Research and significance assessment of the last Strutt mill building at Milford.

One building, or two joined together?

The list entry records that the dye house is said to have been built in 1832. The interior does not sit comfortably with a single date. The columns stand off centre, the plan is irregular, and the walls are not quite parallel.

We compared the 1839 tithe map, Ordnance Survey editions from 1880 to 1946 and a fire insurance plan of 1911 with the building as it stands, overlaying the existing plan on each, and consulted the Strutt estate records at the Derbyshire Record Office. Our reading is that the surviving building is an amalgam of two earlier structures, set at a slight angle to one another, which were joined and remodelled in 1856, a date cast on one of the columns. On that reading, the 1832 date belongs to a different dye house on the site, since demolished.

Iron columns, brick vaults and what they tell us.

The fabric supports the documents. Some of the cast iron columns are of an early square-edged pattern and may have been reused from elsewhere in the mill complex. Blocked openings mark former gangways between buildings. The walls show repeated alteration in stone and in brick.

That analysis sorted the building into what is most sensitive and what is less so. The iron frame and the brick vaults are the heart of its significance and of its contribution to the World Heritage Site. The external walls, altered many times, are more robust. For a building of this kind, that distinction is the foundation of any decision about its future.

A significance assessment as a design tool.

The proposal that prompted the work was for a veterinary practice, a use that needs enclosed rooms, washable surfaces and a good deal of ducting. We worked with the architects and the services engineer to fit those needs around the significant fabric. Partitions were set behind the column flanges so that the columns remained on view, suspended ceilings were confined to the clinical rooms and kept off the vaults, and a duct run was moved outside the building so that nothing passed through the brick arches.

The council concluded that the internal subdivision of the building, together with the other alterations, would harm its special interest, and that there were no public benefits to outweigh that harm. The applications were refused in March 2025. That is the nature of buildings of this sensitivity: some uses fit them more readily than others, and the purpose of a significance assessment is to make that clear.

The research does not depend on any one scheme. An account of how the Dye House developed, and of which parts of it carry its significance, is the starting point for any proposal that follows.