Most people underestimate how much they can fit in a storage unit — and most people also make it harder to retrieve things than it needs to be. A bit of planning before you start loading makes a real difference to both.
This guide walks you through everything: how to choose the right size, how to pack your boxes, how to arrange everything in the unit, and how to make sure you can actually find things again when you need them.
Start with the right size unit
The best packing job in the world won’t save you if the unit’s too small. Equally, you don’t want to be paying for space you don’t need.
As a quick guide: a 25 sq ft unit fits a studio flat’s worth of boxes and a few smaller pieces of furniture. A 50 sq ft unit takes the load of a transit van — perfect for a one-bedroom flat. A 100 sq ft unit is roughly the size of a single garage and fits a two to three-bedroom home.
Use our storage size calculator if you’re not sure — it’ll give you an instant estimate based on what you’re storing.
Pro Tip:
If you’re between two sizes, go for the larger one. The cost difference is usually small, and the extra space makes loading, stacking, and retrieving things significantly easier. A cramped unit is false economy.
Before you start packing: a five-minute plan that saves hours
The biggest mistake people make is loading a storage unit in the order things arrive. The result: the things you need most end up at the back, buried under everything else.
Before anything goes into the unit, take five minutes to sort your items into three groups:
- Rarely needed — seasonal decorations, archived documents, items in long-term storage. These go in first, at the back and sides.
- Occasionally needed — things you might want to access every few months. These go in the middle.
- Regularly needed — anything you’ll want to get to while the unit’s active. These go in last, nearest the door.
Leave a clear access path down the middle of the unit if you’re storing for more than a month or two. It takes up a bit of floor space, but saves a lot of shuffling when you need something.
How to pack your boxes properly
Poorly packed boxes cost you space and risk damaging your belongings. Here’s how to do it right.
Use uniform box sizes where you can
Uniform boxes stack cleanly and waste less space. Mixed shapes — odd wine boxes, carrier bags, bulging bin bags — can’t be stacked efficiently and leave dead space between layers. Invest in a supply of the same-sized boxes. It makes a noticeable difference to how much you can fit in.
Pack boxes to their full height
A half-full box will collapse when something’s stacked on top of it. Fill boxes to their full height — use clothes, towels, or packing paper to top them off. A full, firm box stacks well and protects what’s inside.
Heavier items at the bottom, lighter at the top
Books, kitchenware, and tools go at the bottom of each box. Lighter items — bedding, clothing, cushions — go on top. This applies both inside individual boxes and to how you stack the boxes themselves in the unit.
Protect fragile items properly
Wrap fragile items individually in packing paper or bubble wrap before boxing them. Mark the box clearly on all four sides — not just the top. When a box is part of a stack, you can only see the side, not the lid.
If you’re storing valuables, antiques, or anything particularly delicate, see our full guide: How to Store Fragile Items in Self Storage
How to arrange everything in the unit
The order things go in matters as much as how they’re packed. Follow these steps and you’ll get more in — and be able to find things easily.
- Clear the floor of anything that can go vertical
Wardrobes, bookshelves, and drawer units can stand on their ends or sides if they’re not too delicate. This frees up floor space for boxes, which are far easier to stack and arrange. - Build walls of boxes along the back and sides
Stack boxes from floor to ceiling along the back wall and both side walls first. Use the heaviest, least-needed boxes at the bottom. Keep the stack stable — never lean — and aim for vertical columns rather than a pyramid shape. - Slide furniture into the remaining space
Large furniture pieces — sofas, mattresses, tables — fill in the middle and towards the front. Sofas and mattresses can stand on their ends to save floor space. Wrap them in dust covers or moving blankets to protect the fabric. - Disassemble what you can
Bed frames, dining tables, flat-pack furniture, and wardrobe rails all take up a fraction of the space when disassembled. Keep fixings in a labelled zip-lock bag taped to the relevant piece — there’s nothing worse than reassembling a bed frame with a bag of mystery screws. - Use the insides of things
Wardrobes, chest freezers, washing machine drums, suitcases — all of these have usable space inside them. Fill them with soft items: clothing, bedding, cushions. This is one of the simplest ways to fit significantly more into a unit. - Leave your access path last
Once everything else is in, make sure there’s a clear route to anything you’ll need to access during the rental. You’re far more likely to actually keep the unit organised if getting to things doesn’t require moving half the contents.
How to protect your belongings while they’re in storage
Attic’s facilities are clean, dry, and well-maintained — but good packing practice still makes a difference, especially for longer-term storage.
- Wooden furniture: Give it a light polish before storing. Lift it off the floor on pallets or boards if you’re storing for more than six months — it keeps airflow underneath and prevents moisture from sitting on the base.
