Whether the company is licensed and insured, and if their license is up to date. 

How much experience the company has, and what experience they have with similar projects. 

Whether the company can provide an estimate online and if they offer detailed estimates.

What local references or customer referrals that you can ask for 

What equipment do you need for the project, and do they know how to use it safely?

What safety procedures does the company has in place to protect their workers and your property.