He also studied for three years at the Atelier Masqueray, the first independent architectural atelier in the United States, founded by Franco-American architect Emmanuel Louis Masqueray.
Van Alen a lucrat de asemenea timp de trei ani, pentru Atelier Masqueray, prima firmă independentă de arhitectură din Statele Unite, care fusese fondată de arhitectul franco-american Emmanuel Louis Masqueray.