How to Calculate the Cost of a New Gambrel Roof

Locate and print off a remodeling cost spreadsheet from an online source or obtain one from a local building contractor.

Measure the square footage of your top floor using a tape measure. Look at pictures and plans of homes with gambrel roofs to determine how high or steep you want the pitch of your roof to be.

Research the cost of lumber and other needed building materials such as hardware, shingles and siding by visiting online remodeling websites or local home repair stores. Use your square footage calculation and projected roof pitch to determine how much material you will need. Enter this information onto the spreadsheet.

Contact the local government agency that supervises zoning and building permits to determine the need for and costs of building permits and inspections. Enter this information onto the spreadsheet.

Contact local building contractors if you don't plan to do the building yourself. Obtain an estimate for projected labor costs and potential additional expenses. Enter this information onto the spreadsheet.

Determine if you will need to do duct work, electrical or plumbing remodeling due to the roof construction. Obtain the necessary estimates for this work, and enter these figures onto the spreadsheet.

Add all the figures listed on the spreadsheet for a preliminary estimate total. Add an amount for unexpected costs such as $500 or $1,000 depending on how accurate and thorough your research has been. You may feel more comfortable with the overall estimate if you give yourself a large cushion for unexpected expenses. Add the preliminary estimate total to your unexpected cost amount for a final estimate total.