll allow it or not. On a deck (higher live load design), I would not, unless the span was incredibly short.
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Old 07-03-2008, 08:44 AM   #4
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Deck Beam - staggered


? 4 4x4 posts 6' above grade on a 34' span (from your info above)

hum.... 1 for each corner so are the posts a little less than 12 oc?

depending on your load

I think you will need more posts.... please advise layout.

also advise detail of how you made the beam. nail oc ...adhesive...
sandwiched exterior plywood between 2x's
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Old 07-03-2008, 10:33 AM   #5
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Deck Beam - staggered


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Originally Posted by davis_mc View Post
Hi,
I have a question. I have a deck that is about 6' off the ground. I have 4 4X4 post set in concrete that is 30" in the ground (for the frost line) and the posts in post based that are set in the concrete. The length of the deck is 34'. I did a (2)2X10 beam by staggering 2X10X12's and ended up with 2X10X6 sections completing the ends. With help from friends, obviously the beam was placed on the posts and set in the post holders on the top of the 4x4 posts. Now, this is staggered and I have the beam connections not connecting on the 4X4 post.
I have 3 2X10X12's on one side Then I have pressure treated plywood cut at 10X width and placed on top of the 3 2X10's. Then I have a 2X10X6 nailed into the plywood and then the bottom layer. Then another 2X10X12 next to it, then another 2X10X12 and then completed the length with another 2X10X6. The butting of the first layer of 2X10X12's are covered with the plywood and then the second layer staggers over those butted connections as well.
My question is that structurally viable? The other question is should I put a steel plate bolted through the first and second side at the points where the butted connections are to further strengthen or enhance the structural viability of this beam?
Huh?

Honestly, the whole thing sounds scary and is not per normal deck structural design.
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Old 07-03-2008, 03:51 PM   #6
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Deck Beam - staggered


Even with a solid pair of 2x10s, you can't span the 11+ feet between your posts. A spliced beam will sag big time. The tributary length of your joists also plays into this equation.
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Old 07-03-2008, 05:26 PM   #7
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Deck Beam - staggered


Here are some pictures of what I have. What the pictures does not show is that there are 4 4X4 posts supporting that beam and the beam is also connected to a ledger on the house. (the first one shows that actually)

I guess I am very confused on this because it's not sagging and it is very, very strong. (At least it seems like it to me. I can't budge this thing at all but then again I shouldn't be able to.)

thekctermite, the inspector did reject it. I have consulted an engineer as well. What the engineer said is to put another 2X10X10 over the beam at the point of splice. Nail a 2x4 against the 4x4 post and put the 2X10X10 on top of it and nail it to the existing beam. The 2X10X10 will span the 4X4 posts and cover the splice of the beam. It will then be supported by the 2X4's that are nailed to the 4X4's. The concern I have is that whatever reason for covering the splice is supported by a 2x4 and nails in that 2x4. There is only like 2 places that you see in the pictures where that would need to be done I can cut the ends at 45 degrees to make it look asthetically pleasing. On the inner side of that beam fowards the house nobody is really going to see. An interesting little thing too when I spoke to the inspector regarding this as well he said the wood (2X4) does NOT have to be pressure treated. It's exposed to the elements. WHY NOT?

The other way ithat could've been done does not seem to be something that sounds very plausible either. Basically having like 2 inches of a 4X4 support part of the beam and 2 inches supporting another beam. If wood can rot (even though it's ACQ or pressure treated) which it can over time and it does that on the 2" of that post supporting that beam; I would believe that is very, very bad.

TO BOOT: the engineer did find that what the regional building department approved on the plan and permit on a different part of the deck was NOT adequate support. Said I need to change that and it going to draft a letter to the regional building department supporting the statement for change. Makes me think...what the heck are we having the inspections for when they don't even get it right and inspectors are inspecting what they don't have right? The engineers work with the regional building department and are certified which I can only assume is why inspectors oblige what the engineers provide information on.

