Backfilling - BWT P-PSC Notice D'installation Et Conseils D'utilisation

12.

BACKFILLING

For flat base pools, start backfilling and filling with water simultaneously.
For pools with a diving pit, start backfilling as soon as the water level reaches the bottom of the
panels, that is, once the diving pit has been filled with water.
The initial bottom layer around the pool should be of some porous material (sand gravel) to provide
efficient drainage away from the pool walls. Sand should be used in this layer.
Backfill should contain as little clay as possible. Backfilling should be carried out in successive
layers 15 to 20 cm deep as the water level in the pool rises such that the pressure exerted by the
water is cancelled out by the pressure exerted by the earth.
As the successive layers of backfill are laid down, these should be tamped down either by walking
on them or using a rammer. The backfill may be slightly dampened before hand or may be wetted
while it is being shovelled into the excavation. Damping or wetting improves the tamping and is
recommended if a deck is to be built soon after the installation of the pool.
To prevent breaks in the deck caused by the settling of the backfill over time, lay the deck on pillars
(concrete blocks laid head to head) or piles spaced at intervals of 2.50m around the periphery. The
pillars or piles are built before backfilling is started. The deck concrete slab should be 'cut' every 3
m before the concrete cures.
However, we recommend that you wait several months after the pool has been filled before
installing the deck. This is the time necessary to allow settling of the backfill.
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2020/05 - Indice de révision : B - Code : 37101 PISCINES P-PSC