cobweb

So I want to tile this wall which will be part of a wetroom. The sequence I've got here is, I think: -cob -lime render -cement render cement render with pebbles -external paint -cement render -plaster It's a little hollow, a couple of small cracks, but I think is stable enough not to justify...

I have seen this product that is designed to keep spiders of of CCTV camera, and just wondering if anyone has used it before and is it any good? Just need a way of keeping spiders of my CCTV cam's outside as the cobwebs blowing in the wind keeps triggering the motion detection at night...