How do you find rafters on a slate roof?
On thin slate, open Rafter Finder, place the phone flat, calibrate, and scan along the batten (usually about a third of the way up a slate). Two or three local highs in a vertical line mark the rafter. No tile removal required.
What is Indicator 1 used for on the Rafter Finder app?
Indicator 1 shows a LIVE figure. You’re looking for the local high. Always scan along the batten (usually about a third of the way up a slate) to find the batten or rafter nail. Two or three local highs in a vertical line — that’s the rafter.
What is Indicator 2?
Indicator 2 is a confidence indicator. Scan the area first so it records the data, then the confidence bar hits 100% when it finds that area’s local high. Best when you already know roughly where the nail is and want to pin it down.
What is the device calibration?
Calibration tells the app where the sensor is in your phone, so it can show the sensor’s position on screen while you scan.
Do stud finders work on a roof?
Not reliably. Covering density and the air gap under tiles or slates break wall-oriented sensors — including many expensive radar units.
Can you find rafters without going in the loft?
Yes. On thin coverings like slate, the free app scans from outside. On some thicker free jobs you may place magnets from the loft once, then scan outside. Pro is meant to work from outside on every covering.
Does the free app work offline?
Yes. You don’t need internet on the roof for scanning.
What about Cambrian interlocking slate?
Cambrian-style thin interlocking coverings usually work with free direct scan — no magnets needed.
When should I choose Pro?
When you need every roof covering — thicker concrete, stone, heavy slate, multi-layer — or you want AR overlay and dedicated sled hardware. Free remains the right tool for thin coverings like slate.
Still stuck? Visit Support or register Pro interest.