Use boxes of the same size, put heavy things like books in small boxes, fill every box to the top so there's no empty space inside, and tape the seams. Then build each stack heaviest at the bottom, on a pallet or boards, with a little air between it and the wall, fragile boxes on top, and, as our house-move guide puts it, "no more than five boxes high unless the bottom boxes are specifically rated for it." A stack collapses from its bottom box, so most of the work happens before the box is taped. Packing stock for a business, boxing up a parent's home, or adding to a unit you already have? There's a section for each below.
For where each stack goes in the unit (back, middle, by the door), see what should go in my storage unit first, and what last?
The box: why a stack collapses from the bottom
| Do this | Why it matters |
|---|---|
| Use one size of box per stack | Our house-move guide says "Uniform box size helps stacking; mixing small, medium and large boxes leads to unstable piles", and "A tall stack of mixed box sizes leans, and a lean becomes a collapse the moment you pull one box out." |
| Put heavy things in small boxes | Our decorating guide says "large boxes filled with light items, small boxes for heavy ones like books." (The smallest our Box Shop sells is the Medium. Its pages give no weight limit, and a Medium full of books is heavy, so if lifting is hard, part-fill with books and top up with lighter things; see how high can I stack for lifting safely.) |
| Fill every box to the top, with no voids | "A half-filled box compresses under weight; the box above it sinks, the stack becomes unstable, and things break" (house-move guide) |
| Tape the seams | "Seal boxes properly; tape the seams, not just the top flap" (house-move guide). For heavy boxes, our packing tips add: "Reinforce the bottom with tape for heavier items" |
Same-size boxes and small boxes for heavy things fit together if you build each column from one size: a column of small book boxes, a column of large boxes of bedding. Never stand a small box under a bigger one. Its product page calls the Medium (457 x 330 x 330mm) "ideal for books, kitchenware, electronics, and small household items". What boxes does the Wigwam Box Shop sell? covers every size.
Full should still close flat: fill the gaps with paper or soft things until nothing moves, because a domed lid won't take a box on top evenly.
Building the stack
Start with a base. Put a pallet or boards down first. Our market traders guide says: "Keep boxes off the floor on a pallet or shelving rather than directly on the slab." Our Box Shop doesn't sell pallets; ask us when you book whether your site has any.
Heaviest at the bottom, fragile on top. Our house-move guide: "Stack heavier boxes on the bottom, lighter boxes on top", and "Fragile items go on top of stable stacks and near the front where you can reach them without climbing." Never put a heavy box on a fragile one, whatever the sizes. A heavy, fragile box, like plates, goes low in a short stack of its own. Our heirlooms guide says "Pack plates and bowls upright rather than flat; they bear weight better that way."
Five high, as a guide. Five boxes high is our guidance; our storage terms don't set a stacking limit for general goods (battery goods are the exception, below). Five high is about 1.65m in our Medium boxes (330mm tall) and about 2.5m in our Large boxes (500mm tall), so a Large stack ends above head height (five Extra Large would be about 3.75m). Our house-move guide also says "never build a stack you cannot dismantle without standing on something unstable". Our Box Shop pages don't publish a load rating for the boxes, so if you're unsure whether yours can take more, ask us. Unit heights aren't published: see how high are the units?
In a small unit, or with only a few boxes. Our smallest-unit guide says "Build upward in even tiers so nothing leans." Ten Medium boxes make two columns of five, each about 1.65m high.
A little air at the walls, neat rows between stacks. Our garden furniture guide says "Leave a little air around items rather than compressing everything tight against the walls." Between stacks, our house-move guide says "Gaps between stacks catch belongings and waste space; aim for neat rows."
Free-standing only. Our terms say you mustn't "paint or make alterations to or attach anything to the internal or external surfaces of the Unit" (clause 22(d)), so no brackets, screws or straps into the walls. The terms don't mention freestanding shelving or racking; our market traders guide says "Bring your own shelving if it helps", so keep any shelving free-standing, and ask us about anything large or heavy.
Battery items stay out of the stack. Anything with a built-in battery (laptops, tablets, battery toys) must be stored so that "such Goods are not stacked and are stored allowing air circulation" (clause 20.1(b)). Clause 20(d) also says you must not store "more than ten (10) laptops, tablet computers, children’s toys or other similar items containing built-in batteries." Keep them out of the box towers, near the front where you can see them.
Is it safe to stack boxes high?
It can be, if the bottom boxes are full, taped and the same size as the ones above, and the stack sits on a flat base. The terms also put the risk to your goods on you: "The Goods are stored at Your sole risk and responsibility and You shall be responsible for and bear the risk of any and all theft, damage to, and deterioration of the Goods caused by any reason" (clause 30). Your goods must also be insured while they're stored (clause 31), through our contents protection or your own policy. Stack only as high as you can lift the top box down safely. Anything leaning on the inside of the door can fall towards you when you open it, so stop the load a step short of the doorway.
Stacking business stock
Supplier cartons in one size stack the same way if they're full and sound: same size per column, heaviest at the bottom, off the slab on a pallet or shelving. A thin or part-filled carton is a weak bottom box, so repack it or put it on top. Our market traders guide describes the usual layout: "heavy items on the floor, lighter packaging on shelves at mid-height, and fast-moving lines closest to the door."
If you pick orders every week, keep the lines you pick from at the front, or on shelving at mid-height, not buried in a five-high column. Our pick-pack guide says "You can pack and organise stock there", while clause 22 says you "will use the Unit solely for the purpose of storage", so the unit can't be a shopfront, and our guide to selling from a unit explains the limits.
Whether our contents protection suits business stock, and how the Replacement Value in clause 31 applies to it, is something to ask us about when you book, or check with your own business insurer. If your stock arrives on pallets, see can I store goods on pallets? for deliveries and handling.
Packing for a parent or relative
You may not be the person who unstacks it. Keep heavy things like books and china in small boxes so they're easier to lift, fill every box so it can take weight, and label the side of each box with what's inside and who it's for (see our labelling guide).
Adding to a unit you already have
Check the bottom row before you add boxes. A bowed or sagging box is carrying more than it can, often because it wasn't filled to the top. Repack it and rebuild that stack first.
Getting the boxes
If you're packing now, our Box Shop sells double-walled boxes in the sizes above, plus tape and packing paper. If you haven't got a unit yet, get a price online or call us on 0800 2545585.
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