A garden room can add valuable space and increase your property value — but there are several practical decisions to make before you start. Here's what to think through first.
What Will You Use It For?
The intended use of your garden room should drive every other decision. A home office has different requirements to a gym, a studio or a games room. An office used year-round needs good insulation, heating and fast broadband. A gym needs ventilation and durable flooring. A hobby space may need extra power sockets and lighting. Being clear on the purpose before you start avoids expensive changes later.
Size and Positioning
Consider how much space you actually need, not just what fits in the garden. A room that is too small becomes frustrating quickly. Think about natural light — south or west facing positions get the most sunlight, but heavy summer sun through glazing can overheat the space without shade or ventilation. Also consider the view from the main house, privacy from neighbours, and the distance you'll be walking from the back door in bad weather.
Insulation Is Not Optional
If you intend to use the garden room throughout the year — including winter — insulation is essential. A poorly insulated room is expensive to heat and uncomfortable to work in. Look for insulated panels or frames with insulation between the structural timbers in the walls, floor and roof. The higher the insulation value (measured in U-values), the cheaper the running costs. Don't let a supplier skip this — cheap upfront usually means cold and costly year-round.
Foundations and Ground Conditions
Most garden rooms are built on timber frame supports, concrete pads or screw pile foundations. The right choice depends on your garden's ground conditions, slope and any tree roots nearby. Timber bearers on concrete pads are common and cost-effective on flat ground. Screw piles are faster to install and better suited to sloped or unstable ground. A good installer will assess your specific garden before recommending a foundation type.
Electrics, Heating and Broadband
Running power to a garden room requires a dedicated cable from your consumer unit, buried underground in conduit to a safe depth — typically 450mm under a lawn or 600mm under a drive. This must be carried out by a qualified electrician and notified to building control. Consider how many sockets you need, whether you want underfloor heating or a wall heater, and whether you need a data cable run alongside the power. Getting this right first time avoids the cost of digging up the garden later.
Budget Realistically
Garden room costs in Hertfordshire vary significantly depending on size, specification and finish. A basic insulated timber room typically starts from around £8,000–£12,000 supply and install. Mid-range rooms with quality glazing, electrical installation and internal fit-out typically run £14,000–£22,000. Premium bespoke structures cost more. Always get a detailed written quotation that specifies what is and isn't included — particularly electrics, foundations and internal finishing — before committing.