# Forum Home Renovation Pools, Spa & Water Features  Pool concrete surround

## mickem

Hi,
ive recently had a fibreglass pool installed and it is surrounded by sand fill. I'm just after some advice as to how long I should allow the fill to settle before concreting so that the slab doesn't drop, and secondly should I put in footings for extra support?

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## pauljygrant

Our pool installer back filled with crusher dust and waited 2weeks for it to settle before returning to lay the concrete bond beam. During that time, we were asked to wet the crusher dust every night ( not to flood it) to encourage it to settle.  The fill material dropped a fair bit during that period. We are now 1 year on and I'm about to start the coping and then the pool area paving and decking. There are a few gaps under the bond beam where the fill has settled even more but the structural integrity of the beam remains. Will try to add more crusher dust / road base as I go.
my concern is whether sand would continue to wash out with rain?
as for time to wait, too long and the top of the pool might go out of alignment but too quick and the ground won't have settled. I'm guessing there is no exact answer and a lot depends on local ground conditions. Pool companies doing the whole job won't wait much time as they will want to complete and get their final payment ASAP.

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## r3nov8or

For two local companies around here the backfill of fibreglass pools is commonly crusher dust mixed with bags of cement, maybe 20 bags for the whole job, and the concrete beams are often poured within a few days of completion. I would have expected your concrete beam to have been part of the construction contract, but even if not the pool company would surely have a recommendation for their installation.

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