What you will need:

The shelves are all meranti, 144x12x385mm, the base
is SA pine, 144x12x560mm, and the five front pieces are 144x22x35mm (bottom
piece), three centre pieces each 22x144x130mm and a fifth, top piece, which
is 22x144x90mm. You, however, can adapt these dimensions as you see fit.
The only point we would make is this: don’t make the shelves too deep as
they are held only by the portion that is in the gap between the front
pieces mounted on the base – and those front pieces should be at least 22mm
thick, as here.

Method:

  1. Cut four or however many shelves you plan for your unit.
  2. Floating Shelves Image 1

  3. We selected four, cut from 12x144mm meranti.
  4. Floating Shelves Image 2

  5. Position them on a length that will become your base, and only then
    decide on a length for the latter, then cut it to length.
  6. Floating Shelves Image 3

  7. Initially we were looking at the bottom piece being 20mm wide, but
    decided that that would be too narrow and weak. So, we changed it to
    35mm.
  8. Floating Shelves Image 4

  9. We used some scrap block board for the front pieces, and…
  10. Floating Shelves Image 5

  11. Cut the five pieces – all 22x144mm wide, but 35mm, 90mm, and then
    three pieces 130mm deep.
  12. Floating Shelves Image 6

  13. Using some offcuts from the shelves, to confirm everything matched
    up.
  14. Floating Shelves Image 7

  15. The components – 10 in all.
  16. Floating Shelves Image 8

  17. Smarten up the edges a little with a concave router contour.
  18. Floating Shelves Image 9

  19. The easies way to rout the edges is by clamping the front pieces
    together and then routing along the edges in one go.
  20. Floating Shelves Image 10

  21. Here’s the result – clamping them together actually makes them
    easier to handle. Of course, you could also rout the single length
    you’ve selected for the front pieces, and then cut each to length. I’ve
    only just thought of that, so try it.
  22. Floating Shelves Image 11

  23. Routing across the ends risks chipping, and the answer is to clamp
    both ends together, between two pieces of scrap of the same thickness –
    in this case, 22mm.
  24. Floating Shelves Image 12

  25. Then rout them
  26. Floating Shelves Image 13

  27. And this is the result – no chipping.
  28. Floating Shelves Image 14

  29. You can clean up the ends, and any other concave routed contour,
    with a suitable dowel and sandpaper.
  30. Floating Shelves Image 15

  31. Sand down the surfaces.
  32. Floating Shelves Image 16

  33. Apply glue to the back of the bottom piece and…
  34. Floating Shelves Image 17

  35. Clamp it firmly in position.
  36. Floating Shelves Image 18

  37. Insert a couple of spacers from the offcuts of the shelves, and
    glue the next front piece into position.
  38. Floating Shelves Image 19

  39. Carry on until you have attached each front piece in position; note
    the spacers between each, so that the shelves will fit very snugly.
    Allow the glue to dry; if you wish, you can drive small screws through
    the back of the base to secure the front pieces even more strongly.
  40. Floating Shelves Image 20

  41. The attachment screws go through the base – and won’t be visible.
  42. Floating Shelves Image 21

  43. In this case, I didn’t have a countersink bit small enough (no! I
    don’t have everything!). Therefore, I used a 10mm HSS bit to
    countersink each hole; the screw heads must not protrude at all
    otherwise you will not be able to seat the shelves properly.
  44. Floating Shelves Image 22

  45. Having tapped the spacers out, and clamped the front pieces for
    good measure while the glue cured.
  46. Floating Shelves Image 23

  47. Finally, position the base on the wall, drill the required holes in
    the wall, insert plugs, and attach the base to the wall. Then slide the
    shelves into position… And you’re done.
  48. Floating Shelves Image 24

  49. The final effect – one position.
  50. Floating Shelves Completed

  51. The final effect – another position
  52. Floating Shelves Completed