How do I level fence posts anchored on to un-level concrete?

[tombullen]

Hello, I'm hoping someone can give me some advice.

I'm installing an aluminium screening fence on to aggregate concrete and surprise surprise, I'm having real trouble getting my posts properly vertical. I have bolt down post brackets (link below) that the posts slide over the top of which means the anchor itself needs to be perfectly level because there's no play available for the posts. 

https://www.aluminiumscreening.com.au/our-products/Black-Post-bracket?limit=100

I've used anchors to bolt the posts to the concrete (link below) and the posts are not level in two directions - both forward and back, and side to side. What I've tried to do is use some stainless steel or galvanised washers that I had lying around to lift up the bracket on one side and that gets me close to vertical in one direction (side to side) but not back to front. 

https://www.bunnings.com.au/ramset-8-x-40mm-stainless-steel-dynabolt-plus-hex-nut-masonry-anchor_p22...

I've done some googling and looked through this forum and these are the options I have so far:

1. Buy some more washers and keep trying to fine tune the levelling, and put the washers on all four anchors if need be. I could fill any gap with a sealant of some kind so it looks neat once complete.

2. Build a pad with structural grout and hope that, as it's liquid, it will self-level. The risk here is that it may end up being too high and then once it's set I don't have enough screw for the bolt to bite into, and then trying to fix that problem would be a real headache.

3. Use mortar or concrete and using a small but thick mixture I could dollop some under the post bracket and then squish it down as I level out the post. Because it's non expansive it would act like a coaster, and I could keep squashing it down enough until I can definitely get the anchor bolts to grip the screw. 

4. Go scorched earth and pull out the existing anchors, re-hire a concrete drill, and either drill in larger anchors and try option 2 with a 1cm footing, or find a new bracket that allows me to adjust the post when attached. Not sure if there are any brackets though as the post is 76mm by 76mm so an odd size.

Any advice would be appreciated! I thought this would be a simple job but it's become a small nightmare!

Thanks,

Tom

[Dave-1]

Afternoon @tombullen 

Welcome to the Community, its a pretty good place to wander through and get some ideas. Your idea tho is spot on already. 

When I have had to level a light post for the same reasoning (and yeah it was me pouring the concrete I used a few metal washers and switched them around until it was true vertical. I have used washes on all four pins on a post before. It happens "shrug" But you are doing the right thing.

I have also used these Macsim Fasteners 75mm Assorted Window Packers - 90 Pack to help pack out edges so it would be a vertical surface.

You could do a combo of the washers or packers then once the post is installed mortar around the base?

Dave

[EricL]

Hi @tombullen 

Allow me to welcome you as well to the Bunnings Workshop community. It's sensational to have you join us, and thanks for sharing your question about levelling your fence posts.

It's great that you've received excellent advice from @Dave-1. I totally agree with the suggestion of using washers to level the post, it's the most convenient way to level it without having to put new concrete in or pull out the bolts. If you wish to keep it looking neat and tidy you can fill the space with construction grout or mortar. 

If you need further assistance, please let us know.

Eric

[tombullen]

Thanks @EricL and thanks @Dave-1.  I'll swing past Bunnings and pick up some washers and get these posts level!

I guess the simplest answer is usually the best!

[Noyade]

All of the above @tombullen 

Plus - would it be helpful to angle-grind areas with a masonry disc - ultimately to reduce the number of washes needed?

Trial and error.

Looking at the schematics you posted - the base is only around 100mm X 65mm.

Cheers.

[tombullen]

For anyone else that has this issue in the future - the order in which you tighten the anchor bolts also affects the angle the pole ends up in. So play around with the bolts and you might get a better result.

For me, in the end, I ended up removing the gate and fence and moving it back 20cms and concreting longer posts in to the ground. The anchor for the gate post was just not sturdy enough to handle how heavy the gate was - it was 40mm aluminium batten, 1.8m high. 

For the bin screen, I got one of the posts in pretty solid but the other I've had to use brackets to attach it to a concrete retaining wall that it sits against, because those anchors weren't sturdy enough either. 

If I could do it again I would have just put the posts in the ground to start with and saved myself a huge amount of pain!

[Dave-1]

Thank you @tombullen 

I am glad you have solved the problem but man it sounds like an effort. Your questions will help others for sure. With that in mind is their any chance of a photo or two of how you had the problem and your solution? Plenty of times I have started down a track only to realise it wasnt working and then changed what I was doing. Its always an upward learning curve.

Dave