Standard Installation and Backfill Requirements for concrete tanks

Alberta Wilbert Sales Ltd. recommends that any of our concrete tanks that are installed be set on 6” inches of level washed sand or ¾” washed pea gravel, placed on an undisturbed soil base. The earth from the excavation can be used as backfill. We suggest that any large rocks or frozen lumps of clay be removed prior to backfilling.

***IMPORTANT*** "No tank should be left empty between October and March; a minumum of one (1') of fluid depth should be placed in the tanks to prevent the ground under the tanks from freezing and heaving a tank, increasing the risk of cracking".

1. Set base into prepared excavation level as above, clean groove of tank with wire brush and dust, dry with torch if needed.  Set tape provided into groove overlap rolls by 4 inches.  Set top sections lining up edges carefully prior to setting down.  In cold weather allow 24 hours for tank to settle. You may backfill prior to this but do not use tank.

Tamping or mechanical compaction is not recommended around the tanks and is not allowed on top of the tank. Compaction may void warranty. Standard settling is the usual method of compaction, and causes no damage to the tanks. Mounding of the backfill to allow for some settling is suggested, but most often re-grading will be required.  If compaction is required then we recommend that sand be used to backfill.

These practices are all recommended to maintain the integrity of the tank. Any external connections to the tanks are also protected from possible shearing or breaking.

If tanks are to be load bearing (i.e. vehicles driving over the tanks)  then they should be ordered as such and backfilling around the tanks should be in 6” lifts of a self compacting material such as washed sand, pea gravel around and on top of tanks. A concrete slab must be poured (6” to 8” thick) with 15ml rebar 6” on center at final grade and must extend out 2 feet on the width and length of the tank. Any roller compaction (non-vibrating)  should remain 5’ away from perimeter of the tank.

If the tank is to be placed on a concrete slab, then 6” of washed sand or 2” of stryofoam must be placed between the concrete slab and tank.  NEVER PLACE CONCRETE ON CONCRETE.

Consult your product sales representative for any questions.