Calculating Repair Costs Virtually

[Jack Phillips]

Hi all! I'm new to Real Estate. I have some knowledge on how to give a rough estimate of repairs but I was wondering if any fix and flippers could tell me how they estimate repairs for a single family home virtually? 

*Some context* I cannot hire a contractor because I am a wholesaler and do not have enough time to send someone to look at the property or even ask for pictures. I will have a brief description of the condition of the property from the seller. I will have pictures after the homeowners signs the purchase agreement to send to the cash buyer.