Sydney Based + National Delivery
Sydney Based + National Delivery
This page explains the chemical and physical mechanisms by which silicone-based DPC injection fluids operate within masonry. It focuses on what occurs inside the pore structure after injection and why correct distribution and saturation are critical.
It is intended as a technical reference for contractors and specifiers, not a marketing overview.
Masonry materials such as brick, stone, and mortar contain a network of capillaries and pores. Rising damp occurs when water migrates upward through this network due to capillary action.
Chemical DPC injection does not block these pores. Instead, it modifies how water interacts with the pore surfaces.
Silicone-based DPC systems typically contain alkoxysilanes and siloxanes.
Once injected into masonry, these compounds undergo two key reactions:
These reactions occur naturally within the wall after injection.
Masonry minerals contain surface hydroxyl (–OH) groups.
During condensation:
Silane molecules chemically bond to these hydroxyl groups
Covalent bonds form between the silicone compound and the masonry surface
A durable, chemically anchored treatment is created within the pore walls
This is a chemical bond, not a surface coating.
Once bonded:
The pore walls become hydrophobic
The pore structure remains open to vapour movement
Liquid water is no longer able to wet the pore surfaces
The treated zone functions as an internal damp-proof course.
The injected silicone system does not convert water or block moisture mechanically.
Instead, it alters water behaviour by:
Water vapour can still pass through the wall.
When correctly dosed and distributed:
Continuity depends on correct drilling, spacing, and saturation.
Chemical bonding occurs only where the fluid reaches.
Insufficient saturation leads to:
Correct volume and distribution are critical.
Hygroscopic salts do not prevent chemical bonding, but they:
Salt-affected plaster and mortar should be removed where required to avoid misleading post-treatment symptoms.
Silicone-based DPC injection works by chemically modifying the internal pore surfaces of masonry, creating a vapour-permeable, water-repellent zone that interrupts capillary moisture rise when correctly installed.