While your CAR insurance policy will cover you against any accidents or damages as part of the project, it might also be worth taking out additional insurance to ensure you’re protecting against any unforeseen issues or problems that occur off-site related to the project.
This might include taking out goods in transit insurance to protect against any damages while moving equipment, it would also be worth checking on van insurance/fleet insurance in case of any accidents or breakdowns.
You might also consider taking out public liability insurance to protect against any potential accidents or injuries involving members of the public around the site.