Back in the days when I was still a roofing contractor I spent a big part of my day measuring jobs for re-roofing. By the time I drove to a location, inspected the roof, and measured it I could spend a lot of time. Now days of course there are several different satellite measuring services that are very helpful. Their accuracy is typically very good and they give you a lot of very excellent information. This service usually costs somewhere between $60 and $90 and well worth the money. Obviously there is some information you can’t get from these services. For example, you can’t tell whether there are multiple roofs that need to be removed, whether ventilation is adequate, or whether the decking has problems.
There is another service that you can get for free if the job is an easy roof, you’re in a hurry, and only feel like you need to be reasonably close in your estimate. Here’s how:
Get on your computer and pull up Google Maps. In the lower left-hand corner there is some text that says “maps labs” which you should click on. When the Google Maps Labs Screen pops up enable the Distance measurement tool. Once it is enabled press save changes. With that done you should pull up an address of a house in Google Maps. Then you should zoom into the location as far as you can. Down in the left and corner of the map there is a little ruler. Click on the little ruler and then you can click on one spot and when you click on another spot you have a measurement. Make sure you have the measurement in feet and not meters.
I’ve checked this on a few houses and found this technique to be reasonably accurate. You can get a street shot by clicking on the little man and that lets you determine whether you think the roof is walkable or not. Whether you’re measuring for a designer roof or another material, I certainly wouldn’t rely on this technique for all jobs, but in a pinch it is useful.