How to get a post plumb using a bolt down anchor?

[mh]

I want to place some posts on existing concrete using Pryda bolt-down post anchors. https://www.bunnings.com.au/pryda-post-anchor-bolt-down-w-washer-100mm-m10_p1070068 The concrete is slightly sloped but the post needs to be plumb. What is the best way to get it plumb? I have done a similar job in the past just using window spacers under the plate, but that was just for a freestanding screen, nothing weight bearing. I want to do it a bit more professionally this time. Thanks. 

Is there a better way to get it plumb?

[SMOKOTIME]

Sorry I'm just a cranky old Engineer who is very tired of support people who have no practical experience.  Their support teem need to set a few posts and see how bad their advice is. 

There is NEVER any guarantee that the foot on a post is square to the upright and any discrepancies will be magnified over the length of the post. 

There is NEVER any guarantee that the pad will be troweled perfectly level or even flat and any discrepancies will be magnified over the length of the post.

He did mention LOAD BEARING and nobody asked what the load is what it is being clad with and what wind exposure it has.

Better to set the post properly and level with a spirit level and then pack to achieve the best compressive strength. 

Otherwise you may as well use tile grout or plastic wedges over an expansion joint. 

[flywind0329]

Sorry , to ask on old post. What is best size of slave for a 90mm post anchor, and which  Dynoabolt Is right product for this application. Thanks! 

[EricL]

Hello @flywind0329, 

Welcome to the Bunnings workshop community. It's wonderful to have you join us.

It's perfectly all right to ask these questions even if it is an old discussion.

Can you please tell us, what is the purpose of your 90mm post? Will it be carrying a heavy load or is it for fencing? Any extra information you can share with us about its purpose will help us give you better advice.  

If you have any other questions we can help with, please let us know.

Eric

[flywind0329]

I think Diy a pergola 3.5m wide x 5m long , long side attached on the house . Maybe 3 x 90mm post with anchor on the concrete slab (driveway ).  

 

[EricL]

Hello @flywind0329 

It’s great to see the photos of your proposed pergola location! This will help in determining the best approach for your build. Since your pergola is quite large at 3.5m x 5m, it’s a good idea to check with your local council regarding any size limits or permit requirements. Larger structures often need approval, so it’s best to confirm before starting construction. Given the scale of the project, engaging a draftsperson or engineer would be a smart move. They can create a proper plan that meets council regulations and ensures structural integrity. With a professionally designed drawing, you’ll have confidence when submitting it for approval, as it will include all necessary details, such as the correct fixings you’ll need for your build.

If you're installing a post anchor into a concrete slab, the slab itself should be at least 100mm thick to provide adequate support. Reinforcing the concrete with mesh is recommended if the post will bear significant weight or be exposed to strong winds. When securing the post anchor to the slab, selecting the right Dynabolt size depends on the specific requirements of your structure, including the base plate of the anchor and the slab thickness. Make sure to drill the correct size hole, clean out the dust, and tighten the bolts firmly without over-torquing to ensure a secure hold.

Here is a link to a handy step-by--step guide: How To Build A Pergola Frame

If you need further assistance, please let us know.

Eric