[Russell Cissell]

That depends on if you are estimating or guesstimating.

Square foot is the surface area of the wood that you have to restore and preserve. If you are going to clean it and seal it, you've got to count it. It would take a lot of time to precisely measure the exact square footage of surface so most contractors use some degree of guesstimation.

It is common for example to take the length of the hand rail times it's height to determine the actual surface area. This is not exact, but it is typically very close. You can take it to the next degree and just add six (6) foot to any side of the deck that has a rail. For instance a 10 X 10 deck with a house on one side would be calculated as 16 X 22 for a total of 352 square feet. By adding six foot to each side you pick up the area of the rail and the band board around the outside of the deck.

The closer you are to the actual surface area, the better able you are to estimate your material usage. It also helps you to track your material costs.

Estimating time is the other side of the coin. It is important for you to determine material usage but surface area it relative to the actual time on the job. It's hard to even type this without thinking about how much I hate handrails. Obviously if you are not spraying, an equal amount of handrail surface area is going to take much longer than the wide open surface area of a floor. If I were going to plug a number in I would say rail area warrants a factor of 1.5 or more If the floor takes an hour, the rail will take another hour and a half or more.

Now finally you have to think about bidding. Once you have figured out how long it will take and how much it will cost you in materials, it's easy to set a price. This difficulty comes in presenting that information to your customer in a way they can accept. Sure, sometimes you can just say "I figure it'll be about $1,400.00 bucks" and they will jump right on it. If you don't want to catch yourself back peddling at the closing table, you should also be prepared to make them understand the "why" of your price if they should choose to challenge it.

The more detail you can collect for yourself, the better able you are to monitor your business. The less information you have to give your customers, the easier it is for them to understand your price. For instance, IMO, you may explain that the rails take longer than the deck the deck, that's simple to comprehend. You would not want to give them a lesson in calculating complex surface areas followed by your formula for calculating the price.