At Highpoint Solutions we focus on innovative technologies that let us create higher value, more sustainable, more efficient and safer work environments. Microwave reflection based moisture mapping is one of them, and it changed how we investigate a building leak.
The problem with measuring moisture at the surface
Most moisture instruments read the surface, or just under it.
A resistance meter measures conductivity between two pins, which is affected as much by salts in the material as by water. A capacitance meter reads a shallow layer and is sensitive to density and surface finish. An infrared camera does not measure moisture at all — it measures surface temperature, and infers moisture from evaporative cooling.
All three are useful. None of them tells you how much water is sitting 100 mm inside a slab, or whether the wet zone is in the screed or the substrate beneath it. On a building leak, that is usually the question that decides the scope of the repair.
What the microwave method measures
Water has a much stronger dielectric response than the materials it gets into. Concrete, render, screed, brick and insulation are all comparatively transparent to a microwave field; water is not.
A sensing head emits a low-power field into the element and measures how that field comes back. The change is driven overwhelmingly by the water present, so the reading tracks moisture content largely independently of the material's other mechanical, chemical and physical properties — which is precisely where conventional methods struggle.
Two consequences matter in the field:
- It reads volume, not surface. The measurement represents moisture through an interaction volume inside the element rather than a film on its face.
- Depth is chosen by the head. Different sensing heads interrogate different depths, so a wall or slab can be mapped in layers — surface, intermediate, deep — and the moisture profile through the element read off rather than guessed.
That layering is what separates residual moisture from an active leak. A drying slab is wet at the surface and dry beneath. A leaking one is the other way round.
What it is good for
Practically, the method is:
- Non-destructive. Nothing is drilled, cut or opened up.
- Fast. Real-time measurement, so a grid can be walked rather than sampled.
- Optimised for volume of readings. Hundreds of measurement points across an area is normal, which is what makes a map rather than a handful of spot readings.
- Deep. Penetration well beyond what surface instruments reach.
- Unaffected by salinity, depending on the head selected — the failure mode that makes resistance meters unreliable in coastal and rising-damp work.
Because the equipment is portable, we can also deploy it via rope access, which puts it on façades, balconies, plant rooms and elevated pipework that would otherwise need scaffold before anyone could take a reading.
Applications
- Condensation moisture
- Residual moisture
- Upsoaring moisture — hygroscopic moisture by salinisation
- Moisture damage by thermal bridges
- Leakage through defective wall seams
- Water leakage in floor construction
- Moisture under process pipe insulation (Armaflex, Arma Cryogel, Pyrogel, GRE)
That last one is worth drawing out. Wet insulation on process pipework is the precursor to corrosion under insulation, and it is invisible from outside the cladding. Finding it before it becomes wall loss is far cheaper than finding it afterwards.
Why it runs alongside thermography, not instead of it
The two methods answer different questions, and neither is sufficient alone.
Thermography covers area fast. An infrared camera scans an entire elevation or floor in minutes and shows where the thermal pattern is anomalous — but a cool patch can be evaporation, a draught, a shadow, a different material or a thermal bridge. It tells you where to look, not what is there.
Microwave moisture mapping is slower and local, but it answers the question thermography cannot: is there actually water in this element, how much, and at what depth.
Used together, the camera narrows the search and the moisture map confirms it and defines the extent. That combination is what lets us write a report saying which area is wet, how deep, and how far it runs — rather than a report that says a patch looked cold.
What it does not do
Being straight about the limits:
- It measures moisture, not the leak. It defines the wet zone; tracing that back to a source still takes method — pressure testing, acoustic location, tracer gas or thermography, depending on the situation.
- Readings are comparative. The useful output is a map of relative moisture across an area with a dry reference, not a laboratory moisture percentage.
- Heavily reinforced concrete and some metallic finishes interfere with the field, and those limitations belong in the report rather than being quietly ignored.
Where this sits in a job
For a building water leak we would typically run a thermographic scan to find the anomalies, map the suspect areas with microwave moisture measurement to establish depth and extent, then use whatever location method the situation calls for to find the source.
The output is a defined wet area with a moisture profile through the element — which is what a builder, a waterproofer or an insurer can actually act on.
Full detail of the service is on the building water leak detection page.