Storage and shelving dimensions

Storage is usually designed backwards. The wall offers a width, somebody fills it, and the depth, span and height are whatever the joiner had in stock. In the right order every one of those numbers is set by something physical: a hanger, a book, an arm, a stiffness value. The order is depth, then span, then pitch, then height, then the space in front, and each decision closes off the ones after it.

Depth is set by the largest object, and it cannot be fixed later#

Depth is the only storage dimension with no cheap remedy. A closet interior is 24 in (61 cm) deep because the rod sits 12 in (30 cm) off the back wall, a standard hanger is 17 to 18 in (43 to 46 cm) across, and a winter coat bulks the rest. Take 2 in (5 cm) out of that and the door will not shut on a jacket.

Everything else in the house has an equivalent governing object.

The lesson repeats in every row of that table: storage depth is a single-item dimension plus a tolerance, never a round number chosen for looks. The full by-content set is in shelf depth and vertical spacing by content, and the two awkward cases, deep pantry runs and record collections, are worked through in pantry dimensions and book, vinyl and media storage dimensions.

Then the span, because depth does nothing for sag#

A shelf is a simply supported beam, and its deflection scales with the fourth power of span and the cube of thickness. Depth barely appears in it, which is why a deep melamine shelf sags as badly as a shallow one. For books at about 20 lb per foot (30 kg per metre), hold 3/4 in (18 mm) melamine to 28 to 30 in (71 to 76 cm), plywood to 36 in (91 cm) and solid hardwood to 48 in (122 cm). Records halve all three. The arithmetic, including the creep that bows an acceptable shelf over a few years, is in shelf span, thickness and sag, and the shelf span calculator runs it for any combination.

The consequence is a rule about bays, not boards: divide the wall into a whole number of bays your material can hold, then build. The carcass sizes that follow are in built-in cabinetry dimensions, and in millimetres the modules land differently again, as millimetre cabinet and joinery sizes sets out.

Then the pitch, which is where capacity is won and lost#

Vertical spacing is the cheapest capacity in a house and the most commonly wasted. Shelves at 12 in (30 cm) centres with a 3/4 in board give 11.25 in (29 cm) of clear opening, which suits general books. At 16 in centres the same 8 ft (2.4 m) of height gives six shelves instead of eight, a quarter lost to air.

Adjustable pins cost almost nothing at build time and are the only way to keep the pitch honest as contents change, though fixed shelves buy about 20 per cent less sag. The shelf-by-shelf figures for a household's most awkward stack are in linen closet dimensions and shelf spacing.

Then the height band, and everything that falls outside it#

The comfortable band runs 30 to 60 in (76 to 152 cm) above the floor. Below 30 in you crouch, above 60 in you stretch, and above about 72 in (183 cm) you need a step. That comes from shoulder height and arm length, derived in reach zones and useful storage heights; accessible design tightens it to a 15 to 48 in (38 to 122 cm) range.

Hanging is the special case, because a rod is a height decision and a capacity decision at once. A single rod at 66 to 72 in (168 to 183 cm) takes anything; two rods at roughly 42 and 84 in (107 and 213 cm) double the hanging length in the same width and cap every garment at about 40 in (102 cm) of drop. Lengths, loads and rod diameters are in hanging rod heights, lengths and capacity, and how the two systems divide a carcass is in wardrobe internal dimensions and divisions. Sloping ceilings turn the band into a graph rather than a number, which is why under-stair storage dimensions is its own problem.

Last, the space in front, which is not yours to spend#

Storage is only as good as the floor in front of it, and that floor usually belongs to circulation too. Thirty inches (76 cm) lets one person stand and reach; 36 in (91 cm) makes the same strip a route, matching the widths in walkway and circulation widths at home; 42 to 48 in (107 to 122 cm) is what a walk-in with hanging on both sides needs, since garments project 24 in from each wall before the aisle begins. Walk-in closet dimensions and layouts shows where that aisle earns its keep, usually only above about 6 x 7 ft (1.8 x 2.1 m), and reach-in closet dimensions covers the case where the aisle is the bedroom and therefore free.

Capacity is linear, and it is worth counting before you build#

Storage is sold by volume and used by the linear foot. Hanging runs about 1 in (25 mm) per shirt, 1.5 to 2 in (38 to 51 mm) per jacket and 2.5 to 3 in (64 to 76 mm) per winter coat, so a 60 in (152 cm) rod holds roughly 40 shirts or 20 coats, not both. Shelving runs 8 to 10 hardbacks per foot, or 55 to 65 LPs.

Counting the contents first turns storage from a guess into a specification: so many inches of rod, so many linear feet of shelf, so many drawer boxes. The depth, span, pitch and height decisions then package that number in the order given, and the wall width becomes the last thing you look at rather than the first.

In this section#

• Shelf span, thickness and sagKeep a loaded shelf under a 1/180 deflection limit: 30 in (76 cm) for 3/4 in melamine, 36 in (91 cm) for plywood, 48 in (122 cm) for solid oak.