Holes in polycarbonate covering

[MrE]

Hi
We've got two things with polycarbonate sheeting, a curved porch covering, and a lid of a cold frame. Pictures included. They are about 2-3 years old, and they have small holes all over them. I have no idea how they appeared or when. My only guesses are hail stones or some sort of insect making the holes.
I have never seen anything like this before.
Does anyone know how these have happened.
View media item 104377View media item 104376View media item 104375

 

[footprints]

Neighbour with a BB or pellet gun? Some idiot firing a shot gun into the air nearby?
Any small stones or missiles found underneath?

 

[MrE]

I think a pellet gun would do more damage, and i know of no-one around here with one (i know all my neighbours). No shot gun either.
No small stones or any debris. the holes are really neat. And the two different polycarbonates are about 40ft apart.

Anyone else ever seen this?

 

[catlad]

I'm with hail stone.

 

[Alastairreid]

Acidic bird poop.

 

[MrE]

im pretty sure its not bird poop based on i dont see any poop anywhere. But good idea.

 

[Mw Roofline]

Those funky canopies were big some years back due to their aluminium curved design and ease of fit as well as good value for money. However they all came with shockingly shyte 5mm greenhouse poly. It’s the same poly that’s used to replace greenhouse glass.

It’s all they could use that would flex around the curve. 10mm or above wouldn’t bend because of the flutes.

The act of bending the poly along that short curve in effect stretches the outside layer and makes it susceptible to attack from falling things and it’s easily damaged.

so the answer to your question is I don’t know what exactly has caused the holes but it’s easily damaged cause it’s thin and wasn’t really meant for this application in the first place and there will be thousands others out there like yours.

 

[MrE]

Thanks for the detailed feedback Mw. The other item in the garden with (what looks like) the same material in the lid is a 'mini greenhouse'. It's not curved and got exactly the same sized holes. That was bought new in 2018. Surely 5mm poly lasts more than 2 years?

 

[Mw Roofline]

Positioned upright like glass is better than being used as a roof where it gets battered.