Technician applying damp proof injection cream to interior wall in house

What is a Damp Proof Injection and How Does It Work?

What is a Damp Proof Injection?

A damp proof injection is a remedial damp proof course (DPC) used to damp proof buildings where the original damp course is damaged or deteriorated over time.

If the damp proof injection cream is installed correctly, not only will it ensure the property is treated from rising damp, but it will also provide a reliable long-term solution for it not to return again in the future.

How Does a Damp Proof Injection Work?

Using a damp proof injection cream is probably the most efficient and economical method of treating rising damp within your property.

  • Holes are drilled into the mortar joints
  • The cream is then injected into the holes.
  • The cream creates a water repellent barrier that provides full protection against rising damp.

It is important to note that damp proof injection is also useful if the wall is saturated with water.

Why Do You Need Damp Proof Injection?

Rising damp on internal walls

Rising damp stain on the wall due to no damp proof injection in place

The most important reason for using a damp proof course injection at your property is to provide a barrier to stop the moisture from rising. Rising damp can also occur if the ground level outside of the property is higher than the damp proof course, this process is called bridging.

One of the problems associated with rising damp is that because salts are concentrated and water absorbed from the air means that it can cause contaminated finishes to appear damp. When decorative finishes are applied then this would deteriorate further over time.

Another issue is that if rising damp affects the timbers of the building then one of the outcomes could be dry rot. Dry rot can cause severe structural problems to the building’s integrity if not discovered and treated quickly enough.

Damp Proof Cream Injection Carried Out Correctly

Injecting a damp proof course into a wall

Injecting a damp proof course into a wall

Preparations will be made both internally and externally before the damp proof cream can be injected into the wall. The first step is to remove any skirting boards, connecting radiators or any other fixed fixtures to provide access for the technician to start the process.

If rising damp is causing problems at the property, then any damaged or contaminated salt plaster will need to be removed. The plaster will usually be then be removed in a process known as ‘hacking off’ to a height of no less than a metre.

There are some unusual cases where the moisture is higher than a metre which means the technician will remove the plaster 300mm above the highest point where the damp or hydroscopic salts can be seen.

Once all the measures have been put in place then the damp proofing cream can be injected into the hole. The technician will first drill holes of approximately 12mm depth horizontally into the wall mortar joint.

If this procedure is not possible then flanking works will need to be implemented to ensure there is no bridging of the damp course.

The damp proofing cream will then be injected into the boreholes using a cartridge gun. The silane will then start to work by creating a barrier against the rise of moisture from the ground level.

After the Damp Proof Injection Cream has Been Installed

Once the damp proof cream has been injected into the walls of the building then re-plastering will then need to be carried out on the internal walls of the building. This process should be delayed for as long as possible to ensure there is enough time for the walls to dry out.

All replastering materials that are used should ensure that any remaining salts in the brickwork should not affect any new plaster.

How NOT To Inject A Damp Proof Cream?

We would always recommend you contact a damp specialist to carry out damp proofing works at your property. The main reason for this is that especially when injecting a damp proof course there are a number of errors that can occur that could easily be avoided.

At Timberwise, we have seen past work from local tradesmen, without the right damp proofing training, that have made common mistakes that have led to property owners having worse damp problems than they originally had before.

This usually means that our Timberwise surveyors and technicians have to fix the damp essentially from scratch, which obviously adds to the cost of rectifying the problem.

The common types of mistakes that can occur from misdiagnosis of the damp problem and injecting a damp proof cream incorrectly are:

  • Not identifying that there is a DPC in place and Injecting another DPC when there is already one functioning damp proof course in place.
  • Drilling directly into the stone or brick instead of drilling into the mortar line
  • Applying the damp proof cream into pre-existing holes where the damp proof course has failed.
  • Injecting a damp proof course when there is a bridging of cavity walls. This will over time fill up with debris and can bridge the damp course, the moisture will pass through and cause damage.
  • The injection takes place into an already poor quality or damaged mortar joint. Before any damp treatment can take place, this will need to be fixed for the DPC to be effective.

Contact A Damp Proofing Injection Expert

We hope this gives you a better understanding of how a damp proof injection works and why it is necessary to have a DPC installed if your property is suffering from rising damp.

If you would like to speak to an expert for more information or would like an inspection for damp proofing works to be carried out, then simply contact us online by clicking the link down below.