Rebuilding Diary

The string of buildings that form the Maltings, Kiln and Mash House at Annandale Distillery are built on split levels with the west elevations at the higher level and the east elevations at the lower level. At some point during the Johnnie Walker era (circa 1900), the 'New Mill' was built at the north end of these buildings, sharing a common wall with the Mash House. Although the New Mill would have been somewhat out of sequence (ideally it should have been sited between the Kiln and the Mash Tun), this position would have allowed the mill to draw power from the pre-existing water wheel and steam engine (mentioned by Alfred Barnard in his book, The Whisky Distilleries of the United Kingdom, published in 1887). It transpires that the foundations of the New Mill were formed just below the higher level (mentioned above) and therefore are rather shallow in comparison to the lower level of the Mash House.

In the new set-up at Annandale, our mill will be sited in the Maltings between the new malt bins and the Mash Tun. This has allowed us to use the 'New Mill' as our Still House (hereafter referred to as the 'Still House') and otherwise to put the process in proper sequence. To do this, we need to create a 'cellar' beneath the Still House to a depth of over 3 metres, in order to accommodate the still bases and associated pipework. Creating this sub-structure posed a significant engineering challenge for our structural engineer (John Addison).

In simple terms, John's scheme required our contractors to create a special type of beam underneath the existing, rather shallow sandstone foundations of the gable end of the Still House. This type of beam is known as a 'Pynford beam' because of the very special procedure through which it is constructed. Once the Pynford beam is formed, piles are sunk deep into the ground beneath the beam to support the structure above (i.e. the Still House sitting atop the Pynford beam).

The process of forming the Pynford beam is interesting. To begin with, the contractors had to undermine the foundations at a few selected points to create gaps spaced relatively far apart. Each gap is about 0.5 metres in length and 0.5 metres deep. Prefabricated, four-legged steel stools are then carefully inserted into each gap to support the wall above. The foundations are then undermined in between the first batch of steel stools and further stools are inserted. This process is repeated until the entire structure is resting on these little (but very strong) stools.

Steel reinforcing bars are placed between the legs of the stool to the full length of the beam in each direction, leaving lengths of steel sticking out at each corner. Shuttering is formed around each of the outer sides of the beam and across the ends, to enclose the stools and the reinforcing rods. Concrete is then poured into the shuttering and thus the Pynford beam is formed.

At the time of writing, the Pynford beam is curing. Under-pinning work to form the cellar is scheduled to begin during week commencing 30 January 2012.