I got some IKEA Algot shelves tall uprights. The PDF manual can be found here.

The installation instructions say:

Hang the wall uprights from the mounting rail, correctly space them and then secure them to the wall. Use roundheaded screws with a 4–4.5 mm diameter (screw head max. 9 mm). You will need:

  • 3 screws for the 56 cm (22″)
  • 4 screws for the 84 cm (33⅛″)
  • 8 screws for the 196 cm (77⅛″) high wall upright.

And these are the weight ratings per shelf:

40 cm (15¾″) width

  • 38 cm (15”) depth 15 kg (33 lbs)
  • 58 cm (22⅞") depth 23 kg (50 lbs)

60 cm (23⅝") width

  • 38 cm (15") depth 22 kg (49 lbs)
  • 58 cm (22⅞") depth 34 kg (75 lbs)

80 cm (31½") width

  • 38 cm (15") depth 30 kg (66 lbs)
  • 58 cm (22⅞") depth 46 kg (101 lbs)

I live in a block built with beams so inner walls are not structural. All internal walls are 10cm AAC (autoclaved aerated concrete aka aircrete or thermalite). How does one estimate the load capacity of a shelf and also multiple shelves put on 2 uprights or 2 sets of shelves put on 3 uprights? Is there a way to calculate an estimated weight support.

I'll use AAC Wall Plugs (1st) or universal Fischer Duopower (2nd).

AAC wall plug universal Fischer Duopower wall plug

So we have:

  • 10cm AAC 2.5m tall wall
  • wall plugs 4mm diam, 30-50mm deep (I assume this affects load capacity)
  • uprights with 8 screws (196cm)
  • 2 uprights with a 6 shelf max (16 plugs)
  • 3 uprights with a 12 shelf max (24 plugs)
  • 60cm spacing between uprights (shelf size)
  • shelf weight capacity is available above

Is there any way to factor this in and get some load capacity estimates? I want to put some books on some shelves and they're not eBooks. :)

  • 1
    Welcome to Home Improvement. Very well done for a first question! Please take the tour and read through the help center so you can get the most out of the site.
    – FreeMan
    May 28, 2020 at 13:57

1 Answer 1


Here you go - Multiply the number of brackets by the safe load of the bracket to determine the safe load capacity for the entire shelf. For a shelf that has three brackets rated for 250 lbs. the safe load for the brackets is 62.5 lbs., and the capacity for the shelf, as a whole, would be 187.5 lbs. I was going to do the math but math.

  • But my main concern is the wall material: AAC. How does it count in the calculations?! Since the bracket in theory can take a LOT of weight but if the wall is too thin, doesn't it become a problem. AAC is not full-on concrete.
    – theKI
    Jul 29, 2020 at 0:40
  • It is stronger than brick. It will not be an issue. "The compressive strength is relative factor which defines the load carrying capacity of the material. The Compressive strength of AAC block is 3 to 4.5 N/mm2 while of clay brick is 2.5 to 3.5 N/mm2. AAC blocks for load bearing structure can be used." Jul 30, 2020 at 2:44

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