Drilling into a concrete fence panel

DubLad69

Hi all,

Our back garden is surrounded by these ugly concrete fence panels. I am planning to attach a trellis over each one and grow plants up them.

My question is, are these panels likely to crumble or break apart if I drill into them? Has anyone here done something similar before? I can’t get a trellis wide enough to attach to the actual posts, so it would need to be attached to the panels.

Lumen

The obvious problem is that regardless of how you attach, you're going to be adding load to one side of the fence, and that risks pulling it over eventually.

That aside, if I was doing it I'd use an appropriate construction adhesive (probably MS polymer-based, like one of the tec 7 products*) to sister treated timber posts to the existing concrete posts, and again to the mid-point of the panels, and then screw the trellis into those (obvs using different thicknesses to bring it all out to the same level). I would seat the mid-point posts on plinths (e.g. concrete blocks sunk next to the fence) so that the panels aren't taking any more vertical load, they're just add lateral stabilility.

No way would I drill into the concrete posts or panels. Chemistry is underrated.

(*) FWIW I really hate the tec 7 data sheets, they claim it supports "27kg of load" but that's completely meaningless without specifying the contact area.

The Continental Op

Another shout out for "No way would I drill into the concrete posts or panels". I've seen the way they deteriorate over time and once water can get into them the reinforcing rods inside start to rust then they become a right mess. Almost impossible to drill without hitting and exposing the steel reinforcing.

Just forget whats there and put your trellis on its own supports. If you want to tie the two together with your neighbours agreement you could lift the top panel up and put a wooden strip cut to fit between the top panel and the one below it then you have something you can fix into.

DubLad69

Thank you. So essentially I would put concrete blocks into the ground, place new fence posts on top of them to hold the downward pressure of the trellis and plants. Then I would use construction adhesive to glue wooden posts to the fence/posts as it currently is?

Would this work for creating something like this screening too? Or would it be necessary to dig a deeper hole and pour concrete around the posts? (Which i would rather not do)

youtheman

Why don't you just connect a suitable bracket and then drill into that?

Tree

I've tec-7'd trellis for peas up onto those panels (or was it no more nails?). Been up for four years now, peas still happy to grow up it. Put a dab along most of the edges.

Lumen

https://www.boards.ie/discussion/comment/120350423#Comment_120350423

I was only suggesting using ground-supported fence posts in the mid-section of the panels, for the posts I would just glue thick battens directly to them i.e. sistered (obvs using different thicknesses of timber to bring out the mid-section posts to the same level as the sistered ones). I wouldn't use full fence posts either, just thick enough to take a screw (e.g. 1.5" or more) when the trellis is attached.

The principle here is to avoid applying a load to something in a way that it wasn't designed to take. The panels are presumably not designed to take additional load, and concrete is really bad in tension - you can think of each panel as a beam to which you are applying a load it wasn't designed to take.

But I think @Tree has suggested that they glued the trellis directly to the panels and it was fine. 😀

It's just a question of how much load they're going to take. For instance, what if a child climbs up the trellis, or an adult does so whilst trimming something or whatever? I would err on the side of caution, but I do tend to overthink/overengineer things.

Tree

It's a twenty quid trellis from Woodies, it only needs to deal with peal :) It's the weakest part of the whole thing (and we've no kids or pets to climb on it). Though the neighbours kids kicking football at the panel from the other side is probably more of a worry, they're getting big now.

DubLad69

Thanks guys. I've decided to build a whole new wooden fence/screen in front of our existing concrete fence, just taller.

I’m going to to basically what was advised here. Glue the new fence posts to the existing ones with the strongest construction adhesive I can find. But also concrete this post and another post halfway between the current posts into the ground.

Its probably a little bit of overkill, but better to be safe than sorry.