Saponification
The chemical breakdown of a coating by alkali, in which the binder reacts with alkaline salts in fresh cementitious substrates and loses cohesion.
On an actual building
It is why an alkali-resistant primer is essential on new render. Without one, the topcoat chalks, softens and lifts, and the failure is usually blamed on the paint rather than the missing primer.
What we most often have to correct
That paint failure on new plaster means poor-quality paint. It usually means the substrate was alkaline and unprimed.
Where this comes up in our work
Terms that come up alongside this one
- Alkali Resistant Primer
A primer formulated to resist the high alkalinity of fresh cement render and provide a stable base for a topcoat..
- Efflorescence
White crystalline deposits left on a surface when water moving through masonry or concrete evaporates and leaves dissolved salts behind..
- Acrylic Coating
A water-based coating with good UV stability and colour retention, widely used as an exterior decorative and protective finish..
Saponification — questions we get asked
What does saponification mean in waterproofing?
The chemical breakdown of a coating by alkali, in which the binder reacts with alkaline salts in fresh cementitious substrates and loses cohesion.
Why does saponification matter on a real project?
It is why an alkali-resistant primer is essential on new render. Without one, the topcoat chalks, softens and lifts, and the failure is usually blamed on the paint rather than the missing primer.
What do people commonly get wrong about saponification?
That paint failure on new plaster means poor-quality paint. It usually means the substrate was alkaline and unprimed.
Have a building showing this?
If a term on this page describes something you are looking at, a site inspection will tell you how far it has gone and what it needs. It costs nothing.
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