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Old 03-22-2012, 04:56 AM   #1
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Notching 6 x 6's at two separate heights


Hello,

I am replacing a 30 year old 8 x 32 deck with a new one as per the attached detail. Some explanations:

1. Deck posts will be 6 x 6 x 16 spaced 10'-8" O.C. set at 7'-6" from the wall ledger. Beam will be 2-2 x 10 notched into the 6 x 6 at 93 inches above the concrete walk out original to the house. I am planning for a 2'-6" canteliever, as shown, for a total depth of 10' - 0".

2. Joists will be 2 x 6 x 10 spaced 12" O.C. and joist hung with Simpson U26's at the ledger and the rim joist (2 x 12). I want to run the decking perpendicular to the house so, I am adding 2 x 4 Runners perpendicular to the 2 x 6's and will be strong tying them with Simpson H-1's every other 2 x 6 joist. 2 x 4 runners spaced 24" O.C. except for the canteliever, which will be 23". As non standard as this appears, it actually makes for a solid decking surface as my original deck was constructed similarly with 2 x 6's attached to either side of the 4 x 4 posts and the runners attached with nothng more than toenailing. No other joisting was used.

3. I want to cover this deck ( as soon as I figure a way to avoid a 2/12 pitch, or less, situation) eventually so, I was planning on notching the 6 x 6's at 93 inches high for the doubled up 2 x 10 beam supporting the main deck and then again at the planned roof height for 2 - 2 x 6's to support the ceiling joists and rafters. Both of those will be 2 x 6.

Question #1 - Is this OK? Just looking at it makes me a bit leery. Perhaps I am overthinking it, but.....I want to keep the number of posts to the minimum and I really really don't want to buy 8 x 8's at $130.xx a pop.

Question #2 - Does anyone see any glaring no-no's in the detail? I have researched the spans and sizes and all are within code.

My apologies. The upload is quite fuzzy. I will see if I can sharpen it up. Thank you very much for your time and comments.

EDIT: I added it as an attachment and it is much clearer. Link at the bottom. Thanks again!

Attached Thumbnails
Notching 6 x 6's at two separate heights-deck-canteliever-detail1.jpg  

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Old 03-22-2012, 06:00 AM   #2
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Notching 6 x 6's at two separate heights


I can't see enough detail of your attached dwg.....

8x8? I'm assuming you think you need to go to that if the 6x6 is not large enough????????????

Regarding spans....don't be afraid to go LVL or PSL over sawn lumber. Lots of advantages.

Now...with all that said...be ready for the "do you have permits and engineering?" responses. I agree with that to some extent....especially when your doing work in your house....outside? Some slack...where safety is concerned? Do it right....

One last note....most span tables you come across are minimum specs....marginal at best to keep it safe....

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Old 03-22-2012, 06:43 AM   #3
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Notching 6 x 6's at two separate heights


The IRC deck code 2006 edition only allows up to 14 foot high posts (R407). This is probably because of potential buckling issues. I don't know if subsequent editions revised the maximum height upwards. I would run the buckling analysis for your posts. This is a little complicated because of the notching, so you do not have a uniform section. The vertical load is also not uniform, since you pick up deck load at approximately the midpoint, and of course roof load at the top. You also have to account for lateral loading during a wind storm. I don't think you are going to find any tables for this complex load condition, but maybe the building inspector has some experience with this type of construction.
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Old 03-22-2012, 07:36 AM   #4
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Notching 6 x 6's at two separate heights


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Originally Posted by ddawg16 View Post
I can't see enough detail of your attached dwg.....

8x8? I'm assuming you think you need to go to that if the 6x6 is not large enough????????????

Regarding spans....don't be afraid to go LVL or PSL over sawn lumber. Lots of advantages.

Now...with all that said...be ready for the "do you have permits and engineering?" responses. I agree with that to some extent....especially when your doing work in your house....outside? Some slack...where safety is concerned? Do it right....

One last note....most span tables you come across are minimum specs....marginal at best to keep it safe....

What concerns me is that notching for 2 - 2 x10's (3") will only leave me with 2 1/2" left. If the post ended there, no problem. I would think that would be a potential weak spot especially seeing as how I want to continue the same posts up to support the roof extension. I am trying to keep the number of posts at a minimum to maintain the lakeview. I have no question about the 6 x's being being more than stout enough, without the notches.

Span Tables - Yeah, I wish to get as solid as I can and do the minimum as far as anti-sway measures. The original had those stupid Y-braces which I abhor. If I wasn't set on cantelievering the last 30", I would consider dropping one of the 6 x's and just going with 3 total.

Permits - Back in the late 90's, I ventured down to the county to talk about permits and codes. Was told with a quizical look, "Uhhhh, I guess that's up to your Homeowner Association." This is rural Southern Illinois. Johnson County, Lake of Egypt. As I saw more of the local building examples, I understand.

Thanks!
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Old 03-22-2012, 07:51 AM   #5
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Notching 6 x 6's at two separate heights


Quote:
Originally Posted by Daniel Holzman View Post
The IRC deck code 2006 edition only allows up to 14 foot high posts (R407). This is probably because of potential buckling issues. I don't know if subsequent editions revised the maximum height upwards. I would run the buckling analysis for your posts. This is a little complicated because of the notching, so you do not have a uniform section. The vertical load is also not uniform, since you pick up deck load at approximately the midpoint, and of course roof load at the top. You also have to account for lateral loading during a wind storm. I don't think you are going to find any tables for this complex load condition, but maybe the building inspector has some experience with this type of construction.

