Cold Garage in Winter, Oven in Summer? Here’s the Fix

If your garage or outbuilding is too cold to use in January and too hot to stand in come July, the building envelope isn’t doing its job. Garages, workshops, garden rooms and outbuildings across Leeds are often the last space to get any thought during a build, bolted on with a single skin of blockwork and a felt roof and nothing else. That’s fine if the space is only ever storing bikes and paint tins. It’s a different matter if you’ve converted it into a home gym, office, workshop, or overflow living space.

Garage and outbuilding insulation brings these spaces up to a usable standard — stopping condensation on the walls, cutting the temperature swings, and making the room genuinely comfortable to spend time in. For homeowners across Leeds and West Yorkshire treating their garage as more than a storage box, it’s one of the better-value jobs we do.

What’s Actually Involved

Most garages built in the last fifty years have solid or cavity block walls, a timber or concrete roof structure, and little to no insulation anywhere. Heat moves through all of it — walls, roof, and often the up-and-over door too, which is usually just a sheet of uninsulated steel.

We treat the building as a whole rather than picking one surface. Depending on what we find during survey, that typically means:

• Spray foam to the roof underside — closed cell or open cell foam applied directly to the rafters or roof slates from inside, sealing gaps that batts and rolls always leave behind.
• Wall treatment — closed cell foam sprayed onto block or brick internally, or insulated plasterboard fixed over a treated wall where headroom is tight.
• Floor consideration — not always practical to insulate retrospectively, but we’ll flag it if it’s a major heat loss route.
• Door and opening treatment — advice on insulated garage doors or draught sealing around existing openings, since this is often the single biggest gap in an otherwise well-insulated garage.

Spray foam works well here because garages and outbuildings are usually irregular — sloped roofs, exposed purlins, odd corners around a chimney breast or old flue. Foam expands into those gaps in a way that rigid boards and mineral wool rolls can’t. We use BBA-approved products only, which matters because it means the material has been independently tested for a garage or outbuilding application and carries the certification a surveyor or building control officer will actually recognise.

Who This Is For

• Garage conversions — turning the space into a home office, gym, or bedroom, where Building Regulations Part L thermal requirements will apply.
• Workshop owners — anyone spending hours at a bench who’s fed up working in a coat.
• Garden rooms and outbuildings — timber-framed structures where damp and cold are pushing occupants back indoors.
• Anyone storing anything moisture-sensitive — tools, materials, or a vehicle you don’t want sitting in a damp, uninsulated space over winter.
• Landlords or homeowners adding usable square footage to a property without a full extension.

We get a fair number of enquiries from people who’ve had a garage conversion done years ago on the cheap — stud walls and plasterboard with nothing behind them — and now want it doing properly.

From Survey to Finished Room

1. Free survey — we come out, measure the space, check the roof structure, look for existing damp or ventilation issues, and discuss what you’re using the space for.
2. Specification — we recommend which surfaces need treating and which foam type suits the structure, and give you a written quote with no obligation to proceed.
3. Prep work — clearing the space, protecting anything staying in situ, and checking for any existing damp that needs addressing before foam goes on, since foam should never be sprayed over a damp problem.
4. Application — spray foam applied to roof and/or walls by our trained team, usually completed in a day for a standard single garage.
5. Ventilation check — we make sure the space still has adequate airflow post-treatment, particularly important in garages storing vehicles or where moisture generation is likely.
6. Sign-off — you get written confirmation of what was installed, the product specification, and your guarantee documentation.

What You’ll Gain

• A usable space year-round — no more writing off the garage for four months of winter.
• Lower condensation risk — insulated surfaces run warmer, which cuts down on the damp patches and mould that plague untreated garages.
• Noise reduction — a welcome side effect for anyone running power tools or a home gym next to a shared wall.
• Energy savings — if the garage is heated at all, even background heating, insulation cuts what you’re paying to maintain a usable temperature.
• Added value — a properly insulated, converted garage adds more to a property valuation than a cold, damp one that’s clearly just storage.
• 25-year guarantee on the installed foam, giving you a long-term record of what was fitted and by whom — useful if you ever sell.

What It Costs and How Long It Takes

Pricing depends on the size of the garage or outbuilding, the roof pitch, and whether we’re treating walls as well as roof. As a rough guide:

• Single garage roof only: roughly £800–£1,400
• Single garage roof and walls: roughly £1,500–£2,500
• Double garage or larger outbuilding, full treatment: roughly £2,500–£4,500

These are indicative ranges — the only way to get an accurate figure is a site visit, since roof pitch, access, and existing condition all move the price. The survey itself is free and comes with no obligation. Most single garage jobs are completed in a day; larger conversions with wall and roof treatment can run to two days.

Get a Free, No-Obligation Survey

If your garage or outbuilding is costing you a usable room every winter, get in touch and we’ll come out for a free survey — no pressure, no obligation. We’re open seven days a week, 9am to 7pm, across Leeds and West Yorkshire, and as one of the few local contractors who both install and remove spray foam, we’ll give you a straight answer on what’s right for your building rather than a one-size-fits-all quote.