A roof measuring app gives a roofing contractor the facets, the pitch and the eave, ridge, hip and valley lengths from satellite or aerial imagery before anyone climbs a ladder, and the best roof measuring app is the one whose report matches the tape when the crew arrives. Roof measurements from satellite free, or from a free roof measuring app, are enough for a first count; a paid report adds a verified pitch and a diagram the customer can be shown. What no app measures is the tear-off layers, the decking, the flashing details and the access, which is why the app feeds the takeoff and the estimate template on this site prices it, with waste, hours at a loaded rate, overhead and markup.
What the imagery gives you: area, pitch and the lines
A measuring app reads the roof outline from imagery and returns each facet's area, its pitch where the imagery supports it, and the lengths of the eaves, rakes, ridges, hips and valleys. Those lines are what the accessories are counted from: starter and drip edge by the eave and rake, ridge cap by the ridge and hip, valley metal or membrane by the valley. The total area in squares with a waste factor for the roof's cuts is the shingle count, and the app has done the walk on the roof for that half of the takeoff.
What the imagery cannot tell you
How many layers are on the roof, whether the decking is sound, what the flashing at the chimney and the walls looks like, whether the ventilation is adequate, how the trucks will get in and where the dumpster goes. Those come from the ladder and the attic, and they move the estimate more than a few squares of area do. A free app's area is worth what it costs; the site visit is where the money in the estimate is decided.
From the report to the estimate
Enter the squares with waste, the accessories by the foot and the piece, and the tear-off and disposal from the site visit into the estimate template on this site as the material line; add the crew's hours at a loaded rate, the equipment and the subcontracted work; the overhead and the markup produce the total. Pro keeps the estimate with the measurement report against the customer and the property, so the squares measured and the bundles used can be compared when the job closes.
Questions people ask about roof measuring app
Is a free roof measuring app accurate enough to bid from?
For the area and the lines, usually; for the pitch, the layers and the details, no app is, so bid from the imagery plus a site visit and treat the free report as the first count.
What does the best roof measuring app add over a free one?
A verified pitch, a diagram for the customer, and a report format the crew and the supplier can read; the accuracy on area is often similar and the difference is in the details and the presentation.
Can roof measurements from satellite replace the site visit?
No. The visit decides the tear-off, the decking, the flashing and the access, and those change the estimate more than the area does.