Salt Crystallisation
Damage caused when salts dissolved in moisture crystallise within the pores of masonry or plaster, exerting pressure as they grow.
On an actual building
It breaks material apart from within, which is why repainting over efflorescence fails every season. On coastal buildings the salt supply is effectively continuous.
What we most often have to correct
That the visible white deposit is the damage. The visible salts are the harmless ones that reached the surface; the damaging crystallisation happens inside the material.
Terms that come up alongside this one
- Efflorescence
White crystalline deposits left on a surface when water moving through masonry or concrete evaporates and leaves dissolved salts behind..
- Chloride Attack
Corrosion of reinforcement driven by chloride ions penetrating the concrete, typically from sea air, sea spray or brackish groundwater.
- Breathability (Vapour Permeability)
The ability of a material to let water vapour pass through it while still resisting liquid water..
More deterioration terms
Salt Crystallisation — questions we get asked
What does salt crystallisation mean in waterproofing?
Damage caused when salts dissolved in moisture crystallise within the pores of masonry or plaster, exerting pressure as they grow.
Why does salt crystallisation matter on a real project?
It breaks material apart from within, which is why repainting over efflorescence fails every season. On coastal buildings the salt supply is effectively continuous.
What do people commonly get wrong about salt crystallisation?
That the visible white deposit is the damage. The visible salts are the harmless ones that reached the surface; the damaging crystallisation happens inside the material.
Have a building showing this?
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