So how many bricks are in the chimney? Funnily enough we don’t know an exact number. The chimney is built with multiple thicknesses of brickwork at the bottom. As the chimney gets higher, the number of thicknesses decreases as the chimney tapers. Our best guess, using various calculations is that there are about120,000 bricks, the combined weight of the chimney is around 500 tons.
What sort of bricks were used? Although we can’t be certain, we are fairly sure that they are Accrington bricks or Nori. These are a very strong, iron hard engineering brick, famed for their strength and are reputed to have been used in the foundations of Blackpool Tower and the Empire State building no less!
What sort of brickwork does it have? If you look at the brickwork in the picture you can see that for four rows, the bricks are laid using a stretcher bond, then with one row of headers. This looks similar to the “English Garden Wall” bond, where there are a row of headers after every three courses of stretcher. This type of brickwork gives a lateral spread of the load and uses fewer facing bricks than other styles. (www.designingbuildings.co.uk)
Why has the chimney got bands around it? As far as we know, the chimney has been banded since it was first built. This is to add strength to the chimney. Those of you who have lived in the area long enough will know that the chimney now has more bands than it did originally. This is because in 1999 Fred Dibnah came to work on the chimney. He came primarily to repoint the chimney and to paint the bands. While on site, he added extra bands, between the ones that were originally there, and also the decorative iron girdle at the top of the chimney.
(If you visit the mill on a Steaming Day, you can see a display of pictures which were taken by one of our volunteers of the view from the top of the chimney.)
What mortar is used for industrial chimneys? In a lot of constructions a concrete mortar is used, this is generally satisfactory although over time, the bricks can begin to spall. For this reason, on chimneys like this one, a lime mortar is preferred. This helps to preserve the brickwork, by wicking the moisture away from the bricks themselves.,
If you have any questions about the chimney or anything else to do with the mill, please email us at info@bancroftmill.org.uk