Most garden purchases are reversible. A garden room with glazing or glass pergola is not. It alters how the house looks, how the garden functions, and how the two relate to one another. Get it right and it becomes one of the most loved and utilized rooms of the home. Get the specification wrong and it’s either too hot in July, too cold in November, or it’s leaking at the roof junction in five years. The difference is made by decisions (often the right ones) made before anything is physically ordered.
This section deals with glass pergolas, independent garden rooms, and glazed structures that are a midpoint between a conservatory and an open outdoor room — i.e. they are weatherproof and usable all-year-round, and are designed to be connected to the garden rather than sealed off.
A glass pergola is a lighter construction option compared to a fully enclosed garden room. It features fixed posts, and an aluminum or timber frame, and a fully glazed roof, which can be either flat or pitched. Some systems offer motorized louvres instead of solid glass, which allows for better ventilation control during summer. The best quality installations have built-in drainage channels located within the frame sections. This is an important detail. A glazed roof with poor drainage will have ponding water at the joints. Wet joints will ultimately fail regardless of how well the joints were sealed initially.
Differences in quality are most pronounced when it comes to the selection of glass. The absolute minimum for overhead panels is toughened safety glass, while laminated glass is the better option for roofs because if it breaks, it will not drop in dangerous fragments as opposed to toughened glass. They are also better for overall safety and comfort. Even though laminated glass is more costly, its low emissivity coatings help to provide a more thermally comfortable environment that will not make the space unusable during the winter or the unit an oven in the summer. Bargain-priced glass creates an environment that is thermally comfortable for only a short period during the spring and autumn.
Garden Rooms
Building a standalone garden room is a big commitment. It will require you to do proper groundworks like a concrete slab or ground screw system; a level, stable base, and a plan for electrical provision, which is a foundation-type decision (not retrofittable). Planning for retrofitting lights and heating will be more disruptive and costly than planning for them beforehand.
Most installers will recommend aluminium frames, and for good reason. Thermally broken systems, where there is an insulating barrier between the inner and outer frame sections, prevent cold bridging and the condensation problems that follow. Your powder-coat finish will be durable and come in a wide variety of colours. It is true that timber frames will suit the design of some properties better architecturally, but the maintenance requirement is genuine and shouldn’t be underestimated.
When a garden room is attached to the house, there are two areas that require special attention. These are roof flashing and the threshold between the indoor and outdoor flooring. When it comes to improper installations, these are the areas that water typically enters. Any reputable installer should be able to speak to how they address these two issues.
Planning permission
Most of the time, planning permission won’t be necessary for garden rooms, as they usually meet the requirements for permitted development. The only exceptions to this are conservation area locations, listed buildings, and structures that are additionally oversized (to certain thresholds) or are boundary line adjacent. It’s a quick call to your local council (typically 5 minutes) and it’s worth your time.
The articles in this section explore these types of structures in more detail — what to specify, what to ask the installers, and where the common issues tend to arise.