# Pergola shaky and wobbly, need help.



## mark sr (Jun 13, 2017)

If the 45° angle braces were longer and further down the post that would help .... but I'm just a painter, the carpenters should be along later.


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## SeniorSitizen (Sep 10, 2012)

Cables with turnbuckles.


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## Nealtw (Jun 22, 2017)

Everyone is a designer what could go wrong?

The question now is what forces are you dealing with and what to do about it.

The easy one to start with is put plywood under the metal roof. that will stop the structure from racking.

The angle braces only look after the racking in one direction, but they do not stop the racking or the bend factor. So the posts might need a better tie down that will also deal wit some of that and maybe only a few posts need help.

Maybe something like this for the post
https://www.strongtie.com/sdsscrewholdowns_holdowns/hdc_holdown/p/hdc

Simpson's make a pile of stuff for tie downs.


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## abrowning (Jun 2, 2008)

How about a closeup where the post ties in to the two double beams? Knee braces aren't going to help if those connections aren't solid.


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## jlhaslip (Dec 31, 2009)

Couple of things which cross my mind and have not been addresses above.

The connection of the beams to the braces show only a single bolt. I would've used pairs of bolts. Singles act like a hinge point and doubling them removes some of that. Ditto for the connections at the posts.

The connection of the braces to the post. How are they connected? Nailed? My preference would be to drill through the tail ends such that a bolt or readi-rod can connect the bottoms of both / opposing braces and the posts. The bolts can also be tightened as the material shrinks with drying.


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## avgjoeblack (Jul 27, 2017)

abrowning said:


> How about a closeup where the post ties in to the two double beams? Knee braces aren't going to help if those connections aren't solid.


Hope this helps.


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## avgjoeblack (Jul 27, 2017)

jlhaslip said:


> Couple of things which cross my mind and have not been addresses above.
> 
> The connection of the beams to the braces show only a single bolt. I would've used pairs of bolts. Singles act like a hinge point and doubling them removes some of that. Ditto for the connections at the posts.
> 
> The connection of the braces to the post. How are they connected? Nailed? My preference would be to drill through the tail ends such that a bolt or readi-rod can connect the bottoms of both / opposing braces and the posts. The bolts can also be tightened as the material shrinks with drying.



Yeah, it's only a single bolt for the beams as I saw others do it that way. For the 45 degree, I used 6 inch lag bolts into the post. Yeah, hopefully the 2 bolts will solve my issue. That will be a quick fix. Other thing to point out is my braced corner rafters holding the beams together are only toe nailed, not bolted through like the beam. Reason was I tried to maximize the height. 

I was thinking of bolting a 2x6 perpendicular to the beams/headers. Would that help. It feels like most of the wiggle is from the posts concrete brackets.


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## avgjoeblack (Jul 27, 2017)

Would that add more weight to the structure? How would I approach it? It will definitely help. It feels like I'm almost there, just need a little of stability. 



Nealtw said:


> Everyone is a designer what could go wrong?
> 
> The question now is what forces are you dealing with and what to do about it.
> 
> ...


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## Nealtw (Jun 22, 2017)

The single bolt could be a problem but it would also show up in some movement of the angle cut at the post. As they still look tight that is not the problem. But with out a fix that could be symptom in the future


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## avgjoeblack (Jul 27, 2017)

Nealtw said:


> The single bolt could be a problem but it would also show up in some movement of the angle cut at the post. As they still look tight that is not the problem. But with out a fix that could be symptom in the future


I would have to run to the store to get the bolts as I'm out. Really hoping that will work. Would adding a 2x6 on each side to my 12ft depth help?

For example, adding it right below those 2x8's.


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## SeniorSitizen (Sep 10, 2012)

You have already identified the major problem by comparing to your friend's construction and it's at the ground connection with the simpson type ties. Modifying the upper will be futile.


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## Nealtw (Jun 22, 2017)

They make all kinds for seismic tie down.
You could get some the stand beside the post, bolt to the concrete and have 30 nails in the post.
https://www.strongtie.com/sdsscrewholdowns_holdowns/hdq_holdown/p/hdq.hhdq

But even with that you will have some bending a racking.


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## avgjoeblack (Jul 27, 2017)

Nealtw said:


> They make all kinds for seismic tie down.
> You could get some the stand beside the post, bolt to the concrete and have 30 nails in the post.
> https://www.strongtie.com/sdsscrewholdowns_holdowns/hdq_holdown/p/hdq.hhdq
> 
> But even with that you will have some bending a racking.


Yeah, I don't mind if it's minor racking. But mines feel like it just needs some sort of tuning/tighten up to get it stable. 

Like Seniorcitizen says, fixing the top may be futile. But I will try the bolt idea first and see what happens since it's the easiest and cheapest.


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## avgjoeblack (Jul 27, 2017)

SeniorSitizen said:


> You have already identified the major problem by comparing to your friend's construction and it's at the ground connection with the simpson type ties. Modifying the upper will be futile.


Yeah, say it ain't so. I always felt it would stand on it's own like a table but I guess not. Maybe 3 feet deep next time I build another one.


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## Nealtw (Jun 22, 2017)

avgjoeblack said:


> I would have to run to the store to get the bolts as I'm out. Really hoping that will work. Would adding a 2x6 on each side to my 12ft depth help?
> 
> For example, adding it right below those 2x8's.


I Would not do anything up top before you stabilize the post if they stabilize.

Find a problem before you fix it. If you can see movement between two members then see what would stop that movement.


