Wednesday, October 26, 2011

Pictures of pitching


Gavin Rose a National Trust ranger and expert trail maker taught people about the technique of 'pitching' at the close of our two week bridge building workshop .

Pitching creates a cobblestone surface along the walking surface of a bridge or trail.
In this case the anchor stones are dug in and secured at the approaches to the bridge and then stones are set deep into the ground and laid in rows up and over the arc of the top of the structure.


Its a slow process but the finished stone path ends up being a very durable surface providing lots of traction.


The courses of stones all have to have level faces running across the width of the bridge between opposing copes the entire length of the bridge. They are supported by carefully placed hearting packed and shimmed underneath each stone.


Here's a picture of everyone who pitched in, pitching at a feverish pitch, yesterday.


 Here is a pitcher perfect section of completed surface.

Today we finish the bridge and clean up the site.
(Lots of pictures of the completed Little Long Lake Bridge workshop tomorrow.)

3 comments:

  1. A finely tuned pitch!

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  2. How does the pitching follow the curve of the bridge? How do you set benchmarks?

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  3. Gavin writes

    "If you had been here John you would have learned the secret."

    Anyway basically a lot of the pitching question is answered in a previous post March 29 2011 'Hand Pitching' where he writes. ..

    To get an even surface I used a a simple technique that I learnt in Mallorca, Spain where pitching has been used for thousands of years. At the start of my pitching, at the down hill end, I placed a board across the road at the height I wanted the final surface of stone to be and placed another timber board cross the road at the other end of were the section of pitching would end - using a spirit level to get each board level. With the two boards in place either end I could then use a third board, with one end resting on the downhill board and the other end on the uphill board to determine the final surface of the pitching in between.

    The bridge is little more complicated but basically you take your benchmarks off the copes on either side which are all bedded level perpendicular to the direction of the path over the bridge.

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