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Old 10-13-2010, 06:02 PM   #1
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18 x 17 Free Standing Overhang


Hello everyone, I'm new here and would very much appreciate any and all advice.

I built an 18 foot by 17 foot patio roof with 6x6 posts, 6x12 headers, Simpson Post Caps, 5/8 plywood decking. Simpson anchors in footings were poured when the patio was poured. They have a 1 inch lift to avoid wood rot.

I didn't attach it to the house, reason being is the stucco is brand new, and I didn't want to cut into it and risk leaks. So I built the overhang 1/4 inch from the house.

The issue I have is when I pull and push on it, it has a little bit of racking left to right. It doesn't really give from back to front. The achors were all installed with the flanges going the same direction, so I'm wondering if that has anything to do with why I get the left to right racking. I installed 2 x 6 corner bracing with nails which helped a little bit, but I'm thinking that I need to beef them up to possibly 6x6 and use screws?? When I push and pull back and forth, I can hear and feel the corner braces both squeeking and budging.

Do you guys think beefing up the corner braces and using heavier duty screws or bolts will help? If so, what length and size would you recommend for the wood and what size scews/bolts?

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Last edited by tuffloud1; 10-17-2010 at 09:03 PM.
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Old 10-13-2010, 09:25 PM   #2
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18 x 17 Free Standing Overhang


Tuff,
I don't think you did anything wrong here. Looks like a pretty nice structure. The fact that you have a substantial roof on just the four posts without attachment to the house is going to produce a little flex. If you attached it to the house on each side in the upper portion, you would more than likely eliminate just about all the movement. Without having any sidewall sheeting to solidify things, a certain amount of movement is bound to happen.
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Old 10-13-2010, 09:45 PM   #3
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18 x 17 Free Standing Overhang


I agree, very nice construction. The techniques you used are appropriate for an outside uninhabited structure, for a house you would want greater shear resistance, which would generally be provided by the sheathing on the house. Obviously there is no sheathing here, so the majority of lateral resistance is provided by the post attachments, the diagonal bracing, and the collar ties in the roof.

Since you don't provide a location, I have no idea what the wind loads in your area are. You may want to consider installation of hurricane clips to keep the roof on, if you have not installed them, I couldn't tell from the photos. Part of the reason you have left to right sway is that there are no rafter ties, since there are no floor joists, and the collar ties provide only limited lateral stability. Again, not a problem for an outside structure, assuming your building inspector did not complain.

You could bolt the diagonal bracing in place, that is typically how decks are done, but if you want to maximize lateral bracing, use at least four half inch bolts per member (two on each end), preferably six bolts per member, else the diagonal brace can rotate around the bolt, negating the lateral resistance.
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Old 10-13-2010, 11:42 PM   #4
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18 x 17 Free Standing Overhang


you might consider 'let in' braces which, IMHO, would help tighten the frame.
they would still need to be bolted, of course.
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Old 10-14-2010, 12:09 AM   #5
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18 x 17 Free Standing Overhang


In the pictures there are no corner bracings on the side adjacent to the house. This is the main reason for the movement parallel to the house wall and why there is no noticeable movement toward the wall since you have corner bracings on both sides of the roof in that direction.

If after you add the missing bracings there is still movement then you need to relocate all bracings further down on the post at one end and further away horizontally on the header at the other end. You cannot reuse the current bracings because they are too short for this, you will need new longer ones.

Another necessary improvement is adding horizontal/diagonal braces at the corners between headers to resist horizontal rotation/twisting of the entire structure.

Putting in more fasteners as it has been suggested won't solve the problem, but the wind clips are a good idea.

Such a structure open on 4 sides is a Post and Beam type and the best way to brace it is to embed the posts (PT) several feet into the ground resting on a concrete footing down below and then you would not need all the bracings discussed here, but you already have what you have so let's try to make the best out of it.
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Old 10-14-2010, 12:34 AM   #6
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18 x 17 Free Standing Overhang


Thanks a lot for the input guys, glad I didn't fail!

I live in the Sacramento area .We have great weather here with an occasional bad storm during winter.

