All Replies on Planning to Build a Pergola on a existing deck but I don't know how to attach the posts.

I’ve built decks with pergolas (see project 65103), but I built the deck and the pergola at the same time. Those post run through the deck and attach to concrete pylons below. Very sturdy.

Adding a pergola to an existing deck is, IMO, more challenging. I’ve never done it.

FWIW – Here is what I think I would do – -

The first question is if the post from the ground up to the deck are in the same position as the posts you want to run from the deck up for the pergola. If the are, great. If not, I would build some solid framing under the deck so you have something solid to work from.

I’d get an extra long drill bit and drill a hole straight down into the post or framing below. I’d also drill a hole into the bottom of your new posts. Then I drive a steal rod or a hardwood dowel hole below and mount the post over the dowel or steal rod.

So far, I have only described the approach and I have not commented on sizes or materials. I think steal is better than wood, long is better than short and thick is better than thin. You can decide how strong you need to make it. A key factor is how much wind it will be subjected and how rigid the top will be.

As a bench mark, I would probably go 12” down, 12” up and us a 3/4 steel rod – but I over do everything.

Perhaps the most important aspect of this project is getting those holes in the deck and post or framing below perfectly vertical. I would probably build a jig to help me keep the drill vertical.

-- Rich, Cedar Rapids, IA - I'm a woodworker. I don't create beauty, I reveal it.

Some pics of the existing deck would help. From above and below if you can where you want to put the pergola.

-- In the end, when your life flashes before your eyes, will you like what you see?

I’d tear the deck up, dig holes for the posts, use 2 part poly urethane for the posts,
set the posts plumb etc, and then re-deck it.

rmiz24 if your pergola is not attached to a solid structure.(such as a house). Than you need to run your posts through the deck and attached to piers or solid concrete.Also place them either next to a rim joist or beam structure. Then you are able to solid block them also between joists. This also gives you the backing to re-attach your decking. I know it sounds like over kill but most pergolas are not designed for lateral stress. Which makes it easy for wind to get them moving. I hope you have a enjoyable time with your project. I also look forward to seeing it here when you finish!!!!!!

-- The best and most beautiful things in the world cannot be seen or even touched. They must be felt with the heart. "Helen Keller"

Thank you guys for the replies. I will probably get pictures tomorrow morning. I just sketched this drawing(sorry messy, i drew it with a cast on) so I can show you guys where its gonna be located. Im not sure if Im gonna keep it like how it is or just make it 4 side rectangle. I “circled” and “squared” the part where posts need to be and i wanna know how each should be secured. Im guessing/hoping I can just replace the “circled” area with 8ft posts for the 4×4 attached there already(for the fence around the perm. of the deck. for “squared” posts, I would probaly hve to dig a hole there and concrete it like a footer?

I build a lot of decks,deck covers and pergolas. I would make sure your post are in the ground at least 30” or more depending on the height of the pergola ,with a concrete pad under the post before you poor concrete around them. If you don’t want to disturb your deck just put the post out side of the deck.the rest of the details will depend on your design. What ever you do don’t just connect your post to the top of the deck.

-- W James Brokenbourgh Custom furniture maker http://artisticwoodstudio.com/

So I feel like the best or probably the only option is to dig a hole and cement it. but with the joists in the way, how would I dig that hole? can I do this by hand(preferably)

You will have to remove some decking and may be cut out a part of the joist and reinstall them to get the job done

-- W James Brokenbourgh Custom furniture maker http://artisticwoodstudio.com/

I have been searching for some stuff online and I hear that putting posts in cement underground causes the post to rot very fast. I wanna know how to have a sturdy post and have it not rot?

rimz24, you can purchase a post base that has a pipe going into the concrete. You mount your post in the base above the concrete. Here are a couple examples: http://www.strongtie.com/products/connectors/pb-pbs.asp
and http://www.strongtie.com/products/connectors/epb44t.asp

-- Darrell, making more sawdust than I know what to do with

2 part poly urethane

http://www.graservices.com/products/secureSet/

Fast, clean, and way better than cement in that it doesn’t rot the posts.

A factor not discussed is the view of your county or city building department. In my case the county required 2 foot cubed concrete footings for each vertical post. I could not budge them and finally got a variance to pour a continuous slab pier. It still cost $800 unplanned. The county felt any roofed structure had to meet house footing codes.

Rmiz
You always want to use pressure treated post when putting post in concrete. Ground contact pressure treated post are rated to last a minim of 40 years . As a contractor of 25 years ,I don’t mean to be rude but with the kind of questions your asking I think you should pay someone who has experience to do this job for you.

-- W James Brokenbourgh Custom furniture maker http://artisticwoodstudio.com/

Thanks for the “non-rude” answer haha. Well I’m senior in HS and I consider myself pretty good with wood stuff. I’ve built a pretty nice bar in my basement and other things also. I gotta start somewhere right? If i knew how to do everything I wouldn’t be asking a professional like you, on this forum. Plus, we don’t have the kind of money to pay someone. I ONLY asked where and how to add the posts…..

My friend building a nice bar is a lot different than building a pergola that can fall on folks and injure them. I would follow the suggestion of talking to your local building department and perhaps taking them your drawing of what you intend to do. That would be a lot safer than asking folks on line how to do things because we know how we would build it in our area but your area might have totally different building codes and if you don’t follow the codes in your area the building department can make your tear it down or fine you or both. Good luck on your project.

-- W James Brokenbourgh Custom furniture maker http://artisticwoodstudio.com/

My mate has also the same dilemma, and I directed him to this forum. It helped him construct the same, given their advises and it was great for him to follow some of the advice. In the process he managed to construct these on a very cheap cost. He did rummage into my garden tools storage to find the tools he needed. He did not spend so much. Forums like these are great! Thanks for the tips!

-- http://www.supercheapstorage.com.au