How do you install it?
Surface dressing involves either single surface dressing or double surface dressing over a prepared surface, such as a sub base, worn Tarmac or Asphalt. If applied directly to a sub base, two layers of surface dressing are required to make a durable surface. On top of an existing worn Tarmac or Asphalt surface, one layer of surface dressing is adequate.
Before laying surface dressing, treat the new sub base or existing worn Tarmac or Asphalt surface with weed killer – weeds may break through the thin surface and crack it. Use a residual weed killer subject to environmental considerations.
Surface dressing quality depends on the evenness of the surface that it will be applied to. It is important to specify a surface regularity of a maximum gap of 10mm under a 3m straight edge with no high or low points or hollows. If possible, use a drag box to lay the sub base to achieve an even surface. If the sub base lacks sufficient fines to provide an even surface, blind it with a dust. If ‘as dug’ or recycled aggregates are to be used to build the sub base, regulate with 50mm depth of Type 1 to provide a strong, even surface that is suitable for laying the surface dressing on.
Before use, loose stone chippings must be swept from the finished surface. Loose stone can cause a slip hazard.
Here is a useful link of a detail drawing