Question: how many square feet does 1 gallon of flex seal cover?
Answer: so you will need approximately 20-40 cans of Flex Seal Aerosol. However we have Flex Seal Liquid that comes in Gallons each gallon covers approximately 150 square feet and depending on how thick you roll or pour it you will need 3-5 gallons on your Shop roof. | 1 of 1 found this helpful.