Measure the length and width of each section of the deck. Include the length and width measurements of stairs and calculate the square footage to arrive with a rough estimate of the amount of deck stain you need. The amount of stain you need depends on the type of stain you use. For example, one gallon of Messmer's TimberFlex deck stain covers between 75 and 100 square feet.
Consider the cost of the deck stain in regards to how much stain you require for the project. Messmer's TimberFlex deck stain costs $39.99 per gallon. If you must stain a 500-square-foot deck, you will need at least five gallons for a total of $199.95, plus tax. You have to charge significantly more than this amount to make your money back.
Determine the cost to clean and repair the deck before staining. You must have the deck pressure washed, sanded and repaired before staining, and this process alone costs between 50 cents and $2 per square foot. You may perform this service or hire a professional deck cleaner to help.
Estimate the amount of time you require to clean and stain the deck. Instead of thinking in terms of hours, think in terms of days. Each day you work on the deck is time away from another job, so you want to make sure that you make enough each day to cover the amount of income you require daily.
Combine the estimates of both supplies and services and deliver this estimate to the homeowner as your bid. Ensure the homeowner that this bid represents an estimate and not an exact number in case you incur unexpected fees or higher prices when purchasing supplies.