Mill Valley by Field Theory

When the time came to transform this mid-century home into a modern sanctuary, interior designer Leah Harmatz of Field Theory was determined to preserve its treehouse spirit. Nestled among the redwoods in California’s Marin County, the artfully-decorated residence honors the original architecture and uses locally-sourced natural materials to create an effortless connection from interior to outdoors.

Photography Margaret Austin

Your designs often emphasize creating a strong connection between the built environment and the natural world. Why do you think this is so important as a designer?

I think there’s a distinct happiness that people experience when spending time in nature, but often the tendency is to settle in at home. If I can find ways to make that connection between the built environment and the outside world, I feel like people are more at peace in their space. Whether it’s by adding large windows that bring in natural light, incorporating organic materials and sustainably crafted pieces or simply styling a room with plants, making these connections between interior and exterior has a transformative quality. I know I’m preaching to the choir here, but I think we have a responsibility, as designers, to tread lightly. Our work has such an impact on the natural world, for better or worse, and I try to take that responsibility to heart.


What inspirations were on your mood board for this project?

I was inspired by the mid-century Marin architecture of the home – the exposed wood beams, vaulted cathedral ceilings and large windows framing the redwoods outside. We referenced a lot of modern Bay Area architecture, and Japanese and Scandinavian lighting and furniture. I was also inspired by our client’s beautifully curated collections of handcrafted studio ceramics, original art and design books. When we first met, there was an immediate design kinship. Throughout the project, it was so enjoyable to be able to have that seamless dialogue and shared aesthetic with her – it felt like a true collaboration.

The Mill Valley residence is described as "a magical treehouse in the redwoods." How did you reference the natural surroundings in the decor? 

Every time I drove up to the project through the redwoods for a site visit, I would instantly feel calmer, almost as if entering another world. We wanted to reflect and celebrate, rather than compete with, the natural surroundings. The design palette tended towards greens, browns, and muted clay and earth tones; colors that can all be found in nature. The textures and finishes also feel complementary to the exterior, with mostly matte surfaces, including natural woods, clay and woven fibers such as wool and linen.


The house was originally built in 1974. What were some of the historical features you sought to preserve? Where did you seize the chance to contemporize the home?

We wanted to preserve the original windows in the living room with fir trim, the vaulted ceiling and the brick fireplace. The previous owners had done a basic builder grade remodel before selling the house, and we wanted to bring back some of the original mid-century magic. We added natural wood built-ins and sculptural light fixtures that are more in-keeping with the architecture of the home. All the windows were replaced with double paned to increase energy efficiency. We reconfigured and renovated the kitchen and living spaces to make them more conducive to our client’s love of cooking and entertaining. We opened the kitchen up to the dining room, and added an island and a custom-designed floating white oak banquette and breakfast table.

"There’s a distinct happiness that people experience when spending time in nature."

The relationship between form and function is always a key consideration. How did you navigate the push and pull between these two elements?

It was actually quite easy to align form and function in this project. Our client is particularly thoughtful about the way she moves through the world; everything has an order and purpose, and felt very intentionally selected for the space. As an example, we designed integrated wood pulls on most of the custom cabinetry because it has a very simplistic and beautiful look, and it is also extremely functional and durable.


How did you make the indoor-outdoor flow feel so seamless?

We added fully opening glass sliding doors between the dining room and exterior deck, literally creating a seamless flow to the outdoors. The deck has its own zones for living and entertaining, with a firepit, an outdoor sectional sofa, and my favorite – a heated sofa for chillier nights and foggy mornings.

Tell us about some of the natural and sustainable materials that you integrated into the remodel.

We wanted to use natural materials from the surrounding area as much as possible – ceramic tiles from Heath made at their factory just down the road in Sausalito, locally handcrafted white oak millwork and concrete countertops from a maker in Marin.


We were delighted to spot some of our rugs in this project. What considerations are front of mind when you are choosing a rug for a room?

In thinking about rugs for a room, I always narrow it down based on function, first and foremost. Where is the rug being placed, and what sort of daily activities does it need to support? Then I’ll consider the aesthetics of the space, and the color and texture to layer with all the other elements. A rug is truly the foundation of a room. It serves to delineate the space and tie everything together. It felt like the perfect fit to include Armadillo rugs in this project (and really most projects I work on!), because there is such a beautiful and natural feel to them, an attention to craftsmanship and alignment with our ethos.

Your client has amassed a delightful collection of art, photography and other treasures. What were some of the pieces you chose to showcase?

Ceramics by Sarah Kersten, vases from Julie Cloutier and Zoe Dering, artwork by Rob Wilson, Marta Johansen and James Tucker, a vintage Heath casserole from Alameda flea market, a vintage Chez Panisse Poster by David Goines (another Alameda flea market find that I reframed, featuring my client’s birthday month – the restaurant's anniversary), and a Simone Bodmer-Turner vase. These are all Bay Area finds.

And a couple of others that are not as prominently featured in the photos but special to my client – sculptures by Joe Wheelwright and Peter Haines, both close friends of her parents.


What do you hope the homeowners will experience every day as they interact with the space?

My hope is that the homeowner experiences an enveloping feeling of comfort and ease in her home. It is so deeply personalized and customized to feel like a refuge in her daily life, and I hope all of the design details, small and large, bring a daily sense of joy.