Garden room windows and doors: choosing the glass

Glass is the part of a garden room you notice most and pay most for. It decides how light the room is, how warm it stays, how it looks from the house and, in summer, whether it is usable at all after lunch. Here is how to choose.

Sliding, bifold or French doors

Sliding doors

Two to four large panels, one or more of which slide behind the others. The frames are slim, so the view is wide and uninterrupted even when the doors are shut, which is most of the year. They do not swing into the room or the garden, so furniture can sit close. For most garden rooms they are the best all-round choice.

Bifold doors

Panels that fold back concertina-style to open almost the whole wall. Wonderful on the twenty days a year when it is warm enough to fold them all back; more frame on show the rest of the time, because every panel has its own. They cost a little more than sliding doors of the same width.

French doors

A pair of hinged doors, often with fixed side panels. The most affordable option, and in keeping with traditional houses. The frames are wider, and the doors need space to open.

Fixed glass

Large fixed panes, without opening sections, give the cleanest look and the best insulation for the money. A single tall fixed window framing a tree or the house can be the best thing in the room.

Frames

• Aluminium: slim, strong, low maintenance, available in any colour. The usual choice for sliding and bifold doors. Make sure it has a thermal break.
• Timber: warm and traditional, especially in painted finishes beside period houses, but needs repainting or oiling every few years.
• Timber-aluminium (composite): timber inside, aluminium outside. Looks warm in the room, needs little maintenance outside, and costs the most.
• uPVC: the cheapest, with wider frames. Rarely the right look behind a period house.

Dark frames (black, anthracite, bronze) almost always look more considered than white.

Double or triple glazing

Double glazing with a low-emissivity coating and argon fill is the standard for garden rooms and performs well. Triple glazing improves insulation and sound reduction further, but adds weight and cost and slightly reduces light. It earns its place on north-facing glass and in rooms used all day in winter, such as offices.

Large panels and glass near floor level must be toughened or laminated safety glass, as building regulations require in critical locations. Every reputable supplier does this as standard, but it is worth checking.

Orientation and overheating

• North: even, cool light. Ideal for studios and offices. No shading needed.
• East: morning sun, cool afternoons. Good for most uses.
• South: sun all day. Needs a deep roof overhang, a canopy or solar control glass, or the room will overheat.
• West: strong low afternoon sun, the hardest to control. External shading or blinds are essential.

Solar control glass reduces heat gain noticeably, at a small cost in light and a slight tint. A roof overhang of 600 to 900 mm on a south face blocks high summer sun and still lets in low winter sun.

Security

Garden rooms often hold expensive kit and sit out of sight. Ask for multi-point locking on all doors, anti-lift devices on sliding panels, laminated glass on the lower panes, and locks that meet recognised security standards. A light on a sensor outside and an alarm sensor linked to the house add a lot for little cost.

Costs

Glass and doors usually account for a large share of a garden room’s price. As a guide, upgrading from French doors and a window to a wall of sliding or bifold doors typically adds £1,500 to £3,000 on a standard room, and frameless or very large glass moves a room into a higher price bracket altogether. Try different options in our cost calculator.

The garden rooms Harrogate homeowners are happiest with tend to have less glass than they first wanted, in the right places, rather than more glass everywhere.