[header] How to choose a commercial roofer [title] Interview potential roofers in person. [substeps] Proposals from different roofing businesses will vary greatly in price. This doesn't necessarily mean, though, that roofers submitting low bids will not complete the project as well as roofers submitting high bids. 
You will need to discuss the project in person with each roofer. For about an hour, discuss the project and ask questions.