Moisture map with a moisture meter: from scattered readings to the direction of the source
You run the moisture meter across the wall, the numbers jump between 20 and 80, and you tell the customer “the damp is high here”. But where is it coming from, and from which direction? Scattered readings cannot answer that. An organised moisture map on an even grid can.
In this guide you will learn the correct grid method for a moisture meter, then use the Moisture Map tool in Kashf Pro: you photograph the meter's display at each square, the value is read automatically, and a heat map is drawn showing the highest point and an arrow towards where readings get stronger. Then you save a report for the customer.
What is the moisture map and what does it give you?
It is a tool in the Kashf Pro app that turns the readings from your own moisture meter into a grid of squares and then into a heat map.
You select a square and photograph the meter's display while it sits on that spot; the value is read automatically and stamped with the server's time. After two points the guidance appears: the highest point so far marked with ★, and an arrow from the current square towards the neighbour with the higher reading. When you save, you get a report link containing an image of the map.
Who is this tool for?
- Leak detection technicians who need to narrow the search area before listening or opening up.
- Waterproofing technicians who document the state of a ceiling or basement before and after their work.
- Damage assessors who want an organised record instead of scattered photos.
You need a moisture meter with a digital display, with or without pins.
When do you use it?
- For a damp patch with no obvious source: to learn whether it comes from above, from below or from the bathroom side.
- Before opening up: to choose an opening point at the edge of the damp nearest the source, not in its middle.
- After the repair: to repeat the map a few days later and prove the readings are falling.
- Before waterproofing: to make sure the surface is dry enough to apply the material.
Where do you use it?
- The lower part of bathroom and kitchen walls: where supply and drain pipes run.
- Ceilings below bathrooms or roofs: to find the direction of the source.
- Ground-floor and basement floors: to tell rising damp from a leaking line.
- Walls next to a ground tank or a planter.
What do you need before you start?
- A Kashf Pro account: a free trial once per mobile number, then a plan or usage credits. Limits are shown on the plans page.
- A moisture meter set to a single fixed mode for the material: plaster, concrete, wood or a relative scale.
- Masking tape or a pencil to mark the grid on the wall.
- A tape measure to keep the spacing even.
- Good lighting on the meter's display, and an internet connection for the automatic reading.
How to use it correctly, step by step
Moisture MapSubscription — free trial available
You start by choosing the reading unit (“Percentage %” or “Meter value” for a unitless relative scale), then the grid size: rows from 2 to 6 (3 by default) and columns from 2 to 8 (4 by default). You tap the square you are standing at, then 📷 Photograph the meter display.
The picture is read automatically on the server. A reading is accepted if the value is between 0 and 999 and the reading confidence is above the operator's threshold (75% by default). The value appears with a note about the mode or scale if one is shown on the display. An unclear picture gives you “📷 Retake” with the reason.
Each recorded square is coloured according to its value relative to the highest value. Below the grid is a smooth heat map interpolated between the squares, with a ★ on the highest reading.
The guidance compares the selected square with its eight neighbours. If a neighbour is higher, an arrow points to it with the size of the increase. If you are at the highest point, “You are at the strongest point — focus the search here” appears.
Steps for correct use
- Mark the grid on the wall first
Mark the area with masking tape and divide it into equal squares, for example 30 or 50 cm. Then choose the matching rows and columns in the app. Do not change them once you start, because resizing clears all readings, and the tool asks for confirmation before it does.
- Take a dry reference reading
Measure the same material in a dry spot away from the patch and note the number. This is the baseline you compare the whole map against.
- Select the square, then photograph the display
Tap the square in the grid, such as 1·1 for the first row and first column. Place the meter in the middle of that square on the wall with the same pressure each time, tap 📷 Photograph the meter display and take a clear picture of the screen with no glare.
- Follow the guidance square by square
After two readings the arrow and the ★ appear. Record the neighbouring squares in the direction of the arrow first, then complete the rest so the full shape emerges. If “Retake” appears, move the camera closer and remove the reflection.
- Save the map and share it
Tap 💾 Save map. The report contains the number of points, the highest value and its row and column, and an image of the heat map. Send the link to the customer or attach it to your report.
How to read the result
Colours and markers
- Coloured squares: the colour is relative to the highest reading on this map, not to a fixed threshold. A map that is all red may still be dry if all its values are close to the reference reading.
- ★ highest point: the highest reading recorded so far, with its row and column number.
- The arrow: from the selected square towards the higher neighbour. “No stronger neighbour — compare with the ★ square” means the selected square is a local peak and the real peak is elsewhere.
Reading the shape of the map
- A clear peak that falls away around it: the source is close to the ★. This is where you start listening or make a limited opening.
- A gradient from one edge: the source lies outside the grid in the direction of that edge. Extend the grid that way.
- A raised horizontal or vertical band: usually follows a pipe route or a structural joint.
- Even high readings along the bottom of the wall that fall with height: a pattern of damp rising from the ground or a leak in the floor, not a pipe in the wall.
- Values close to the reference in every square: the visible damp may be old and already dry, or superficial condensation.
The grid method: measuring damp so readings can be compared
The two types of meter
- Pin (resistance) meters: measure electrical conduction between two pins inside the material. Accurate in wood and plaster, but they leave holes and are affected by salts.
- Pinless (capacitance) meters: measure changes in an electrical field under the sensor pad to a limited depth. Fast and leave no mark, but they are affected by metals and by hand pressure.
Readings are usually relative
Many meters in concrete or masonry mode give a relative scale, not a true moisture percentage. The number is useful for comparisons within the same material using the same meter. So use:
- One mode for the whole map.
- One material: do not mix tile and plaster readings in one grid.
