Technically, this small building is not a tree house, since it’s braced at the ground by supports, but Grey didn’t want to compromise the tree, which “doesn’t have a very long lifespan,” the designer says. “So, I didn’t want to jeopardize however long that tree had with any excess baggage.”

The sinuous interior is lined with CNC-cut wooden panels that define stepped sauna seating and porthole windows.

The sauna structure includes a small deck.

A 25-foot custom bifold door made of corrugated plastic and twin-wall polycarbonate encloses an artist’s studio designed by Marc Frohn of FAR frohn&rojas.

The ribbon-like design affords the building three different gable profiles—one is symmetrical, while the other two lean in opposite directions.

Rose’s pottery studio opens right up to the back lawn to let the sunlight (or curious pups) inside.

A wood-burning stove from Harvia, of Finland, heats the sauna. The pavilion’s rough-cut pine walls are treated with tar, a preservative that yields a time-worn aesthetic.

Phillips designed Judith a stark white, glass-fronted art studio.

We tried to be very resourceful. You shouldn’t see any tile on the deck that had to be cut; it’s almost like a perfect puzzle,” comments the designer, Marc Frohn.

The sauna is named after Huginn and Muninn, two ravens from Norse mythology.

The structure is made entirely from treated pine, while its corrugated polycarbonate roof protects it from the elements.

The Exbury Egg asks us to reexamine the way we live while carefully considering sustainability and the use of natural resources.

These tiny egg-shaped cabins are mounted onto small podiums to keep them stable.

The sauna door handle is a simple piece of driftwood. “One principle rule I followed,” says Kiehl, “was: Don’t build on outdoor space if it can work as outdoor living space. Norwegian summers are short. We want to be outdoors as much as possible.”

Fir plywood from Freres Lumber joins IKEA cabinets. The figure painting is by Dylan Dean.

This room can be a family room, office, or guest suite. The flooring is the same throughout: Riva Floors, Engineered Wood Select Grade, in Crystal Thunder, and the couch is from Restoration Hardware. Unseen is the foosball and ping pong tables.

This dreamy, glass bedroom by the lake was created as an early prototype for the prefabricated greenhouse/she kits known as the Kekkilä Green Sheds.

Helsinki architect Ville Hara and designer Linda Bergroth collaborated on a prefab shed-meets-sleeping cabin, which can be assembled with little else than a screwdriver. Bergroth, inspired by nomadic yurt dwellers, wanted an indoor/outdoor experience for her property in Finland.

The curved wall is just as pleasing of a detail when experienced on the inside of the writer's studio.

The concrete wall behind the porch provides a backdrop for the wood stove and privacy from the road.

A bathroom is tucked beside the new sunroom behind the sliding barn door, which was found at Albany Architectural Salvage.

A guest bedroom, with furniture from Room & Board, overlooks the bridge above the dining courtyard. The home’s landscape architecture is by Ventura, California–based Jack Kiesel. Photo by Coral von Zumwalt.

The screened porch functions as the building’s primary bedroom, creating a cabin-like experience.

A small, dilapidated 10' x 12' neighboring structure was brought back to life and is now used as an art studio and guest cottage with a Murphy bed. In total, the property can sleep 10 people comfortably.

Marco V. Morelli says his Studio Shed is the perfect refuge. “It’s changed my life for the better,” he says. “I’ve gotten so much more work done, and I think my marital relations are much better because I have a place of my own.”

The bi-level car barn, a spare, timber-clad structure with an A-frame roof, nods to traditional farmhouses, but is “sleek and contemporary in spirit,” says Geremia. Inspired by an old photo of a porcelain farmhouse sink, it features polished concrete floors.

Inside, playful pillows can be rearranged in any manner, and are often used as mock beds for relaxing and looking at the canopies above.

Each shed is customizable via a recently launched interactive online tool and range from $120-150 per square foot. With more people working from home, backyard offices offer a physical barrier between life and work, this one in Walnut Creek, California, has a FullLite glass front elevation.

Working with his colleagues at Austin Maynard Architects, architect Andrew Maynard added a 184-square-foot, sun-saturated greenhouse extension to his existing 364-square-foot home, and the new space serves as an office for him and his team.