I went and bought some 6x6 to upgrade the corner braces to match the 6x6 posts. I'll put one 1/2 inch by 8 inch galvanized lag screw in each end of each corner brace and counter sink it with a washer.

More than one seems like too much because I already have to offset the bottom screw of each brace as to not run into the other one coming in from the other side of the post.

I would imagine this would dramatically improve the left to right sway from the current 2x6 corner bracing with only nails that is currently in place.

What do you guys think?

Also, what are 'let in braces'?

Thanks again!

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Old 10-14-2010, 01:48 AM   #7
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WARNING!

Don't do let in braces!

They cut into the thickness of the posts to insert them and this will create a "hinge" or weak point that in this case will eventually lead to collapse.

Read my earlier comments on the missing bracings.
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Old 10-14-2010, 09:57 AM   #8
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I prefer 1/2 inch diameter galvanized through bolts with washers on each side over lag bolts. Deck code does not allow lag bolts for connecting beams to columns, and shows 3/8 inch diameter through bolts for diagonal bracing. You have a heavier structure than a typical deck, so 1/2 inch bolts would be appropriate. Not sure what code your structure falls under, but deck code would be a reasonable starting point if there is no specific code for your structure type.

The diagonal braces do not need to be 6x6, they can be 2x6, but as noted by previous poster the longer the brace the better the lateral stability.
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Old 10-14-2010, 10:55 AM   #9
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18 x 17 Free Standing Overhang


It looks lovely. It is REALLY impressive if it has a building permit seal of approval. Whatever you do next, if anything, is your code officer in on the plan?
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Old 10-14-2010, 11:43 AM   #10
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18 x 17 Free Standing Overhang


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Originally Posted by Daniel Holzman View Post
I prefer 1/2 inch diameter galvanized through bolts with washers on each side over lag bolts. Deck code does not allow lag bolts for connecting beams to columns, and shows 3/8 inch diameter through bolts for diagonal bracing. You have a heavier structure than a typical deck, so 1/2 inch bolts would be appropriate. Not sure what code your structure falls under, but deck code would be a reasonable starting point if there is no specific code for your structure type.

The diagonal braces do not need to be 6x6, they can be 2x6, but as noted by previous poster the longer the brace the better the lateral stability.
The 6x6 braces won't hurt anything though right? I like the look of it because it matches the posts in size.

When you say bolts, do you mean drill the hole all the way through both the brace and post and counter sink the post side and brace side to make each end of the bolt flush?

Also, I can't get bolts all the way through the 6x12 header obviously, so I would have to use lag screws up there, right?

The other thing is, if I used 2x6 for the bracing, that would be pretty difficult to impossible to put a bolt through that. This is the reason I bought 6x6 is to make it easy to get that 1/2 inch lag screw through. The scews I bought go almost all the way through just shy if dimpling out the other side of the post.

Will the 1/2 inch lag screws hurt anything structuraly?

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Old 10-14-2010, 12:47 PM   #11
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Tuff, your 2x6’s would go to the outside of your post and lap over the side of the post and beam then bolted though.
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Old 10-14-2010, 01:03 PM   #12
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Tuff, your 2x6ís would go to the outside of your post and lap over the side of the post and beam then bolted though.

Light bulb goes on..... Thanks man, you are a life saver.

I'll go longer on the 2x6, lets say 4 feet, and I'll drill a hole all the way through the brace and header/post and put a bolt in.

Do I just offset the holes on the bottom end of each brace on the same post? Otherwise each bolt will run into each other right?
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Old 10-14-2010, 01:08 PM   #13
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Do I just offset the holes on the bottom end of each brace on the same post? Otherwise each bolt will run into each other right?
Correct.

The longer the brace the better. Go as low as you can without creating a headache.
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Old 10-14-2010, 01:13 PM   #14
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Go as low as you can without creating a headache.
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Old 10-14-2010, 01:22 PM   #15
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18 x 17 Free Standing Overhang


Last night, I installed one of the lag screws into one of the posts with the 6x6. Now that I'm going with the 2x6 on the outside of the headers and posts instead, and I'm removing that one screw that goes throught the 6x6 brace into the post, will the hole hurt the integrity of the post?

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