- Steady pressure and a perpendicular angle.
- A reference reading on the same material in a dry spot.
Sources of false readings
- Metals: nearby rebar, metal tile trims and copper pipes raise readings on capacitance meters.
- Salts: old walls with efflorescence conduct electricity more, which raises pin-meter readings.
- Surface condensation: a cold wall near an air conditioner can read high at the surface only.
Spacing between points
Squares of 30 to 50 cm suit most walls. Start with a wide grid that covers the patch and its surroundings, then repeat with a finer grid around the ★.
A worked example: a living-room wall next to a bathroom
A damp patch at the bottom of a living-room wall, with the bathroom behind it.
- You mark a grid of 3 rows × 4 columns with 40 cm squares; column 4 is closest to the bathroom corner.
- The reference reading on the same wall in a dry room: 18.
- The readings: third row (bottom) 35, 48, 62, 81. Second row 22, 30, 41, 55. First row 19, 21, 26, 33.
- The ★ is at row 3 · column 4 with a value of 81. Values fall as you go up and to the left.
- The interpretation: the source is at the bottom of the wall near the bathroom corner, meaning in the bathroom floor or its supply line.
The next step: a pressure test on the bathroom lines, and listening at the corner. The map saved you from opening the wall in the middle of the patch.
Common mistakes that spoil the result
- Changing rows or columns after starting: the tool asks first, and if you agree, the recorded readings are cleared and a new grid begins.
- Forgetting to select the square before photographing: the reading is written to the selected square, so it ends up in the wrong place.
- Switching the meter's mode between plaster and concrete during the map.
- Measuring over rebar, a pipe or a tile joint: a high reading that is not water.
- Uneven squares: the map draws equal squares, so the shape is distorted if they are not equal on the wall.
- Stopping at the visible patch: the source is usually outside it, so extend the grid towards the pipework.
- No reference reading: without one you cannot tell whether 40 is damp or normal for this material.
The honest limits of the tool
- Automatic reading needs an AI provider connected to the server. If none is connected, “Automatic reading is not available right now” appears and values are not recorded.
- Reading limit: each session allows 60 readings, and retakes count towards them. The largest grid (6 × 8 = 48 squares) fits in one session with 12 readings left for retakes.
- The tool does not know the material or the mode: it records the number as it is and shows it in the unit you chose (% or meter value). Interpretation is up to you and your reference reading.
- The arrow is local: it compares the square only with its neighbours and does not mean the source is necessarily in that direction.
- Interpolation between squares is an estimate: the smooth map fills the gaps mathematically and does not measure between points.
- A moisture meter measures close to the surface. A deep pipe can show damp some distance from where it is, once the water has spread.
- The result supports your decision and does not replace it.
When do you need to escalate?
You are the technician, but these cases deserve escalation:
- A second opinion from Kashf: the map points to a source outside where you can reach, such as a neighbour's bathroom, the roof or a buried line, or the damp does not fall after your repair. The Kashf team, which works in Saudi Arabia, inspects electronically without breaking, using thermal cameras, acoustic sensing and pressure testing, and hands over a documented technical report. Book from the order page or on WhatsApp at +966544027180.
- A licensed structural engineer: chronic damp with cracks, spalling concrete or exposed rusting rebar. See leak damage to concrete.
- Safety: damp near sockets and electrical panels means switching off the power before measuring.
Frequently asked questions
How do I make a moisture map of a wall correctly?
Divide the area into equal squares of 30 to 50 cm and mark them with masking tape. Take a reference reading in a dry spot on the same material. Then measure the middle of each square with the same mode and the same pressure. The shape the readings form matters more than any single reading.
What is a normal moisture meter reading for a wall?
There is no single value for every meter, because many give a relative scale that varies with the mode and the material. The better approach is to compare with a reference reading on the same material in a dry spot. Readings that are clearly above the reference and form a pattern are the ones that matter.
What is the difference between pin and pinless moisture meters?
A pin meter measures resistance between two pins inside the material, giving a reading at a precise point, leaving holes and reacting to salts. A pinless meter measures beneath its sensor pad to a limited depth without marking the surface, but it reacts to nearby metal and hand pressure. Both work for a map if you keep your measuring method consistent.
Why does my moisture meter read high on a dry wall?
Usually because of metal near the surface such as rebar, a copper pipe or a metal tile trim, salts built up in an old wall, or surface condensation near an air conditioner. Compare with a reference reading, move the measuring point slightly and use a thermal camera to confirm.
How do I find the source of damp from a moisture map?
Look for the peak and the gradient. A clear peak that falls away around it means a source nearby. A gradient rising towards one edge means the source is outside the grid in that direction. Even high readings along the bottom of a wall that fall with height point to damp from the ground or the floor.
Can the app read any moisture meter?
It reads the number on any clear digital display and notes the mode or scale if one is shown. A reading is accepted if the confidence is high enough and the value is between 0 and 999. Very small or reflective displays need the camera moved closer and light from the side.
How many squares can I record in one map?
The grid goes up to 6 rows and 8 columns (48 squares), and one session allows 60 readings including retakes, so the largest grid fits with some margin. You can also start with a wide grid and then repeat a smaller one around the highest point.
When should I repeat the moisture map after a leak repair?
A few days after the repair, depending on the wall thickness and ventilation. Use the same grid, the same mode and the same reference reading, and compare the two maps. Readings falling gradually towards the reference show the repair worked. Do not start waterproofing or painting while readings are still high.
This guide is educational. It explains estimation tools that help you understand a situation and decide what to do next; confirming a leak and pinpointing it always requires an on-site inspection with instruments. Structural questions are for a licensed engineer to decide.