How do the above-mentioned substances affect a natural lime plaster?

Construction materials have a certain resistance to (water) vapour diffusion. The higher the diffusion resistance coefficient the less water vapour a construction material can absorb and the less vapour permeable it is. If cement or synthetic binders are added to a natural lime plaster, for example, this vapour diffusion resistance increases. Moisture from the air in the room cannot penetrate and collects on the surface. This promotes the formation of mould. Our pure and highly vapour permeable natural lime plaster absorbs the moisture from the indoor air and thus prevents condensation.