Date published 14-04-1956, text also in English. This article describes the newly completed extension of the Bouwcentrum (exterior photos, interior photos, construction photos, site drawings, sections, floor plans, preliminary studies, functional floor plans) in Rotterdam by architect J.W.C. Boks and his associate architect H.O. Eckardt. The article focuses on the construction (detail drawings, cross sections skeleton) and the mixed concrete-steel skeleton of the building. Also part of the article is devoted to the brick relief by sculptor Henry Moore on the Weena facade and shows images of the other artworks in and on the Sgraffito by artist Dick Elffers (photos); Steel composition by artist J.G. Schilthuizen (photo); hard stone sculpture by sculptor Piet Stuyvenberg (photo); limestone sculpture by J.A. van Vlijmen (photo) and a mural by artist Greta Rikko (photo). Also many illustrations of the interior (photos) and the permanent and changing exhibitions (photos). Illustrations: situation, exterior photos, scemas, floor plans, sections, architectural drawings, photos of construction phases, interior photos/Building center on Weena in Rotterdam, arch. Boks Design years: 1957 (front)