Tuesday 11 December 2012

Herringbone pitching at Aira Force

After finishing our fencing job at Stickle Ghyll we've spent much of our time repairing a section of footpath over at Aira Force. We'd already moved all the materials, by helicopter, earlier on in the year, so it was just a matter of getting ourselves and our tools to site.

Before starting work
Before starting work

As you can see in the photo above, the original path has become quite badly eroded. It's also right next to a steep drop, so it was decided that we should create a new path further to the right and landscape the old path to blend in with it's surroundings.

The first job was to move the slate from the helicopter drop site to where it was required. We used our mechanical power barrow to make things a bit easier and it wasn't long until we had enough stone to work with.

The rock now moved to site
The rock now moved to site

As we wanted to be able to secure rock for any future work (and there's a lack of quality pitching stone in the area) we decided to use slate rather than stone gathered from the fell. Aira Force is also a more formal environment than our usual places of work so we thought that we'd use a slightly different technique, known as herringbone pitching, that would be more in keeping.

The path starts taking shape
Starting the new path

Basically, the path is created by a series of courses (similar to that of a drystone wall), with the slate sunk depth-wise into the ground. The first course ends with the the last stone a little higher out of the ground than all the others (this will be the start of the next step). The next course ends with two stones higher, the third course has three stones higher and so on. After a while you're left with a series of triangular steps as you can see in the photograph below.

Herringbone pitching at Aira Force
Herringbone style pitching

It's almost as difficult to build as it is difficult to explain, but eventually once we all started to get our heads around it, the path really started to take shape.

Completed section of path

The first section completed

Once all the stone work was done it was time to start on a section of gravelled path.

Line of the gravelled path
The line of the new gravel path

Firstly a tray to contain the gravel was dug out. All the soil removed was placed on the old footpath and the turf kept to one side to be used later on in landscaping the process.

Digging out the trench
Digging off the turf

Once the digging was finished it was time to start gravelling. The plan was to move the gravel in our "trusty" power barrow but after prising it off the frozen ground with crowbars it decided it didn't want to start so we moved all the gravel (about 6 tonnes) by hand. This was done by a combination of carrying it in rubber trugs and dragging it onto the path in the helicopter bags that were used to fly it to site.

Gravelling the trench
Starting gravelling

Eventually all the gravel was moved and and the gravel path was joined up to the stone footpath.

Finishing gravelling
Finishing off the gravelled path

All that was left to do was to landscape the old path with rubble, soil, boulders and turf so that walkers would now instinctively take the new route.