Yeah, I figured I would be pushing the max at 16 feet and the notching would have to lessen that. Good call on the wind shearing. That side of the house (lakeside) gets all the weather (out of the west/southwest). This is the main reason I want a roof extension. It's beating that side of the house up. My patio doors are on set number three since '82 (Built in 82). Plus, the sun can be kind of brutal. Agreed, I need to run this past an engineer, if I can find one down here. Seriously, getting code determinations here is like dealing with Sam Drucker and Mr. Haney from Green Acres.

The buckling issue. The more I look at this, the more I agree with you. It may never happen, but 2 1/2 inches material remaining, blocked at the joists or not, seems real iffy. Thanks for the confirmation. My best probable solution is to start new posts supported directly on the beam and blocked and lagged into the joists every 8 feet.

Thanks, man!
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Old 03-22-2012, 09:33 AM   #6
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Notching 6 x 6's at two separate heights


I've got a project with 3 notches in a 6x6 post, one for a flush deck beam, one for a dropped deck beam, and the top is notched for a roof... No problems there (BTW engineer stamped). I however don't like your framing plan, I don't like the 2x4's to change the direction, and I don't like the 2x6 joists. What kind of decking are you planning on installing?
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Old 03-22-2012, 02:44 PM   #7
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Notching 6 x 6's at two separate heights


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Originally Posted by robertcdf View Post
I've got a project with 3 notches in a 6x6 post, one for a flush deck beam, one for a dropped deck beam, and the top is notched for a roof... No problems there (BTW engineer stamped). I however don't like your framing plan, I don't like the 2x4's to change the direction, and I don't like the 2x6 joists. What kind of decking are you planning on installing?

Robert, I am planning for 5/4 x 6 pressure treated. The 2 x 4's running perpendicular to the joists, are to run the decking perpendicular to the house. I was trying to avoid diagonal decking or running parallel to the house with butt joints. I am assuming the flush beam notch you did was for 2 -2 x's? Hmmmm...OK, good to know. Yeah, the 2 x 6's seemed undersized to me at first also. They are well within total span @ 12 O.C. so I figured an unsupported span of 7' - 6" was solid. You recommend jumping up to a 2 x 8?

I could do seam boards at the posts and then deck parallel into them, I suppose.

Last edited by 98ZJUSMC; 03-22-2012 at 03:24 PM.
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Old 03-22-2012, 04:08 PM   #8
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Notching 6 x 6's at two separate heights


Quote:
Originally Posted by 98ZJUSMC View Post
Robert, I am planning for 5/4 x 6 pressure treated. The 2 x 4's running perpendicular to the joists, are to run the decking perpendicular to the house. I was trying to avoid diagonal decking or running parallel to the house with butt joints. I am assuming the flush beam notch you did was for 2 -2 x's? Hmmmm...OK, good to know. Yeah, the 2 x 6's seemed undersized to me at first also. They are well within total span @ 12 O.C. so I figured an unsupported span of 7' - 6" was solid. You recommend jumping up to a 2 x 8?

I could do seam boards at the posts and then deck parallel into them, I suppose.
It was actually for our steel frame system that we build all of our decks out of the beams were ea 2.25" wide, the top was notched for LVL beams.

5/4 x 6 spanning 24" O.C. is not a good idea (your 2x4's are now the joist span for the decking) I would rather do diagonal decking than to do that detail. Another option is to turn your beams so they go from house to edge of deck, then hang joists in between them, then you can lay your decking the other way. 2x8 would be the smallest wood frame I would use.
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Old 03-22-2012, 08:55 PM   #9
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Notching 6 x 6's at two separate heights


ive notched 6x6's in the past for deck beams.. however we didnt let in both ply's only one ply gets let in the other gets nailed flush. its still just as strong as long as they are properly laminated with the correct nailing pattern. it also ensures your decking is supported on its edges where its notched for going around the posts.

my only concern is the spacing of your posts 10'8" is too much for only a 2ply beam. i would reduce the spacing down to 7' but check with the local building authorities first

i have photos of one such deck. just cant find them at the moment.. ill have to dig them out otherwise then scan them
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Old 03-22-2012, 10:43 PM   #10
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Notching 6 x 6's at two separate heights


Quote:
Originally Posted by robertcdf View Post
It was actually for our steel frame system that we build all of our decks out of the beams were ea 2.25" wide, the top was notched for LVL beams.

5/4 x 6 spanning 24" O.C. is not a good idea (your 2x4's are now the joist span for the decking) I would rather do diagonal decking than to do that detail. Another option is to turn your beams so they go from house to edge of deck, then hang joists in between them, then you can lay your decking the other way. 2x8 would be the smallest wood frame I would use.
Quote:
(your 2x4's are now the joist span for the decking)
You're right and I was considering that when I decided to space the 2 x 6's on 12" centers.


Quote:
Another option is to turn your beams so they go from house to edge of deck, then hang joists in between them, then you can lay your decking the other way
I resisted that option at first, but I think you may be right. Alternatively, I have been looking harder at diagonal decking it. It would solve any sway issues.

Thank you, sir.

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