Porous, mineral building materials are traversed by a network of pores and capillaries of various types, sizes and forms, which are essential for water transport. Depending on the moisture content in the building material, water transport basically takes place in two different ways: diffusion and water current.

In case of diffusion, water vapour can flow through the entire pore space (1).

With increasing moisture content, a water film forms at the surface of larger pore spaces, smaller pore bottlenecks are already completely filled with water (2).

When the building material is supersaturated, there is so much water in the enhanced pore spaces that it can only be transported in form of current (3).

This liquid water transport phase is far more efficient than diffusion.

In consequence we can stipulate the following regarding the suitability of infrared heating panels for wall drying:

1. Drying by means of infrared heating panels is only reasonable with building materials with a high porosity and well-formed capillary systems, e.g. bricks and some natural stones.
2. In case of greatly compacted wall building material with closed structures or small capillaries (concrete), the application of infrared heating panels has no drying effect, because water transport is predominantly effected by diffusion.
3. An efficient drying performance can only be achieved in the liquid phase. The moisture follows the heat flow only during this phase.
4. When the water current breaks off with an increasing degree of drying, transport is progressively effected by means of diffusion. From this moment the application of infrared heating panels is of no importance to the drying progress!

Conclusion: For as long as liquid water transport in soaked building materials is effected by means of water current, infrared heating panels can help to speed up drying.

Infrared heating panels, however, cannot fully replace dehumidifiers to achieve an equilibrium moisture content in the building material!