In addition, the engineer said a steel fitch plate will not work. The engineer is looking into other possibilities as well but the quick item is what was mentioned above.

Also the plywood was just filler and it used to bond the 2 layers.

Hope this helps.

Anybody have any other ideas or possiblities?
Attached Thumbnails
Deck Beam - staggered-img_0093-1-.jpg   Deck Beam - staggered-img_0094-1-.jpg   Deck Beam - staggered-img_0095-1-.jpg   Deck Beam - staggered-img_0096-1-.jpg  
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Old 07-03-2008, 11:01 PM   #8
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Deck Beam - staggered


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Originally Posted by davis_mc View Post
TO BOOT: the engineer did find that what the regional building department approved on the plan and permit on a different part of the deck was NOT adequate support. Said I need to change that and it going to draft a letter to the regional building department supporting the statement for change. Makes me think...what the heck are we having the inspections for when they don't even get it right and inspectors are inspecting what they don't have right? The engineers work with the regional building department and are certified which I can only assume is why inspectors oblige what the engineers provide information on.
Sorry friend, but that's a sad attempt to put blame on the building department for your mistakes. The building department is not a design service. Yes, they should have caught obvious structural design issues on the front end plan review when the job was permitted, but the ultimate burden of doing it right rests on the permitee.

Why the heck are you having inspections? One good reason is mistakes such as splicing the support beam in the span between the bearing points.

You're right about the inspectors obliging the engineers. The code allows inspectors to accept 3rd party engineering to circumvent structural deficiencies, or address issues that the prescriptive methods in the code doesn't cover. I bet for what that engineer cost you, you could have probably bought new rim board lumber and replaced it instead of trying to find a way to make it work. But, it sounds like it is good that you had him come by since he found a separate issue.

The 2x4's you're talking about don't have to be treated lumber, but would have to be a lumber that is allowed for use in an outdoor environment. That would include cedar, redwood, and a number of exotics such as Ipe. Regular framing lumber would be a no-no outdoors.
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Old 07-04-2008, 06:24 AM   #9
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Deck Beam - staggered


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Originally Posted by davis_mc View Post
I guess I am very confused on this because it's not sagging and it is very, very strong. (At least it seems like it to me. I can't budge this thing at all but then again I shouldn't be able to.)
You can build a basic frame out of 2x4's and it's going to "seem" solid. The point of proper structural building, is "what" the finished product is going to support over the span of time, and what it's intended use will be. Example: You have no real distributed weight-loads on that yet. Dead load + live load: railings, decking, outdoor-furniture, etc + people.

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Originally Posted by davis_mc View Post
thekctermite, the inspector did reject it. I have consulted an engineer as well.
You are ultimately going to be subject to what the town/city approves, not what the engineer "tells" you.

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Originally Posted by davis_mc View Post
Anybody have any other ideas or possiblities?
IMHO: Basically, you are way in over your head. If you had hired an experienced deck builder, you would not have wasted so much time, money, and energy, trying to understand all this, and get it approved.
Honestly, you are better off at this point, hiring a licensed professional, with an understanding of structural building and codes, to come in and basically....take it all down, re-use the lumber that is re-usable, and build you a nice, safe, structural deck. One that the town/city will not reject.

Last fall, we were on a whole-house, complete remodeling project, that a new home-owner had tried to start doing himself. One of the "sub-projects", that we did, per his approval, was rip down an entire composite deck that the same Home Owner had recently built. It had flunked inspection; No flashing used, stairs not to code, deck surface higher than the entry threshold, etc... That was an expensive, failed, "hobby-project" for him. At least you are seeing the mistakes early on. You can still hire this thing out and bounce back from it financially.

Best of luck in getting this sorted out.

