Start With the Loft Itself — Is It Dry Enough?

Loft spaces are brilliant for storage, but they are not neutral environments. Under a tiled or slate roof, temperatures can swing from a few degrees below freezing in a January cold snap to well over 40°C in a summer heatwave. That constant cycling drives moisture in and out of fabrics and, over months, can leave wool smelling musty and cotton spotted with mildew. Before you carry a single crate upstairs, spend a few pounds on a small hygrometer and leave it in the loft for a week. Aim for a relative humidity below 60 per cent; if it sits above 65 per cent for most of the year, textiles stored there will struggle.

While you are up there, check for the obvious signs of trouble: damp patches on the roof underlay, daylight showing through, droppings or gnawed cardboard. Fix leaks and block obvious gaps before you store anything. If your loft has thick mineral wool insulation, wear gloves and a dust mask when moving around, and never compress the insulation with crates — it needs to stay fluffy to do its job.

Prepare Every Item Before It Goes Up

Most storage damage happens before things are packed. Moths are drawn to the traces of skin oils, food and perspiration left on clothing, so wash or dry-clean everything before it goes away, even a jumper worn only once. Check that items are bone dry — a hint of dampness in a folded jumper will spread through the whole crate. Give woollens and knitwear a close look at the seams, cuffs and underarms for small holes or fine webbing, and deal with any infestation before it joins the rest.

Use the sort as a filter. If something hasn't been worn for two seasons, it is unlikely to be worn next winter. Pass it on, sell it, or turn it into cleaning rags. What remains should be clean, repaired, and genuinely worth the space.

Choose Breathable Bags Over Bin Liners

Black bin liners and sealed plastic sacks are the single most common mistake. They trap any residual moisture with the fabric, and in a warm loft that becomes a breeding ground for mildew and a magnet for musty smells.

• Cotton and linen storage bags let air circulate while keeping dust off. Look for drawstring or zip closures the moths cannot crawl through.
• Cotton pillowcases are a cheap alternative for jumpers and scarves; tie the open end with string.
• Vacuum bags are fine for bulky duvets and pillows in a genuinely dry loft, but think twice with wool, cashmere and delicate vintage pieces — compressing creases can become permanent, and any damp gets locked in.
• Never use dry-cleaner polythene for long-term storage; it is designed for the journey home, not for months in a loft.

Crates, Labels and a Layout That Works

For anything that could tempt a mouse, a rigid crate with a fitted lid is your best defence. Clear crates let you see what is inside at a glance; line the base with a clean cotton sheet and pack items loosely, without cramming. Air needs to move around garments, so do not compress them.

Label every crate on the short end with masking tape and a marker: contents, sizes, season, and the date. Store heavy crates at the bottom of the stack, and keep everything off the bare joists and away from the roof underlay, where condensation drips. Simple timber battens or an old pallet give you a gap underneath and let air move. Leave a clear walkway to the hatch, and keep a torch within reach.

Guard Against Moths, Mice and Mustiness

Cedar blocks are a traditional favourite and genuinely useful when used properly — the oils deter moths, but they fade over time. Sand the blocks lightly every few months and replace them annually for them to keep working. Tuck them between folded layers rather than just on top.

• Lavender sachets add a pleasant scent and some protection; keep them wrapped in tissue so the oils do not mark fabric.
• Silica gel sachets help in crates but need refreshing — the little beads stop working once saturated.
• Skip mothballs. The smell lingers for months and the chemicals are not kind to fibres, children or pets.
• Check your loft twice a year for droppings and gnaw marks. If mice have found a way in, deal with the entry point rather than just the evidence.

Bringing Clothes Down Again

A week before the season turns, bring the relevant crates downstairs and let everything air in a well-ventilated room or in the shade outdoors for a day. Inspect seams and folds for larvae cases or fresh holes, then wash or dry-clean woollens before wearing — the heat also kills anything you might have missed. Give the empty crates a wipe, check the cedar blocks, and write next year's date on the label. A little care at both ends of the season is what keeps a loft full of clothes wearable rather than replaceable.