A large proportion of Douglas's buildings still exist, many of them being listed buildings, in a wide variety of types and styles. Douglas is not remembered for any one building type; his churches and houses are considered to be of equal importance. He was not a pioneer of any particular new development, but instead followed national stylistic trends while still retaining his individuality. His buildings are "anything but copyist" and they "bear a highly individual and nearly always recognisable stamp". The major characteristics of his buildings are "sure proportions, imaginative massing and grouping ... immaculate detailing and a superb sense of craftsmanship and feeling for materials". His work is "architecture which can be enjoyed as well as admired".