Humidity Control Materials in Building Science

Humidity control materials are specialised substances incorporated into building envelopes and interior finishes to moderate indoor relative humidity through reversible moisture sorption. By adsorbing excess water vapour when ambient humidity rises and releasing it when humidity falls, these materials reduce peak loads on mechanical systems, enhance occupant comfort and mitigate risks of mould growth and structural deterioration. Common classes include natural minerals (clays, diatomite), engineered porous silicas and zeolites, polymer–clay composites and hybrid coatings derived from industrial by-products. Key performance metrics encompass sorption capacity, adsorption–desorption rate, moisture buffer value and long-term cycling stability. Advances in microstructure tailoring, surface functionalisation and composite engineering have improved sorption kinetics, mechanical integrity and environmental impact, enabling passive or low-energy solutions across diverse climates and applications—from residential walls and ceilings to museum storage rooms and archival environments.

Research from Nature Portfolio

Recent studies have employed fractal and image-processing techniques to elucidate the multiscale pore architecture of coal-series diatomite. By analysing gas adsorption isotherms and three-dimensional reconstructions, researchers quantified mesopore and macropore distributions and calculated fractal dimensions, revealing that fine fractions exhibit a more complex network of mesopores while coarser fractions contain interconnected macropores. These insights enable precise tuning of pore size distributions to optimise moisture uptake capacity and diffusion pathways, informing the design of next-generation hygroscopic coatings and panels with enhanced sorption kinetics and stability.

Humidity Control Materials in Building Science publication trend

The graph below shows the total number of articles in humidity control materials in building science across all publications each year (not limited to Nature Index journals).

Technical terms

Hygroscopic material: A substance that sorbs water vapour from the atmosphere through physical adsorption or chemical absorption.

Moisture buffer value (MBV): A quantitative index expressing the amount of water a material adsorbs and desorbs per unit area per humidity change cycle.

Mesopore: A pore with diameter between 2 and 50 nm, critical for achieving high sorption capacity and moderate diffusion rates.

Macropore: A pore larger than 50 nm in diameter, facilitating rapid vapour transport and kinetics.

Adsorption–desorption kinetics: The rate processes governing moisture uptake and release, influenced by pore structure, surface chemistry and environmental conditions.

References

1. Self-similarity study based on the particle sizes of coal-series diatomite. Scientific Reports (2024).
2. A simple method to valorize silica sludges into sustainable coatings for indoor humidity buffering. Sustainable Environment Research (2022).
3. Study on Preparation and Humidity-Control Capabilities of Vermiculite/Poly(sodium Acrylate-acrylamide) Humidity Controlling Composite. Materials (2024).