How to anchor metal gate posts above ground into cement?

[Jaden]

Hello,

I am looking to build my first narrow side gate with brick walls either side, just behind the downpipe. The total width of the walkway is 1.12m. 

I would prefer to use steel posts at least 1800mm high, anchored to the cement and brick wall. 

The concrete (32mpa) was poured on September 28th 2024. Concrete depth of 13cm.

The issue I have is that the cement isn't level on the left side with lighter coloured bricks. It needs packing of around 6-10mm. The right side seems to be fairly level.  

Originally I was planning to use protectoral-50-x-50-x-1900mm-black-aluminium-pool-and-garden-flanged-fence-post but now I am unsure how I would level the cement to have proper contact with the post flange. 

Therefore I started looking into the simpson-strong-tie-90-x-90mm bases. Would that type of post base be a better solution and is it suitable for a metal post? Looking to use a Dynabolt 70mm or so into the concrete. Along with anchoring the post to the brick wall with a bracket of some kind. 

I am planning to build the gate similar to the Cypress arch gate 1800mm but instead using a Fortress Gate 1650mm frame.

Thank you for taking the time to read this. I will appreciate any help I can get. 

[TedBear]

Hi @Jaden thanks for adding your interesting project to the Bunnings Workshop. 

I think you are on the right track with using square aluminium posts, but I think that the flanged posts will cause you problems. The flange will prevent, or at least make difficult, attaching the post to the wall to which you will need to bolt it (as well as the flanged base.not fitting in with the slope on the pathway). I suggest that you use a 50mm garden post and fit an end cap to both ends. To help locate the base, you could screw  the lower endcap to the path, ignoring the small slope on one side. Then push the post onto it, then bolt it to the wall as you planned to do. If you use black posts you won't notice the small gap on the bottom. If not using black posts, then just paint the very bottom abt 50mm up, black, and make the top line on the painted strip horizontal. A blind man will be happy to see it, no one else will notice and it won't affect anything because the wall anchoring will be doing the work.

Suggested post:

https://www.bunnings.com.au/protectoral-50-x-50-x-1400mm-black-aluminium-garden-in-ground-fence-post...

Bottom end cap, such as:

https://www.bunnings.com.au/protectoral-50-x-50mm-black-plastic-fence-post-cap_p1141612

[MitchellMc]

Welcome to the Bunnings Workshop community, @Jaden. It's terrific to have you join us, and many thanks for your question about installing posts.

It sounds like you're on the right track with your project! You have a couple of options for levelling the concrete and ensuring your steel posts are securely anchored.

You could either build up the area by creating formwork around the uneven section and then pouring Lanko 20kg 702 Durabed Structural Grout. This will give you a level surface for proper post-installation. Alternatively, if you prefer not to add material, you could cut into the existing concrete with an angle grinder to create a flat pad for the post flange. This method might be more labour-intensive but can be effective in providing a stable, level base.

The Simpson Strong-Tie 90mm bases you're considering are typically used for timber posts, but they could work for your metal posts if you ensure they're properly secured with Dynabolts. Given the depth of your concrete (13cm), a 70mm Dynabolt should provide sufficient anchoring. Just be mindful to check your post's size, as the 90mm base might be oversized for steel posts, so selecting the right fit will be important.

Anchoring the post to the brick wall with a bracket will further stabilise the structure. You'll want to choose a heavy-duty bracket and use appropriate masonry anchors to ensure a solid connection to the brick.

Please let me know if you have any questions.

Mitchell
 

[Jaden]

Thank you kindly for your suggestion. I will definitely consider using post caps at either end of the metal post. 

What cement screw would you recommend to fasten the post cap to the cement? 

[Jaden]

Thank you for your suggestions. 

It would be good to have the metal posts flush to the brickwork, so I will look at getting black steel posts. Might need to look around and find a supplier that makes 90-100mm posts to better fit a Strong Tie base. 

Could you please recommend a good heavy duty wall bracket (50mm or 90-100mm) and masonry anchors that would best suit.

[EricL]

Hello @Jaden 

I propose looking at the Carinya 75 x 50 x 20 x 4mm Galvanised Angle Bracket or the Dunnings 50 x 50 x 50 x 5mm M12 Galvanised Angle Bracket. I suggest using the Ramset 300ml Chemset UltraFix Plus along with the Ramset M10 x 130mm Galvanised Chemset Stud, plus the Ramset Multifit Sieve - 4 Pack. This chemical anchoring set allows you to anchor into solid or hollow bricks. It will be necessary to use a nut and bolt set on the post to hold it in place.

Here is a handy step-by-step guide: Ramset UltraFix PLUS Polyester Anchoring Kit

If you need further assistance, please let us know.

Eric

[Jaden]

Hello,

I have finally installed both metal posts and I thought I would share what I used to get the job done. 

Galvanised steel posts

Australian Handyman 65mm x 65mm Galvanised Steel fence post 

Galvanised steel post cap 

Above ground anchor supports

Pryda 85mm Adjustable Post Anchor 

Macsim 3mm shims  

Ramset 10mm x 75mm Stainless Steel Dynabolt  

VUEPRO M10 90 - 110mm Concealed Thread Bolt Probolt - 2 Pack 

VUEPRO T50 Concealed Bolt Wrench - 2 Pack 

Brick wall brackets

Dunnings 65 x 65 x 65 x 5mm M12 Galvanised Angle Bracket 

ZENITH M12 x 100mm Hot Dip Galvanised Hex Head Bolts and Nuts 

ZENITH M12 Hot Dip Galvanised Flat Round Washers 

Ramset 10 x 60mm Galvanised AnkaScrew Masonry Anchor 

 

• I used smaller sections of 3mm shims just in front of the Dynabolt holes to fix the downward slope of the concrete.
• For the anchor support, I thought it best to line up and drill parallel holes through the 3mm shim and steel post.
• The VUEPRO bolts did a great job of firmly enclosing the steel post and locking it all together.
• The wall brackets had 12mm cut holes, but I found that only the M10 Ankascrew actually fit through the hole. The Zenith M12 nut and bolts fit well.
• I didn't feel the need to use the Ramset Chemset adhesive. The three brackets fixed to the brick and post are solid. I can always use it in the future if necessary. 

It would be good to make the bolt ends shorter, but I am just happy it all came together and looks half decent.

I had decided to attach the middle bracket on the opposite side of each post. Unsure whether that was necessary, but I just thought it would provide added support in the opposite direction as we occasionally get strong Southerly winds that funnel through the walkway.  

Kind regards 

[JacobZ]

Hi @Jaden,

It looks like a very sturdy install that I'm sure will serve you well for years to come.

Thank you for posting the finished project, I'm sure many of our readers will benefit from seeing it complete.
 

Jacob

[Noyade]

Impressive @Jaden! 👍

So, the different walls - your house and garage?

[Jaden]

The lighter brick is my house wall. My neighbour has his brick wall on the boundary line unfortunately, so had no other choice than to mount posts between both brick walls.