Last edited by AtlanticWBConst.; 07-04-2008 at 06:32 AM.
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Old 07-04-2008, 08:46 AM   #10
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Deck Beam - staggered


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Sorry friend, but that's a sad attempt to put blame on the building department for your mistakes. The building department is not a design service. Yes, they should have caught obvious structural design issues on the front end plan review when the job was permitted, but the ultimate burden of doing it right rests on the permitee.
I have to respectfully disagree with you. It's not a sad attempt; it's reality. Clear cut reality. Granted, I will acknowledge a mistake on my part but that blame has to be shared. The RBD should have clear-cut information on not splicing a beam on joists. They don't. Even the inspector mentioned that. In addition, the inspector also acknowledged that fact that the change on building codes so often and inconsistently it's ridiculous. I cited and he concured - the ccq wood debacle.

Also, I do not claim to be a licensed contractor but I have done 3 decks helping friends that HAVE been approved by the regional building department and are still standing and just fine.

The cost of the engineer offsetting replacing that beam? I don't know where you are coming from friend, maybe the inspector-side, but the time is money and the cost of ripping out all that and replacing the beam does not outweigh the cost of the engineer. (again, the reference to the "inspector-side" is with much respect). The inspectors do an incredible job but they make mistakes as well and sometimes big ones. Like the approval and calculations for load-bearing and support on the other part of the deck. I pay a price to have a plan check for the permit and it's not cheap. I expect to have quality verification and confirmation of my adjustments for what I'm paying for.

The cost of making these adjustments for a structually sound deck according to the RBP is about $70 from what I already have with respect to materials. How does that make sense to hire a licensed contractor to tear down and rebuild?

I'm sorry, I'm do not have a lot of faith in this process in it's entirety. I am probably still very resentful of the fact of my house. The house was bought brand-new and built. This was done by licensed contractors. The RBD DISAPPROVED the final inspection on my house and guess what... I was young and ill-informed but the house was sold to me with that situation. Which again puts to question the inspections. It should be more of a guidance to HELP with the design.
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Old 07-04-2008, 09:41 AM   #11
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Deck Beam - staggered


I do have to state though that this is the first deck that I have done of this nature with a consistent span of 34'. I have done decks (2 others) and my other house of with a max of 27' but that was with a step-up. As mentioned, those were all approved by the regional building department (RBD). Again, this is the first with a consistent span. That from what I'm hearing was a big mistake but it is workable from working with the engineer at a cost that is not out of budget and it will still have the asthetics. In fact, we're still under budget and reasonable time on the deck by about $200 even with having to get the enginner and having to also readjust the other part of the deck.

I should've posted the question on this site before I did that beam though. Mistake #2. :-(

But I'll get through this one and still have a quality deck.

Inspectors are a good source for confirmation and I value that.
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Old 07-04-2008, 09:56 AM   #12
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Deck Beam - staggered


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Originally Posted by davis_mc View Post
The RBD should have clear-cut information on not splicing a beam on joists. They don't.
Maybe I'm reading this wrong, but if you expect the building dept. to explicitly tell you everything you SHOULDN'T do when building a deck, you expect too much. Common sense would dictate that if a beam is holding up a large weight, the ends of the beam should be supported. Period. That's "Building 101."

Yes, yes, I understand, it's everyone else's fault but yours. You're just young and ill-informed and everyone else needs to look out for your best interests. Give me a break. You want to build a big, elevated deck? Go buy yourself $200 in books (Taunton Press has good stuff), read up on the proper way to build a deck, and educate yourself. I won't even say "Hire a real deck guy" 'cause I get the feeling you'd be a nightmare customer for him...

Here's a tip -
Pull all the nails connecting your joists to the beam.
Temp support your joists with a temp beam - push the joists up so they're sitting 1/4" above your current beam.
Pull out that scabbed together piece...
Build a new, properly built-up beam (you can build it in place on the posts if it's too heavy to lift)
MAKE SURE THE BEAM JOINTS ARE DIRECTLY OVER THE POSTS.
Install the new beam.
Pull the temp beam down.
Reaffix the joists to the new, properly built beam.
Call for reinspection.

Mac
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Old 07-04-2008, 10:35 AM   #13
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Deck Beam - staggered


"I'm sorry, I'm do not have a lot of faith in this process in it's entirety."

