I've cut some scaffold board to fit as shelving in a couple of alcoves. I'd like a floating type support - where you can't see the brackets.
I've managed this with much less substantial wood by cutting a groove in the end of the shelf with a circular saw, then sliding the shelf over some de-headed screws screwed into the wall.
I could try the same arrangement using some bulky screws, but this is slightly complicated by brick walls faced with 40mm of plasterboard and insulation, and the not inconsiderable weight of the shelves and books that'll go on them. Wondering if anyone else has come up with something more elegant . . .