I have attached a shelf that has no visible fixtures on it to a wall in my house. Although it is meant to support up to 15Kg it fell off the wall within 5-6 hours supporting only say 5-7Kg. The shelf is attached by two brackets that are attached to the wall with metal rods extending out from the wall where the shelf is slid onto. The problem I believe is that I live in a post war red brick terrace house and the walls seem very powdery when drilling. Is there anything that I can use, without attaching angle irons or similar, that will ensure the shelf will remain on the wall??? I was thinking rawlbolts? Or is this an overkill? please help as its for the nursery and our child is due any day now! Thank you.