Pergola over existing Deck

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  #1  
Old 03-15-06, 11:28 AM
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Pergola over existing Deck

I have a free-standing deck that butts up against the house but is not attached to it. It is approximately 12' x 15', and is less than 18" off the ground. The main structural support comes from 4x6 beams spaced 6 feet apart, with each supported by four concrete footings.

My wife wants me to build pergola over this deck.

Is it possible to attach the posts for the pergola directly to the support beams of the deck? Or do I need to dig separate footings for each of the pergola's support posts? I am guessing the latter, but I was hoping to avoid dismantling the deck if at all possible. I was planning to use 6 6x6 posts as the vertical members, with 2x8 beams and 2x6 rafters.

Thanks
 
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Old 03-15-06, 03:12 PM
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clifft,

You've got some work ahead of you.

You need footings for the pergola, no way around it. Pull off enough deck boards so that you can dig the footings. Place the posts between the joists and girders of the deck. If it's a wood pergola, use sonotubes and set Simpson CB's or CBSQ's for the wood posts to rest in. If it's aluminum (with steel posts) or vinyl, you can embed the posts in the wet concrete of the footings.
 
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Old 03-16-06, 07:19 AM
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Lefty:

Thanks for the advice. Looks like I do have some work ahead of me.
 
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Old 03-20-06, 05:09 AM
deckgrasshopper
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Vinyl products are pretty light

Are you positive he would have to dig new footings? If he were to attach a ledger to the house for the pergola and run it out to his 6x6's which were attched to a well supported beam - he should be OK if he uses vinyl even with the steel inserts.

For that size - I would use 4x4's and buy thesee 5x5 vinyl sleeves that slip over them. Then use your 2x8 (with wood slipped inside) as the main beam. The 2x6 rafters (at 15') probably need the steel inserts which aren't that heavy.

It sounds like your deck is well supported and should be able to handle the weight. Particluarly if you attach the posts to your beam.

There is no question cement footings would be the stronger way to go....but is it overkill?

That's my two cents.....


PS- can anyone suggest where to buy vinyl pieces like that?
 
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Old 03-20-06, 12:00 PM
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deckgrasshopper,

It has nothing to do with the deadload weight of the vinyl pergola -- it's all about the wind load and keeping it upright, keeping it from tearing the deck apart, and whatever snow load that clifft might need to meet to keep it from sinking into the ground or being collapsed. If it were being attached to a concrete slab, they clifft MIGHT be able to do it without footings. But he's not going to be able to attach it to a free-standing deck that wasn't designed with the pergola in mind. Ledgering it to the house, either with a ledger attached to the wall or one that is attached to the roof with 1/8" X 1" X 8" or 10" angle brackets over every rafter or every other rafter would probably be fine. I do that all the time, and it eliminates having to make the pergola free-standing. But he'll still need footings under the outside beam.
 
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Old 03-23-06, 01:33 AM
deckgrasshopper
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Building a deck with a pergola in mind

OK - I'll bite.

I'm building a deck and want to build it with a pergola in mind. The deck will be attached to the house via a ledger board. The future pergola will also be attached to the house.

The part of the deck that will have the pergola is 16x16 square with corners cut off (2x2 triangles). I haven't decided how big the pergola will be, but for this discussion - lets say 16' wide and 14' deep. The deck will be composite - with standard stats 2x10 joists 16" OC with a double 2x10 beam on cement footings.

One way to prepare would be to put cement footings in now where the 3 pergola posts will be. That's a sure thing, but going to be extra work.

The other is to assume I can fix the pergola posts to the deck framing as I would the railing. Will that meet code for the wind shear you are talking about? (both deck and pergola attached to house)

Obviously, its easier to build the pergola - then the deck - but these vinyl pergola's run nearly as much as the deck will (kits) - so I can only afford to do one this year. And it won't be the pergola.

The PA code (as far as I can tell) does not have much to say about how to do this.

Thanks for this topic....
 
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Old 03-23-06, 05:20 AM
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deckgrasshopper,

It's all in the planning.

Pour the pergola footings before you build the deck, and have them inside of the deck beam -- closer to the house than the deck beam. Lay out the deck joists so that none are in the way of getting to the pergola footings. Install the anchors in the pergola footings. The more you can do before you build the deck, the easier it will be next year when it's time to build the pergola.
 
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Old 03-23-06, 07:40 AM
deckgrasshopper
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Thank you

Lefty-

Thank you for your time and info. Clearly, the best path for me is to dig the footings. now and access them later.

I did have one idea however that could help others with an existing attached deck - if you have a cantilevered beam - why can't you just remove the deck boards above the beam, and drop your 4x4's for the pergola posts on top of the beam and use those post beam brackets. That way you get the cement footing through the beam and you get a pergola that runs most of the way out your deck.

Also allows for variable widths.....

Thanks again -
 
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Old 03-23-06, 07:28 PM
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It would probably work out just fine, but I can't do it that way. I'm in siesmic zone 4. (L.A. or 'Frisco has an earthquake and I have to pay the price... but that's another story!!) Around here, the pergola has to have it's own seperate footings.
 
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