What to store in a garage, and what not to

A British garage is a cold, damp room with no thermostat

The question of what to store in a garage has a different answer in Britain than it does in the American articles that dominate search results, because the garage is a different building. Ours are single-skin brick or block, uninsulated, unheated, often with an unsealed concrete slab and an up-and-over door that seals nothing. The temperature inside tracks the weather outside with a lag, and the air is damp for most of the year.

Two things follow. First, anything that is damaged by frost will be frosted at some point between November and March, and anything that is damaged by heat will cook under a metal roof in July. Second, every time a mild wet day follows a cold night, warm moist air meets the cold walls, the cold slab and every cold object in the room, and condenses on them. That is the film of water on the car in the morning, and it is on everything else too.

So the sorting rule is simple. Things that do not mind cold, damp and swings between the two can live in the garage, and most of what a garage is for passes that test. Things that do mind belong in the house, and putting them in the garage is not storage, it is slow disposal with a delay of one winter.

What a garage is good at storing

Tools, above all — hand tools on the wall, power tools on a rack, with the one caveat on their batteries covered below. Garden equipment, the mower, the strimmer, hoses and the kit that is used outdoors anyway. Bikes, on a wall mount that swings them flat when the car is in. Tyres, out of sunlight and off a wet floor. Ladders, folding furniture, the roof box, the pressure washer once it has been drained.

Hardware and consumables that come sealed: screws and fixings in bins, cable, pipe, timber off the slab on bearers, tiles, bagged compost, road salt. Sports kit that is plastic or metal. Empty suitcases. Boxes of things that are genuinely inert — the spare kitchen tiles, the old car parts, the offcuts. All of it is happier on shelving than on the floor, and all of it copes with a winter.

The common thread is that none of it contains water it needs to keep, a chemical that separates when it freezes, a cell, a circuit board, or a fibre that holds moisture. If an item passes that test, the garage is fine for it, and the only question left is whether it goes on a shelf, a hook or the floor. If it fails, read on.

What the cold and damp will ruin

Paint is the one people learn the hard way. Water-based emulsion and most wood paints, primers and varnishes are ruined by a single hard frost: they separate, go lumpy, and do not recover on warming. The same is true of PVA glue, wood adhesive, most sealants and fillers, and anything else that is a liquid held in suspension. A garage in winter is exactly where a half-used tin of the right colour goes to die.

Electronics and anything with a battery in it are next. Condensation forms inside a cold device as readily as on the outside of it, and lithium cells left through a winter near freezing lose capacity and do not like being charged cold. Spare cordless tool batteries, the old laptop, the games console, the spare phone — indoors. Paper, photographs and documents absorb the damp and grow mould. Soft furnishings, mattresses, cushions and clothes do the same and add the smell.

The ones that are a safety question, not a storage question

Petrol, diesel, spare fuel cans, gas cylinders for the barbecue or a heater, and a spare bottle of LPG are the items people ask about most, and the ones this guide will not give a quantity for. How much fuel you may keep at home, in what kind of container and where, is governed by law. What your insurer will cover if something goes wrong is governed by your policy. Both should be read before anything flammable goes into a garage, and neither should be taken from a forum, including this one.

The reason it matters more in a garage than in a shed is that most British garages are integral or attached. They share a wall, and often a ceiling, with the house. A fire in a detached shed is a lost shed; a fire in an integral garage is a house fire. Fuel and LPG vapour are heavier than air and collect at floor level, which in a great many garages is also where the boiler, the freezer motor and the tumble dryer are.

If you do keep fuel, the plain-words version of the rules is: a container made for the purpose, sealed, upright, away from anything that heats or sparks, in the smallest quantity you actually need, and within whatever limit the law and your policy set. Cylinder suppliers' own guidance is to keep gas cylinders outdoors, upright, valve closed, away from heat and away from drains, because the gas sinks. If that is not possible where you are, then your garage is not the place.

The things people are surprised by

The chest freezer is the one appliance people put in a garage on purpose, and it is worth checking. Not every domestic freezer is designed to run in an unheated room: each model has an ambient temperature range stated by its manufacturer, and one run in a room colder than its range can cut out or stop freezing properly. Look for that range in the manual before it goes out there, not after a winter of soft ice cream.

Wine does not like a garage, however cellar-like it feels. It is the swing that hurts — cold in January, hot under the roof in July — and a cork that has been through both is a cork that has let air in. Tinned food survives a mild winter and a hard frost can freeze the contents and stress the seam, after which the tin is a gamble. Anything a mouse can eat, including bird seed, dog food and grass seed, is a mouse invitation unless it is in a sealed bin.

Then the sentimental things: the box of photographs, the old vinyl, the guitar, the books, the wedding dress. None of these belong in a garage for a single winter. They go in the house, in the loft if it is dry, or they go to someone who has room. The garage is where things go when they are not worth a warm room, and it will treat them accordingly.

Making the garage better at the things it can store

For everything that does belong, the two enemies are the slab and the outside wall. Get boxes off the floor onto shelving — a freestanding boltless unit does it without drilling — and keep a gap between the shelves and a single-skin wall so air can move behind them. Anything that would rather not be damp goes in a lidded plastic box, not a cardboard one, and the box goes on a shelf, not on the concrete.

Hang what can be hung. Bikes on a wall mount, the hose and the extension lead on hooks, the ladder on brackets — all off the floor, all where air moves round them, all out of the puddle that forms by the door in a wet week. The garage will always be cold and damp. Storage that accepts that, and keeps things up and closed, works. Storage that pretends it is a spare room does not.