The main theme of Bert's work is industrial and cultural heritage. Sources of inspiration for his paintings are abandoned and often ruinous buildings. He records these often before demolition by photographs and sketches. These are worked out in his atelier at the Vest in the historic city centre of Gouda.
Use of colour and use of light make his paintings special events. Dark disconsolateness is changing into light and warmth. Regularly he adds characters into his paintings who provide another or an extra dimension to the image. The tension in their relation is sometimes nearly tangible.
Besides the oil paint for the top layers he mostly uses acrylic paint as ground-colour or priming. In several paintings he has used gold foil, acrylic modelling and glazing gel.