One of the ways that significant parts of our heritage can be protected is through the listing process of Historic England (further details here).
Duck houses form part of the ephemeral heritage of country house estates and can often be overlooked. The medieval style duck house at Hedingham Castle in Essex floats in one of the lakes created in 1720. It deliberately evokes the 12th century castle keep in the estate.
Such an unusual feature stands alongside scheduled duck decoys (e.g. Peterborough).