In 1992, the modernist architect Mart van Schijndel designed a house in Utrecht with a number of distinctive features. When he died in 1999, his widow, Natascha Drabbe, an architectural historian and public relations executive, was determined to open the house to visitors. But she also needed to continue to live in the 1,885-square-foot building. For advice, she began reaching out to the directors of other important 20th century houses, from Frank Lloyd Wright’s Fallingwater to Mies van der Rohe’s Villa Tugendhat. Soon the directors were sharing ideas and strategies, and Drabbe had founded the Iconic Houses Network. In November, the organization, which she runs from her office in Amsterdam, will hold its biggest meeting yet, at Gaudi’s La Pedrera-Casa Milà in Barcelona; participants will have a chance not only to discuss important 20th century houses (with a focus on the Mediterranean region), but to visit some of them, as part of a pre-conference tour program.

How did the Iconic Houses Network begin?

I was working in Mart’s office, and we ended up in a relationship. He had just completed this house, which is on a difficult site. It has no windows to the outside world, and yet it makes amazing use of natural light. And there are other innovations, like doors that swing on silicon sealant, not hinges. 

And then?

We’d been in the house for seven years when he became seriously ill. When he died he was 56, which is way too young, for anyone, and for an architect especially—he was still creating a body of work. My whole future with him was gone. I kept on living in the house, and trying to get my life on a new track. At the same time, I wanted to keep his work alive.

What did you do at first?

I set up a foundation, we then applied for grants and developed a website about his oeuvre. And this year we did a book about the Van Schijndel House. I had each person involved—writers, graphic designer, and photographer—spend at least 24 hours in the house.

Why 24 hours?

It’s important to see the ways Mart used light and color, which change over the course of the day. I thought everybody working on the book should experience that; I couldn’t just explain it to them. 

Did you set up a foundation?

Yes, but I can’t afford to donate the house to the foundation. I have to live somewhere. So I began researching houses like mine, to find out how they were organized. After four years, I had a database with more than 100 houses, and I realized that we might benefit from a network.

Who were some of the people who helped you?

Among others, Susanna Pettersson, the director of the Alvar Aalto Foundation; Iveta Černá, one of the founding members of DoCoMoMo; and Lynda Waggoner, the director of Fallingwater. They have been great teachers.

What did you learn from Lynda?

That you have to be creative. I would have thought that if you’re restoring a house, you can’t expect people to pay to see it. But when Fallingwater was being restored, Lynda put a glass wall between the workers and where the visitors stood. People paid extra money to follow the restoration.

When did you officially form the network?

We launched in 2012, at the Schindler House in Los Angeles. Our first European symposium was at the Victoria & Albert Museum in London last November.

What’s the biggest problem facing these houses?

It’s always money. Especially money for maintenance. Architects usually support these initiatives, but at least in the Netherlands right now, architects don’t have a lot to give. Another thing is, these houses have neighbors, and you have to find way to get the neighbors on your side.

Are there particular maintenance issues?

A lot of these houses were designed by architects not for wealthy clients, but for themselves. They wanted to show what they could do, architecturally, but they didn’t have huge budgets, so often they experimented with unconventional materials. You have to deal with these materials, sometimes finding substitutes that work.

What kinds of problems do you have at your house?

The oven doesn’t work, but I don’t want to replace it with an oven that isn’t of the period. So right now I can’t cook for my friends. But if I put in the latest model, the house won’t be the house anymore. 

That’s a great attitude.

If you choose to live in a house that’s architecturally important, it’s a crime to change it. If you don’t like it, look for another house. As the owner of one of these houses, I know you have to suffer a little bit. 

What are some of the houses people can see as part of your conference?

The Casa Gomis (La Ricarda) is a serenely beautiful example of a Catalan rationalist house by mid-century architect Antonio Bonet Castellana. It’s near the Barcelona airport; the family can’t live there any longer, because the airport expanded and the planes make so much noise. And they can’t sell it, for the same reason. So they give tours and ask for donations. But its future is very uncertain. We will also visit Casa Masó in Girona, by Rafael Masó, who was very relevant to the development of modern architecture in Catalonia, and the Palau Güell, by Gaudí, which only recently opened to the public.

I have been to the Palau Güell, and it’s amazing.

There’s another house by Gaudí, the Casa Vicens, which was the first private residence he designed. It’s owned by a bank, which is restoring it. It will open in 2016.

The Palau Güell is literally a palace.

But the Iconic Houses Network is not just about houses for the wealthy. It’s also about housing. We have about 10 apartment museums on our website. In Barcelona, there’s a tiny apartment in Casa Bloc, by Josep Lluís Sert and others. It’s been restored, and the Design Museum of Barcelona gives tours. And there are apartments at Le Corbusier’s Unité d’Habitation, in Marseille, where the owners will give tours.

It sounds like you’re particularly interested in houses that are occupied?

Houses that aren’t lived in can feel soulless. At least 10 of our houses are still lived in, including houses by Richard Neutra, Jean Prouvé, Arne Jacobsen, and Paul Rudolph.

And of course Mart van Schijndel!

Yes. And I think they’re some of the most interesting houses, because they challenge conventional perceptions of “public” and “private.” Visits to these houses give you a look into the lives of the owners or tenants, and that can be exciting.