Can I inject a damp proof course?

Damp Proof Treatment Using Injections



If your property is suffering from rising damp, then any salt contaminated plaster will need removed before injecting a damp proof course. Plaster is usually removed to a height of no less than one metre to remove the salt affected plaster prior to injecting the chemical DPC.

Where do you inject chemical DPC?





To form a vertical DPC, inject the chemical into holes running in a zigzag pattern that follows the mortar line up the wall to a height of at least 1 metre. The cream can be injected from either side of the wall, though for cavity walled brickwork, we recommend injection from both sides.

How long does a chemical DPC last?

20-25 years

Typically, a physical damp proof course lasts for 20-25 years and can fail due to it not being fitted properly or deterioration. If a damp proofing course has failed then this could potentially lead to rising damp. Rising damp is the movement of moisture through the walls and floors by capillary action.

Which chemical is used for DPC?

a) Bitumen Mastic (Mastic Asphalt)

Can you inject DPC from inside?





In short, yes you can inject from the inside. In fact we normally inject from the inside as when the skirtings put back the injection holes are not visible.

Can you inject DPC into brick?

DPC injection is designed to seep into the brickwork to prevent moisture rising up through the bricks by capillary action and causing rising damp. The active component, silane, lines the capillaries before drying. This creates the water repellent barrier.

Should damp proof holes be filled?

By far the quickest, most economical and effective method to treat rising damp is to use a high strength damp proofing cream. This cream is injected into holes drilled in the mortar joint.

How do you damp proof a wall below ground level?

Quote from the video:
Quote from Youtube video: We would then waterproof the bricks by tanking. Put back the plaster. And then once the plaster is dry we waterproof the plaster and put back the soil.

How do you treat rising damp injections?



The most common and effective way to treat rising damp is to install a remedial damp proof course by injecting a water repellent damp proof cream into the mortar bed joint of affected walls.

Which material is best for damp proof course?

Materials widely used for damp proofing include:

  • Flexible materials like butyl rubber, hot bitumen (asphalt), plastic sheets, bituminous felts, sheets of lead, copper, etc.
  • Semi-rigid materials like mastic asphalt.

What are the 3 types of DPC?

Types of Damp Proofing Course

  • Hot Bitumen. The hot bitumen type of damp proofing course is a flexible material that is placed on the mortar or the concrete bed. …
  • Bituminous Felts. The bituminous felt also flexible material. …
  • Metal Sheets. …
  • Mastic Asphalt. …
  • Stone. …
  • Mortar. …
  • Cement Concrete.



What is the difference between DPM and DPC?

DPC stands for damp proof course whilst DPM stands for damp proof membrane. A DPC is a material placed between courses of brickwork to stop the rise of water up the walls. The types of products used can include polythene materials, pitch polymer combinations or even materials such as slate.

Does DPC go on top of DPM?

The height at which the DPC is installed would normally be a minimum of 150mm above the external ground level. The DPM should then be folded up the inside wall and lap over onto the DPC thereby forming a continuous water barrier.

Do you need DPM and DPC?

Damp Proof Course (DPC) and Damp Proof Membranes (DPM)



DPC and DPM are most commonly applied at below floor level which restricts the movement of moisture through walls and floors. This safeguards concrete from gaining any moisture and helps prevent cracks.

How many layers does a damp proof membrane have?



It is recommended that a minimum of two coats are used, up to three coats depending on the moisture content of the slab.

Can you overlap damp proof membrane?

When joining two sheets a minimum overlap of 150mm should be provided between each of the sheets. For the best waterproof protection when making a join a double welted fold should be formed between the joining sheets. This should be formed by an overlap of 300mm from both sheets.

What is the thickest DPM?

1200 Gauge DPMs

1200 Gauge DPMs



The DPM thickness is the recommended 300μm and 1200 gauge – this means it effectively prevents moisture from passing from the ground into the property. This provides long term protection to the upper surface of the floor from damage. You should always consider a DPM before installing any flooring.

How long does a DPM last?



Most damp proof wall membranes are made from HDPE and have a high compressive strength and a long life expectancy (over 30 years). They are extremely flexible and have an elongation break of over 40% therefore they are able to deal with structural movement.

Can you put DPM on top of concrete?

DPM’s can be applied to either a suitable blinding layer under the slab or internally to the top of the slab. Consideration should be given to applying the DPM to the top of the slab, as the installation and moisture sensitive internal finishes are then protected from any residual moisture in the concrete.

How thick should DPC be?

40mm thickness

The DPC should be of 40mm thickness and should be of uniform thickness. It should not be provided at the locations of the door openings. The top level of DPC should match with the planned finished floor level.