In the first chapter of every building code I have ever read is a disclaimer of liability protecting the building dept. and it's employees. ( what ever happens its not their fault and we can't be held leagally liabel)

Your engineer has liability for his stamped design. They may even carry errors & omission insurance as required by many states.

In many states your lisc contractors are required to carry liability insurance.

your home owners insurance might cover you if you drop a tree on your house, but not if you build the house wrong.

Realize that the purpose of the permit process is for the health and saftey of others. So years from now when your teenage kids have a party for 500 of their near and dear friends on your deck when you are out of town.... they won't end up in a pile on the ground.

I'm glad you got the engr. and the fix won't cost you to much.

Last edited by Big Bob; 07-04-2008 at 10:38 AM.
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Old 07-04-2008, 12:00 PM   #14
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Deck Beam - staggered


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Here's a tip -
Pull all the nails connecting your joists to the beam.
Temp support your joists with a temp beam - push the joists up so they're sitting 1/4" above your current beam.
Pull out that scabbed together piece...
Build a new, properly built-up beam (you can build it in place on the posts if it's too heavy to lift)
MAKE SURE THE BEAM JOINTS ARE DIRECTLY OVER THE POSTS.
Install the new beam.
Pull the temp beam down.
Reaffix the joists to the new, properly built beam.
Call for reinspection.
Good suggestion and thanks. I'll consider that. To help with some of that. with "scabbed together piece" I would use a saw-jaw and the beam right after the post and then cut the beam in the saddle (cutting the nails) then pull the beam out. Replace it with a new beam then pull the temp down. Sounds like a viable manner?

And yes, you read part of that wrong on expectations of the RBD.

But I think you're right, I would be a nightmare customer for a "real deck guy." Case in point, a "real deck" guy that is licensed did a deck for my brother and did some costly things. For instance, he cut into the stucko for the ledger and flashing. That did not need to be done. It was a delay on his part and costly. I confirmed this with my inspector. I was going to do the same but the inspector said not to waste the time and money because since the house is stucko'd do not cut in and flash; one doesn't need to with stucko. In addition, my brother's deck turned out not to be approved because of the hand-rails on the steps; this was done by a licensed contractor. So, fixing that would've been even more additional cost that the license contractor was not going to assume. ticked my brother off. So, all I have are nightmare stories with licensed contractors so you're absolutely right and I will admit I would be a nightmare customer.

At any rate, I appreciate the tip. I'll definitely take that into consideration as well as the fix mentioned by the engineer.

Thanks all for the information.
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Old 07-04-2008, 01:05 PM   #15
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Deck Beam - staggered


Quote:
Originally Posted by BuiltByMAC View Post
Maybe I'm reading this wrong, but if you expect the building dept. to explicitly tell you everything you SHOULDN'T do when building a deck, you expect too much. Common sense would dictate that if a beam is holding up a large weight, the ends of the beam should be supported. Period. That's "Building 101."

Yes, yes, I understand, it's everyone else's fault but yours. You're just young and ill-informed and everyone else needs to look out for your best interests. Give me a break. You want to build a big, elevated deck? Go buy yourself $200 in books (Taunton Press has good stuff), read up on the proper way to build a deck, and educate yourself. I won't even say "Hire a real deck guy" 'cause I get the feeling you'd be a nightmare customer for him...

Here's a tip -
Pull all the nails connecting your joists to the beam.
Temp support your joists with a temp beam - push the joists up so they're sitting 1/4" above your current beam.
Pull out that scabbed together piece...
Build a new, properly built-up beam (you can build it in place on the posts if it's too heavy to lift)
MAKE SURE THE BEAM JOINTS ARE DIRECTLY OVER THE POSTS.
Install the new beam.
Pull the temp beam down.
Reaffix the joists to the new, properly built beam.
Call for reinspection.

Mac
I was thinking of how to word my response (something to do with simple 6th grade physics), and then I read this one, which pretty much sums it up.

Mac's suggestion for replacement of the beam and the methods suggested are spot-on.

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