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## avgjoeblack (Jul 27, 2017)

Nealtw said:


> I Would not do anything up top before you stabilize the post if they stabilize.
> 
> Find a problem before you fix it. If you can see movement between two members then see what would stop that movement.



Thanks, I will see which bracket is best for stabilizing the posts.


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## Nealtw (Jun 22, 2017)

avgjoeblack said:


> Thanks, I will see which bracket is best for stabilizing the posts.


I used to be able to find things on line but now they have made it easier.:vs_mad:


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## techboomie (Jul 28, 2017)

hope you get this fixed i hate shaky and wobbly stuff


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## Daniel Holzman (Mar 10, 2009)

There is nothing wrong with the post brackets, they are correctly installed. Post brackets are not designed to resist moment (rotation), the are intended to resist lateral movement only. Decks are built exactly the same way, the deck posts are attached to metal brackets, and the posts are allowed to rotate in the brackets.

The method used to stabilize a deck is to use diagonal bracing, and you can do exactly the same thing. In fact, you have some diagonal braces, the problem is that they are not long enough. In one previous post, there was a suggestion to use diagonal wires stretched between the bottom of one post and the top of the next one. This is a good, workable alternative, and will stiffen the structure. You may not like the appearance, so an alternative is to use long wood diagonal braces between posts.

If you don't want to use long braces, an option is to bury the posts in the ground, typically surrounded by concrete. This converts the posts into moment resisting posts, and if you embed the posts deep enough, you will get enough resistance to rotation to stiffen the structure. This is how pole barns are built. The problem is that the posts tend to rot underground after ten years or so, but if you use enough preservative on the wood, they can last longer. I have examined some pole barns that used creosote preserved posts, and have lasted 50 years.

If it were my pergola, I would go with the long diagonal braces.


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## abrowning (Jun 2, 2008)

Nealtw said:


> I Would not do anything up top before you stabilize the post if they stabilize.
> 
> 
> 
> Find a problem before you fix it. If you can see movement between two members then see what would stop that movement.




I agree with the second paragraph. You say it's wobbly so there must be some joints opening up on top when you lean on it. Get your head up there while someone leans on it and see which ones open. Even a small deflection amounts to a very noticeable wobble over eight feet of post. 

You might need to double up fasteners and retighten bolts a few times - as the wood dries out it shrinks and the bolts go slack. A single bolt connection that is slack is basically a hinge.


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## avgjoeblack (Jul 27, 2017)

Daniel Holzman said:


> There is nothing wrong with the post brackets, they are correctly installed. Post brackets are not designed to resist moment (rotation), the are intended to resist lateral movement only. Decks are built exactly the same way, the deck posts are attached to metal brackets, and the posts are allowed to rotate in the brackets.
> 
> The method used to stabilize a deck is to use diagonal bracing, and you can do exactly the same thing. In fact, you have some diagonal braces, the problem is that they are not long enough. In one previous post, there was a suggestion to use diagonal wires stretched between the bottom of one post and the top of the next one. This is a good, workable alternative, and will stiffen the structure. You may not like the appearance, so an alternative is to use long wood diagonal braces between posts.
> 
> ...


Diagonal braces won't be an option because I need the space. As far as the braces length go, is there a general rule like 1/3 or something? I do feel it, longer would stabilize it more like a table top.

But as far as the post brackets go, thanks for reiteration. I really felt like it had to be rock solid. I guess not.


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## avgjoeblack (Jul 27, 2017)

abrowning said:


> I agree with the second paragraph. You say it's wobbly so there must be some joints opening up on top when you lean on it. Get your head up there while someone leans on it and see which ones open. Even a small deflection amounts to a very noticeable wobble over eight feet of post.
> 
> You might need to double up fasteners and retighten bolts a few times - as the wood dries out it shrinks and the bolts go slack. A single bolt connection that is slack is basically a hinge.


I'm definitely gonna try it tomorrow with the bolts, it's cheap and fast. See how it goes. Then extend longer braces.


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## avgjoeblack (Jul 27, 2017)

You guys are awesome, keep the tips coming. I will keep you updated on what happens tomorrow.


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## abrowning (Jun 2, 2008)

While I'm brainstorming. What about heavy duty steel angle brackets? Not light gauge steel like the Simpson stuff you get at Home Depot. Like 1/2" steel with each leg being at least 8"? I'm certain I've seen things like that on structures in my local park. Also, I know they make heavy brackets to simulate timber frame construction construction without all that pesky mortising so the hardware is out there but you won't find it at a big box store.


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## ZTMAN (Feb 19, 2015)

Re-read post number 20. I would trust Dan's opinion


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## SPS-1 (Oct 21, 2008)

If you don't want to make the diagonal braces longer, you may be able to make them more rigid. If you put a 3/16" thick steel plate to tie in the post to the two braces that should stiffen it up. Paint it a gloss black and a lot of people would say it looks fine. Possibly you don't have the resources to make those plates yourself, but you could make a template out of hardboard and take it to a sheet metal or fab shop to cut it on bandsaw or manual plasma cutter. 

Could put steel at upper connections too, but that could be harder. I think it would look better if the plate were sunk into the 4x4 brace and in-between the 2 x 10's. Try the lower gusset only first, and see how much improvement.


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## abrowning (Jun 2, 2008)

ZTMAN said:


> Re-read post number 20. I would trust Dan's opinion




The post brackets he is talking about are post BASE brackets. And I agree completely with what he said about them. The brackets I'm talking about are used in post to beam connections.


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## navyaj (10 mo ago)

So what ended uo being your fix?


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## b.rooster4321 (Apr 22, 2020)

Five year old thread


Sent from my iPhone using Tapatalk


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