You could sue the contractor for negligence for the damage to the automatic pool covering tracking system, stained plaster with concrete spilling into the pool and the damaged tile.  Negligence is based on the failure to exercise due care (that degree of care that in this case a reasonable contractor would have exercised under the same or similar circumstances to prevent foreseeable harm).In addition to the cause of action (claim) for negligence, your lawsuit should also include a separate cause of action (claim) for breach of contract based on the substandard work of the contractor and the resulting damage.Your damages (the amount you are seeking to recover in your lawsuit) should include the cost of repairs and cost of replacing the damaged track.  You will need to mitigate (minimize) damages by replacing the damaged track with a track that is comparable and not the most expensive one you can find.  If you were to select the most expensive track you could find as a replacement, your damages would be reduced accordingly.