[Greenbuilding] tennis court surface material

[Speireag Alden]

Sgrìobh Corwyn:

>The court requires some maintenance, dragging and rolling
>in the spring, sweeping after use, spraying with water during dry
>times, removal of rocks (every year, explain that!),

     They're down in the clay, and every year they get pushed up by 
frost action, mainly in the spring, when the surface is thawing, and 
therefore permits them to move upward, while a few inches down things 
are freezing and thawing daily or weekly, moving things up slightly, 
then permitting a bit of water to sink down on top of the frozen 
section, whereupon the water freezes and moves things up slightly, 
and so it goes.

     If the court stays in use for hundreds of years, I suppose it 
might eventually run out of rocks in the moving zone (five feet down, 
roughly, where you are).  But I wouldn't bet on it.  :)

-Speireag.

-- 
Anger, if not restrained, is frequently more hurtful to us than the 
injury that provokes it.
--Lucius Annaeus Seneca, philosopher (BCE 3-65 CE)