Anchoring Pergola to Floating Deck

by Brian Laverdiere
(Foley, MN)

I'm in the process of putting together a floating deck about a foot off the ground as seen at www.deckplans.com (Editor's note: deckplans.com is no longer an active site).

At that site, they are adamant about not recommending attaching a pergola to the floating deck. They recommend poured footings for the pergola and build the floating deck around it - keeping them separate.

This late realized bit of advice spoils the simplicity of my whole plan. Searching for alternate advice has lead me to this site. The Titan Post Anchor seems to be a confident bracket to use. Here are my questions:

Is it sufficient to attach the Titan Post Anchor to deck boards with screws - if so would it be better to drill holes and use bolts, maybe with a back plate instead?

Instead of the above, what if I place the Titan Post Anchor above a joist (or support board between joists) and use "U" bolts or a double plate/long bolt setup, so the posts are actually anchored to the joist instead of just the planks.

Minnesota can get some pretty strong winds, so I thought it would be a good idea to use the auger type tie downs on the deck itself.

If I used the Titan to joist method in the above paragraph, what if the place I pick for the tie-downs are the long brackets securing the Titan anchors to the joists. That way the tie downs are doing double duty - they strap the posts to the ground along with the deck itself.

I guess I'm a bit paranoid from things I've read and want to make sure the next big storm doesn't rip the pergola from the deck or send the whole assembly tumbling across the yard.

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Jul 13, 2011
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Anchoring Pergola to Floating Deck
by: Brian Laverdiere

Thank you very much for posting and answering my question. I also appreciate that you are not stuck on the johnny-one-note answer of don't try to attach the pergola to the floating deck. BTW - My ground is only ever so slightly un-level and I'm not using any posts in the blocks. The joists will sit directly in the slot of the blocks with tiny shims in just a few.

The truth is if we get hit with a tornado we probably have a lot more to worry about then just the deck - they are not as common in my immediate area as straight-line winds, we seem to happen every few years. Mostly we just get windy thunder storms.

So without revamping my whole deck plan, it looks like it comes down to how effectively I can anchor the deck to the ground. I'd love to give your new tie down system a try, but I'm afraid September is too far off for this project. Unless you have an existing tie-downs you can recommend, I'm going to go to my local store and see what they have and probably shoot for an over-kill in anchoring this thing down.

I am wondering if you see any benefit of trying to include the pergola post brackets in the tie down, so that it catches the bracket along with the joist?

Jul 13, 2011
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Pergolas on free standing deck tips
by: Editor-Rich Bergman

There is good reason why they are discouraging you from attaching a pergola to the decking if the deck is built sitting on concrete surface blocks. I will try to fairly cover off as many of the issues as possible.

The concrete block system is great for low level free standing decks that are not situated in wind zone areas - meaning areas that can get tornadoes or hurricanes. Why? Because if the deck goes airborne, so can the blocks and they become canon balls flying through the air.

You can tie the deck down with cables and ground pegs. But then you have the cable wires you have to set into notches in the joist so they don't interfere with the decking over top.

The issue with a pergola on a deck is not the connection to the deck - if done properly. It is with the deck just sitting on concrete blocks with no connection means to the concrete or the ground whatsoever.

This brings me to the pros and cons of the concrete blocks. They are very cheap. $10 each or so. This appeals to many people understandably. But they come with limitations.

The framing structure can be wobbly depending on how it is built in addition to the blocks providing no lateral resistance where the posts set into the blocks.

All of this sets up a scenario where the deck in its entirety is at a higher risk of lifting up in a severe wind storm.

So if you use blocks you will have to tie and anchor the structure down to the deck.

Now, you can certainly build a surface mounted pergola or gazebo on a deck - which is securely anchored to the ground. We have manufacturers of gazebos do that with our product (titan post anchor) all the time and with great unsolicited positive feedback.

But the surfaces they secure to aren't going anywhere. And there is 2x8 blocking underneath the decking boards so the screws have a lot of material to dig into.

You have to build a rigid roof structure that is braced properly to each post. Then you will have an entire structure that is rigid and secure well to the deck surface.

The next issue is affordable ground anchor system.

The Titan Deck Foot which is a new patent pending helical anchor and cap plate system that you can install with a hand held impact wrench. Its a breeze. It would takes thousands of pounds to pull out a single anchor, and probably with a crane. And its lower profile so you can build decks lower to the ground.

Here is a Facebook comment for a customer at the bottom of this page on ground anchors.

That is all I can share in such a short space so for any questions, about pergolas or the Titan Deck Foot call us. 866-577-8868

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