Question 1

What is DPC injection?

Accepted Answer

DPC injection is a method of forming a damp-proof course inside existing masonry by injecting a chemical system that creates a water-repellent zone within the wall.

Question 2

How does chemical DPC injection stop rising damp?

Accepted Answer

The injected chemical bonds to masonry pore surfaces, making them hydrophobic. This interrupts capillary action and prevents upward moisture movement.

Question 3

Does the wall need to be dry before injection?

Accepted Answer

No. Silicone-based DPC systems react with moisture within masonry and do not require the wall to be dry before installation.

Question 4

How long does it take for a chemical DPC to work?

Accepted Answer

Barrier formation occurs after injection, but drying of the wall above the DPC occurs gradually and depends on moisture load, salts, ventilation, and finishes.

Question 5

Is DPC injection suitable for all wall types?

Accepted Answer

Most masonry walls are suitable, but wall thickness, construction type, porosity, and condition must be assessed to determine the correct method and dosage.

Question 6

Can DPC injection fail?

Accepted Answer

Failures are rarely due to the product itself. Most issues arise from incorrect drilling, insufficient saturation, unsuitable wall conditions, or follow-on works performed too early.

Question 7

How much product is typically required?

Accepted Answer

As a general guide, approximately 300 mL per treated brick is used, equivalent to about 156 litres per cubic metre of masonry, adjusted for substrate acceptance and wall condition.

Question 8

Does DPC injection stop salts?

Accepted Answer

DPC injection stops further moisture rise but does not remove existing salts. Salt-contaminated plaster or mortar should be removed where required to prevent ongoing damage.

Question 9

Can plastering or rendering be done immediately after injection?

Accepted Answer

Drying time should be allowed where possible. If walls are very wet and time is limited, breathable renders and finishes should be used to allow continued evaporation.

Question 10

Is DPC injection a permanent solution?

Accepted Answer

When correctly installed and matched to wall conditions, chemical DPC injection forms a durable internal barrier designed for long-term performance.

Topic	Explanation
Is Silonexx safe to use in occupied homes?	Yes. Silonexx is designed for use in existing residential and commercial buildings. Once injected, it reacts within the masonry and does not remain active in the indoor environment.
Does the product give off strong smells?	Silonexx has minimal odour. Any light carrier scent present during installation dissipates naturally over a short period as the product settles within the wall.
Are there vapours released after installation?	No ongoing vapours are produced once injection is complete. The formulation is designed to integrate within the masonry rather than remain airborne or surface-active.
Is the injection fluid corrosive?	No. Silonexx is non-corrosive to masonry, mortar, and common building materials when installed correctly. It does not attack bricks, steel ties, or embedded elements.
Does the product remain inside the wall long-term?	The active silicone chemically bonds to the internal pore surfaces of the masonry. The carrier component is temporary and does not remain as a liquid within the wall.
Is Silonexx environmentally responsible?	Silonexx is designed to work within the structure of the wall rather than leach into the surrounding environment. Once bonded, the active components are fixed within the masonry.
Does chemical DPC injection trap moisture in the wall?	No. The treated zone remains vapour permeable. Liquid water movement is interrupted, while natural evaporation and drying can still occur.
Is protective equipment required during installation?	Standard trade PPE is sufficient during installation. No special containment or evacuation measures are required for normal residential applications.
Why do some products use a carrier component?	The carrier allows the active silicone to move deeply into the masonry before bonding. This ensures effective internal treatment rather than surface-level performance.
Is chemical DPC injection widely used?	Yes. Chemical DPC injection is a long-established method used internationally for rising damp treatment in residential, commercial, and heritage buildings.

FAQs | DPC Injection & Silonexx

Frequently Asked Questions