Installing concrete anchors on large, existing pergola?

[javadog]

Got a picture of the thing?

[Scott Douglas]

Yeah, got a picture?
Does this pergola have a roof that could act like a giant 'sail' if the wind caught it?
If so, I can see the need/desire to anchor it. Our patio 'cover' is only held down with four bolts total, but it's so 'porous' the wind couldn't lift it if it tried.

[red-beard]

I hate drilling concrete. I always seem to hit a piece of aggregate...

[Bill Douglas]

James, I use a rotary hammer drill to drill concrete. It goes straight through aggregate. Ryobi - cheap as chips and goes at concrete like a Rottweiler.

[Scott Douglas]

It's usually the rebar that gets me torqued.

[rwest]

If you go with wedge anchors and I think they are a good choice for this, make sure they are shorter than the thickness of the concrete, drill the hole much deeper than the length of the anchor (don’t want it to bottom out), get the dust out of the hole, put the washer and nut on the top flush, drive it down as far as it goes then tighten the nut.

Lots of people try and drill a perfect depth then put the anchor in the hole and then add the washer and nut- usually it sits too high and you end up with too many threads above ground.

[stomachmonkey]

Originally Posted by biosurfer1

PLEASE tell me you have a good argument that will convince my wife of this

A good argument and one that would convince a wife are two completely different things and at least one of them is a Unicorn.

[cabmandone]

Originally Posted by biosurfer1

PLEASE tell me you have a good argument that will convince my wife of this

Using a hammer drill and setting 24 anchors seemed easier than winning that debate against a non-technical, non-engineer person who only envisions it being blown up in the air and landing directly on my son's bedroom.

Go rent a big fan to put under it pointing up. The say "look honey... it's not budging!" It might work!

[biosurfer1]

Originally Posted by Scott Douglas

Yeah, got a picture?
Does this pergola have a roof that could act like a giant 'sail' if the wind caught it?
If so, I can see the need/desire to anchor it. Our patio 'cover' is only held down with four bolts total, but it's so 'porous' the wind couldn't lift it if it tried.

Yes, it has a roof. I dont have an exact picture, but it pretty much looks like this:




So I suppose it's technically possible it could lift, but I feel like if it's ever that windy, we will probably have bigger problems to deal with.

[908/930]

That has a fair bit of sail area. Not sure what the sail area to weight ratio would be.

[javadog]

Two anchors each of the corner posts ought to do it; if you want to make it symmetrical two anchors at all six…

I have no idea how the roof structure is connected to the posts, that might be an argument for all six.

I would use half-inch anchors.

[Tidybuoy]

Originally Posted by biosurfer1

The post brackets look similar to these:

I used these exact brackets with a fence that I built and installed on top of a concrete patio.

I recommend using expanding concrete anchors. I used 1/2" x 3" and once the hole is drilled (pain btw) I tapped the anchor into the hole and the posts are not going anywhere.

I like the idea above where you are temporarily moving the pergola. However, that may be easier said than done - especially if it is attached to the house. Maybe you could attach some type of 2x4 to the post and use a floor jack to jack up just enough to get the bracket onto the pergola. Then set it back down and drill your holes.

[Baz]

I did not use anchors for mine and it's as solid as a rock.

Drilling holes with the post bracket in place probably means your holes will be drilled at a angle.

[herr_oberst]

Originally Posted by 70SATMan

Even simpler is drilling the same size holes as the bracket without moving anything and then install all thread using concrete epoxy. No need for anchors and they make concrete epoxy that will take the load. That's one method used to install anchors to house foundations that never had them originally.

The permanent solution.
Here's what I'd use to glue the all-thread into the concrete. I've used it before and if you follow all the instructions, especially regarding getting all the dust out of the holes, this will cure harder than the concrete and grip that thread so hard it'll take an act of congress to remove it. I'll bet two fasteners per post would be plenty, too. (set at the diagonal)

[herr_oberst]

Just out of curiosity, is there a good reason that the original builders didn't install fasteners in the first place? I mean, they might as well have just set the end of the post on the ground....

[Baz]

[QUOTE=herr_oberst;11437022]The permanent solution.
grip that thread so hard it'll take an act of congress to remove it.
/QUOTE]

Good advice, but I didn't use any adhesive because at some point I will be removing mine and do not want to make the job any harder than it already will be.

Using an impact wrench is the way to go, BTW.

[dad911]

Remove Trim highlighted above. Add tie down straps, and replace trim to hide.

Hurricane Sandy, my pergola:

[A930Rocket]

Here’s your answer right here.

Baz even brought red heads to the site!

Originally Posted by Baz

I did not use anchors for mine and it's as solid as a rock.

Drilling holes with the post bracket in place probably means your holes will be drilled at a angle.

[Baz]

Originally Posted by A930Rocket

Here’s your answer right here.

Baz even brought red heads to the site!

You bet!

[70SATMan]

Originally Posted by herr_oberst

The permanent solution.
Here's what I'd use to glue the all-thread into the concrete.

We use one of their products and also Hilti when we dissasemble/move our large antennas from one site to another when the customer wants to re-use a foundation.

We don't mess with anchors, they are not as secure. I've seen wedge anchors pulled out before.

If it works with the wind loading of a 13M antenna reflector,,,,,,