Unbound surfaces

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Consider unbound surfaces where a formal path surface is required but a natural look is desirable.

Ideally lay unbound surfaces using a drag box to maximum depth of 25mm to seal the base layer from the ingress of water, protecting it from frost heave, and for even surface.

Always specify the tolerance of surface eveness for unbound surfaces - less than 5mm gap under a 3m straight edge placed along the path surface provides a smooth and even surface which will prevent puddles forming, and pleasant surface for all path users to enjoy safely.

New unbound surfaces tend to be soft until fully consolidated. If horse and bicycle use is expected allow a new path to consolidate before use (usually after the first fall of rain and some further pedestrian use).

Materials

As dug

A won surfacing material consisting of free draining, naturally occurring sands and rounded gravels with relatively high fines and clay content to bind the sand and gravel particles together when compacted with a roller. It is commonly sourced from on-site burrow pits along side the path under construction, or imported to site. As dug will bind well after plenty of rolling and forms a reasonable firm surface, but it can be very variable and its quality and consistency should be monitored when used.

hoggin

For best results, as dug materials should be sieved and graded to produce suitable sized material for surfacing which binds naturally together once rolled e.g. 6mm down.

Beware of as dug materials with a very high fines and clay content. If the fines content is too high, the material will go soft, rut and become slippery when wet. When considering any as dug material for path surfacing, check its suitability first. Click on 'testing the suitability of surfacing materials' to find out how to do simple surface materials test.

To find out more about as dug path construction have a look here.

For more information on the use of locally won as dug materials for path construction have a look at this case study.

Natural aggregate

Crushed whinstone, limestone or granite ranging in size from 6mm stone particles down to fine dust. Commonly used quarry aggregates are whin dust, granite dust and limestone dust, depending on availability and local geology.

whindust surfacing

To find out more about path construction using whin dust have a look here.

Specification
icon As Dug Path - Standard Detail Drawing & Specification Details
icon Whin Dust Path - Standard Detail Drawing & Specification Details
icon Granite Dust Path - Standard Detail Drawing & Specification Details

 

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