With over 170,000 views on Flickr, Calvin Seibert’s creations are admired by the world. But what drives one man to spend 10 hours painstakingly building a brutalist sandcastle, only for it to be swept away by the sea or destroyed by drunks? We spoke to him about how a hobby that began at art school turned into a lifelong passion.

How long have you been making the sandcastles?

I grew up in a small town in Colorado that in the 1960's was undergoing constant growth. My childhood home was surrounded by construction sites where I would play. There was a lot of scrap material to make things with and sand piles to play in. I had seen the Eero Saarinen TWA terminal in New York and was inspired to make swooping shapes in the sand. So my sandcastle building dates back 50 years.

The TWA terminal in New York

What's your background? Are you an architect or craftsman?

When I was young I kind of assumed I would become an architect. It was only as I grew older that I realised my interest, while very grounded in architecture, was really about art, and sculpture in particular. Many of the "buildings" I made as a child more closely resembled construction sites with their concrete foundations and initial wood framing rather than finished architecture. Looking back, what I really had been making was sculpture. In 1979, I moved to New York and attended art school. About that time I started going to the beaches in and near the city.

What inspired you to make them?

I like making things and tend to work with whatever is at hand. Building sandcastles at a beach to me is a very natural thing to be doing. As a child, I saw photographs of the French ski resort of Flaine. I was very taken by the brutalist buildings, designed by Marcel Breuer. Since then I have always gone out of my way to see brutalist architecture and when I build sandcastles I have them in mind.

Do you plan the designs beforehand or make them up as you go along?

I do make sketches throughout the year, but it is rare to have a completed castle actually resemble a sketch. A sandcastle for me is a kind of study or sketch in itself. I am pretty much making it up as I go along because it’s more fun not knowing. It would be real work if I tried to stick to a plan.

What happens when the tide comes in? Do you feel sad when they disappear?

The tide comes in, but so does a hot dry wind, seagulls, children and drunken louts. It goes with the territory and I'm happy with that.

How long do they take to build?

The smaller castles take 3 to 4 hours. The larger ones take all day, about 10 hours. On the right beaches, they can still be there the following day and I often add to them. It is best not to touch a sandcastle that has dried out so I construct new parts surrounding the old.

Do you use any specialist equipment or is it just a bucket and spade?

A five-gallon paint bucket is essential. Paint buckets are particularly rigid and have a nice sharp edge for digging with. Then it is used for carrying water. Lots and lots of water. The tools are all made of plastic. I have a couple that are nothing more than a small rectangle of 1/8-inch plastic with a beveled edge and then a couple of trowels of different sizes.

Where do you make them?

In past summers I took a train to Jones beach which is outside New York. Lately, I have been going to beaches I can reach by subway, like Coney Island and the Rockaways.

Thanks Calvin.