Crushed Stone Base Preparation for Playground Surface Installations
The construction of a crushed stone base for Tile playground surface installations is critical to the long-term durability of the playground surface. Particular size stoned and compaction rates are necessary. Completion of the crushed stone base to a specification is to be done in advance of Surface America’s crews arriving for installation of the Tile System.
The minimum depth of the crushed stone base is 4". Typical thickness range is 4” - 6”. Crushed stone base layers thicker than 6” are more challenging to achieve the necessary 95% compaction rate throughout the base. Thickness is never to exceed 10”.
The stone for the base must be crushed so it compacts to a 95% Standard Proctor Compaction (as per A.S.T.M. Test). The stones should be a homogeneous mixture of the following size stones:
Sieve Size % Passing by Weight
1" 90 - 100
5/8" 50 - 80
1/4" 30 - 50
# 4 15 - 35
# 8 10 - 30
# 30 3 - 5
#200 0 - 3
The crushed stone is typically flat but can also be sloped to allow the minority of water that does not enter the rubber to flow to a particular side or sides.
Tile Systems are extremely porous. Most of the water enters the system and must be able to percolate through the crushed stone base so puddling is avoided above the crushed stone base in the bottom layer of the tile.
The crushed stone base must be thoroughly compacted by using a tamper, roller, or a combination or both. This is of critical importance so that settling of the crushed stone base does not happen after installation of the tile. If post-installation settling occurs, of course, the Tile System will follow the contour of the settled crushed stone, leaving an aesthetically inferior installation and possibly causing the tiles to separate because of excess stress where the crushed stone base has settled out.
The tiles will reflect the levelness of the crushed stone base.
The crushed stone base must be a level plane that is smooth and comparable in look to the sub-surface of an asphalt road prior to the asphalt paving. This requires significant attention to accomplish. String lines must be used to ensure an even plane is constructed.
A filter fabric is necessary for crushed stone bases on when Tiles are installed. Typar 3401 or comparable filter fabrics are acceptable for Tile installations.
Any specific questions regarding crushed stone base construction are welcomed at Surface America.