Knowle Mill

Knowle Mill is a former worsted mill complex dating from 1906-8 and 1926, designed by the Keighley architects J. B. Bailey and Son. The buildings are constructed of coursed gritstone with blue slate roofs, with the exception of a chimney and joiners shop which are of red brick.

The complex is arranged with two multi-storey spinning mills aligned end-to-end on a north-south axis, the 1908 mill to the north and the 1926 mill to the south. Attached to the rear (east) of the north mill is a north-lights weaving shed of two phases, trapezoidal in shape due to the constraints of the site. A former engine house lies to the south of the shed at the central point between the two spinning mills, with a boiler house alongside to the south. A free-standing chimney stands further south of the boiler house. To the west, an entrance building and a red brick joiners shop are positioned alongside the main entrance.

The north mill is four storeys plus basement with seventeen bays in length, set beneath a hipped double-span roof of six bays depth. The main entrance sits at the southern end of the west elevation, with a line of taking-in doors in the adjacent bay to the north. Ground, first and second floor windows are tall with multi-paned glazing, plain cills and lintels and linking binder blocks below the window heads, while third floor windows are squarer. An external privy tower with narrow lancet windows marks the north-west corner. The north elevation features a line of taking-in doors with an external fire escape on the rear bay of the front roof.

The south mill is similar in character, with its main entrance adjacent to that of the north mill. The three bays containing the two entrances and taking-in doors are topped by a dentilled parapet carrying the name KNOWLE MILLS in serif capitals. A further line of taking-in doors appears at the southern end of the west elevation. The south elevation is dominated by a combined stair, hoist and privy tower occupying most of the building's depth. Window details and other features otherwise match the north mill.

The weaving shed is joined to the north mill by a covered passage with a glazed roof and has a single storey with a basement that becomes a full lower floor towards the southern end. The south elevation has an entrance and large ground floor and first floor windows, with a projecting bay to the right containing two narrow windows to each floor.

The engine house lies between the shed and boiler house with only its east elevation visible. Its gable end contains an entrance to the right with a large multi-paned window above, and external iron steps lead up to a large first floor window and entrance to the left.

The boiler house projects slightly further east than the engine house. Its lower half is rendered with a narrow doorway to the right, and the gable above has two narrow windows. The south elevation has two roof lights and a raised section adjoining the spinning mill with a small window; a garage entrance sits below.

The chimney has a square section, tapering with a moulded cornice and draught cone.

The office building on the south side of the main entrance is a small structure with a steeply pitched asbestos roof, probably originally an entrance lodge but itemised as a shop in 1985. Its northern side has two three-light windows. The east gable end contains a recessed doorway to the right and a half-glazed vehicle entrance to the left extending beyond the main roof line. The south side has a raised section to accommodate the vehicle entrance.

The joiners shop is a two-storey red brick building with a monopitch roof facing east, identified in 1985 as a joiners or engineers shop and by the current owner as a fire house. The main east elevation has two wide vehicle entrances with wooden half-glazed doors and a central door. Three wooden-framed multi-pane windows occupy the first floor, with a single window on the south side together with a first floor entrance. A brick chimney stack rises from the centre of the south elevation.

Within the north mill, the main entrance at the southern end leads to a concrete dog-leg staircase with iron hand rails descending to the basement and ascending to upper floors. Adjacent to it are a hoist and the space formerly occupied by a rope race powered by the engine house to the rear. Each of the four floors has a central row of cast iron columns extending along the centre, supporting timber beams and joists. The columns have square section bolting heads for former line shafting. The third floor is open to the double-span roof structure, which features timber king-post trusses with iron tie-rods. The basement is divided by later partitions and contains cast iron columns without bolting heads.

The south mill's interior is almost an exact mirror image of the north mill, with the entrance and staircase at the northern end. The basement is in two parts: the northern three bays have cast columns without bolting heads, possibly constructed at the same time as the earlier mill, while the remaining sixteen bays are taller with cast columns with bolting heads supporting steel joists and a concrete floor.

Within the weaving sheds, the timber-framed north-light roofs supported by a central run of cast iron columns remain on the main floor. The lower floor has columns supporting steel joists beneath a timber floor. The interior is now partitioned and used as office space.

Modern breeze-block and stud partitions in the weaving sheds and office are excluded from the listing as they are not of special architectural or historic interest. The interiors of the engine house and boiler house were not accessible for safety reasons, and the joiners shop interior was not inspected.