Designing a cool garden room
When designing their garden room, most self-builders we talk to are concerned that their room is going to be warm enough to use in winter. With forecasters suggesting that hot summers as we are experiencing this year, will become the norm. We also need to think about designing a room that will be cool space in hot weather. Luckily, the multi-layer build up and the combination of insulation in the floor, walls and roof mixed with double glazing, which ensures a warm garden room in winter, will help keep the space cool in summer.
There are, however, a few design elements that you could incorporate into your garden room, which will help keep it cool in summer.
Create a cross flow of air
Getting air moving around your room is a good way to keep it cool. This can be achieved by positioning doors and opening windows on different walls. We have this in our own garden room an can confirm that having doors open on two walls, creates a nice cooling flow of air. You could achieve the same thing by having your doors on one wall and an opening window on another.
Having doors and windows on different walls can create a cross flow of air in the room.
Casement windows are easy to open and let in a good amount of ventilation. They are not the most fashionable choice at the moment in garden room design. Instead, designers are choosing to use top hung, rectangular windows.
These windows come in varying widths and depths. 1200mm wide is about the widest example we have seen and 300mm high the shallowest depth. You have to be careful if choosing a very small, opening rectangular window because you can end up with more frame than glass!
Rectangular opening windows are a useful way of letting air into the room. They can be positioned high in the wall or at desk height.
Rectangular windows like this offer you flexibility over positioning. They look equally good positioned at desk height, as they do positioned high up in the wall. Often, garden room designers will suggest positioning a window like this high in the wall if the view the other side isn’t great, for instance, if it overlooks a hedge or fence. Even with a poor view, they are an easy way to let air flow into your room.
Design in some natural shading
Part of a garden rooms charm is the amount of glazing you can incorporate into the room. The natural light they let into the room is a real benefit, except at the height of summer, when the sun is at its highest. There are ways you can defuse this intense high summer light, but not compromise it entering the room during the rest of the year when you will be glad of it.
Venetian blinds are an easy way to diffuse the light entering the room.
Adding blinds to your doors and windows is an easy option. Typically Venetian blinds are used. The cheapest way to add them is to fix them to the back of the door frame, but they can be bulky when pulled back. Higher end garden rooms will have the blinds fitted within the double glazing. This is a sleek option, and you control the position of the blind using a magnet. Ask your door and window supplier about your options of having blinds fitted within the glazing, it is a pricey option, but it is a great way to discreetly control the light entering your room.
Designing at deep eaves detail on your roof is another way that you can break up the high summer light entering your room. When the sun is at its highest, the eaves break its journey into your room, casting shadow. The clever thing is during the winter when the sun is low, and we want as much of it entering our rooms as possible, the eaves detail does not block its passage.
Deep eaves can cast shadow when the sun is at its highest and hottest in the summer. Yet, they don’t block out light during the winter.
This principle can be exaggerated by adding a deep veranda along the front of your building. The roof canopy again breaks the journey of the sun entering the room when it is at its highest and hottest. A veranda also can create a shady seating area. Enhancing the inside-outside qualities of a garden room.
A veranda along the front of the building can also cast shadow. They also provide a shady inside-outside seating area.
As we have shown in this illustration, you can incorporate a louvred screen into a veranda design. In practice, the examples we have seen used in garden room design are more decorative than practical! For a fixed screen like this to pay its way, you would need to think about the orientation of your room and the time of day that it would be diffusing the light.
Louvred screens could be a useful alternative to blinds if you could easily move them. In principle you could fit screens to a sliding door track and slide them along the wall as and when you wanted to diffuse the light. Ideally, you would use a system where you could tilt the fins.
As you can see, these are relatively simple design features. Mixed with your highly insulated core structure, they could have a big impact on the usability of your room.