How do I fill this gap under my balcony?

[RikerZZZ]

Hi all, 
We have an issue with birds nesting in the gap under out balcony above our columns. Due to the rounded shape of the columns we're not exactly sure the best way to tackle the problem. 
Here's a picture of the nest and the size of the gap we're dealing with. 

Ideally we would do something that completely plugs the gap, and remains flush to the outside of the column. Does anyone have a solution they could recommend?

Here are some more pictures:

 

 
Any ideas are appreciated. Thank you. 

[MitchellMc]

Welcome to the Bunnings Workshop community @RikerZZZ. It's wonderful to have you join us, and many thanks for your question about preventing birds from nesting.

You could fill the cavity with wire mesh to block access. Another option is to use a semi-rigid plastic, such as Icon Plastics 150mm x 10m Slate Grey Garden Edge, cut to fit around the column and adhered with Liquid Nails. The grey version looks to be a close match to the column colour. I'd recommend scratching up the plastic edging where you'll be glueing it to the column with 40-grit sandpaper. Some nice deep scratches will help the adhesive stick to it. This would create a neater, more professional finish while effectively sealing off the gap. 

Let me tag @Dave-1 and @Nailbag for their thoughts.

Please let me know if you have any questions.

Mitchell
 

[Dave-1]

Good Afternoon @RikerZZZ 

I was thinking of a more complicated answer until I read @MitchellMc's lol I like his idea tho I might try to install the plastic ring/edge on the inside of the pillar as the shape will help it stay there.

The complicated idea, just to have a second option, was to cut out two of timber so it will form a larger square then the width of your pillar, Then cut out the ark of the pillar with a jigsaw and then plop each half on top and glue them together. I wouldnt use MDF for this as its an outside job tho.

Gravity and the clamping effect would hold it in place. I would leave 5mm gap at the top for expansion just in case tho.

Dave

[RikerZZZ]

Thank you so much for the reply Mitchell, we appreciate the advice. 
I think we'll be going for the garden edging solution. 

Would you recommend any actions to physically connect the edging to the underside of the balcony, or would it be better to just push it up against the top and leave it floating so there is room for expansion?  

[MitchellMc]

Once it's fixed in position, you could run a bead of Sikaflex 11FC around the top, which will secure it to the ceiling @RikerZZZ. However, the edging is fairly rigid, so it should hold position there adequately without the need to adhere it.

Mitchell

[Nailbag]

Apologies for the late reply @RikerZZZ but I can't think of a better more simplistic solution than what @MitchellMc has suggested, which is spot on.

Regards Nailbag