- Sofas and mattresses: Use breathable fabric covers rather than plastic wrapping. Plastic traps moisture and can lead to mildew. Breathable covers protect from dust while letting the material breathe.
- Electronics: Store in their original packaging where possible. If not, wrap in anti-static bubble wrap. Don’t stack heavy items on top of them.
- Mirrors and artwork: Store vertically, never flat. Flat storage puts uneven pressure on frames and glass. Use mirror boxes if you have them, or wrap in moving blankets and mark clearly.
- Clothing and soft furnishings: Use vacuum storage bags if you want to maximise space. Avoid cardboard boxes for long-term fabric storage — they can introduce moisture. Plastic crates with lids are better.
- Documents and paperwork: Use airtight, waterproof file boxes. Label the outside with the date range and contents so you don’t have to open every box to find what you need.
Storing a lot of furniture? We go into more detail on sofas, beds, wardrobes, and wooden pieces in our dedicated guide: What’s the Best Way to Store Furniture?
Label everything — properly this time
Labelling sounds obvious. Most people still don’t do it well enough.
Write on at least two sides of every box — ideally three. When a box is stacked in a unit, you can see the front and one side. If the label’s only on top, it’s invisible. Write the room it came from, a rough list of contents, and whether it’s fragile.
One step further
Keep a simple inventory — even a photo on your phone of each box’s contents before you seal it. When you’re looking for a specific thing three months later, you’ll be glad you did. A shared note in your phone or a quick spreadsheet works perfectly.
Number your boxes and keep a master list. ‘Box 12 — Kitchen: small appliances, cookbooks, mugs’ takes thirty seconds to write and saves you opening eight boxes looking for the coffee machine.
Quick reference: the essentials at a glance
Before you load
- Sort into rarely needed, occasionally needed, and regularly needed — load in that order
- Disassemble furniture wherever possible
- Invest in uniform-sized boxes
Packing boxes
- Fill every box to full height — top up with soft items
- Heavy items at the bottom, light items on top
- Wrap fragile items individually and label on all four sides
Loading the unit
- Build box walls along the back and sides first
- Use the insides of wardrobes, suitcases, and appliances
- Store sofas and mattresses vertically in breathable covers
- Leave a clear access path to anything you’ll need during the rental
Labelling
- Label on at least two sides of every box
- Keep a numbered inventory with photo or written contents list
Your packing questions, answered
How do I make the most of a small storage unit?
Stack to the full height of the unit — most people underuse the top third of their space. Use uniform boxes that stack cleanly, fill every box fully so they don’t collapse, disassemble furniture to reduce footprint, and fill the insides of wardrobes and suitcases with soft items. A well-organised small unit can fit considerably more than a haphazardly loaded larger one.
Should I use plastic boxes or cardboard boxes for storage?
For shorter-term storage, quality cardboard boxes are fine and easier to work with. For longer-term storage — anything over six months — plastic crates with lids are better. They’re more moisture-resistant, stack more cleanly, and protect soft items like clothing and bedding more reliably. Avoid thin plastic bags and bin liners for anything you actually care about.
How do I stop my belongings getting dusty in storage?
Use dust covers for furniture, especially sofas, mattresses, and wooden pieces. Keep boxes sealed. At Attic, our units are clean, dry, and well-maintained — but a dust cover costs very little and gives you an extra layer of protection, especially for longer-term storage.
Can I stack boxes on top of furniture in a storage unit?
Yes — flat-topped furniture like wardrobes, chests of drawers, and dining tables make excellent platforms for lighter boxes. Make sure the furniture is stable and the boxes aren’t too heavy. Don’t stack anything directly on sofas or mattresses, as this can leave permanent marks.
How should I store a sofa in a storage unit?
If space allows, stand it on its end — this dramatically reduces its floor footprint. Wrap it in a breathable fabric cover (not plastic, which traps moisture). If you can’t stand it vertically, place it cushion-side down or protect the fabric with moving blankets before stacking lighter items on top.
Do I need to do anything special to store a mattress?
Store your mattress vertically if possible — flat storage puts uneven pressure on the springs and filling over time. Use a breathable mattress cover, not plastic wrapping. If you’re storing for a long period, lay it flat only if absolutely necessary, and avoid putting anything heavy on top of it.
Ready to move in?
If you’ve got everything sorted and you’re ready to book a unit, you can get an instant quote online — no deposit, flexible contracts, and 24-hour access as standard across all our London stores. Up to 6 weeks free for new customers. Not sure which size is right for you? Try our storage calculator or give your nearest store a call — our team are happy to help you figure it out before you book.
Posted on 25th March 2026 by Shanaiqua Desa
