Generally not. Rework is a business cost; resulting damage to other property usually is covered.
Labor Law 240 and 241 impose near-absolute liability for gravity-related injuries, so severity is much higher.
It extends your sub's coverage to protect you for claims arising from their work. It's your primary cost control.
On new construction and major renovation, yes. Confirm whether the owner is carrying it before you buy duplicate cover.
Yes, in practice. Collect certificates and require additional insured status before anyone starts work.
