Chemical Injection Damp Proof Course (DPC)

There is an extensive and profitable industry built on the misdiagnosis of damp issues. Many people are familiar with the term “Rising Damp.” However, you may be surprised to learn that it is extremely rare for moisture to rise from the ground independently.

Most properties are constructed with a Damp Proof Course (DPC) designed to prevent moisture from rising beyond a certain level. Historically, materials such as slate were used for DPCs, which have proven effective for thousands of years. Water cannot penetrate slate, nor can it penetrate the later materials used for DPCs.

So, why would you need a new chemical injection DPC? The reality is that it is highly unlikely you do. Often, damp issues are incorrectly diagnosed, likely to promote a company’s products. At Alpine Damp, we conduct hundreds of independent damp surveys each year, and we NEVER recommend injecting a new chemical damp proof course.

Elaine Blackett-Ord, chair of the Register of Architects Accredited in Building Conservation, has also criticised the notion of rising damp, emphasising its rarity. She noted that this self-perpetuating industry is believed to be worth over £200 million annually. ”

Vertical Damp Proof Membranes (Damp Proof Membrane)

Many damp-proofing companies typically inject a new DPC and then remove the plaster from the lower section of the internal wall up to a height of 1 meter. After this, the wall is coated with a non-breathable waterproof membrane, followed by a non-breathable gypsum-type plaster.

The intention behind this procedure is to hide the damp issue, leading customers to believe that the problem has been resolved. In reality, all that has been done is to block the moisture in the wall’s lower section, which does not solve the underlying issue. Trapped moisture can accelerate deterioration of the pointing and brickwork, eventually requiring significant repairs.

All properties with solid walls need to “breathe” both internally and externally. Therefore, covering the wall with a non-breathable vertical damp proof membrane is harmful to the property.

At Alpine Surveys, we do not recommend installing a vertical DPM, except in certain circumstances, such as in basements where a retaining wall needs protection. However, this should be a last resort after all moisture extraction techniques have been exhausted. Alpine Damp conducts completely independent surveys and has no connections with or ties to any remedial companies. This ensures that you receive an unbiased evaluation to determine the true cause of the damp issue, which often involves relatively inexpensive repairs that effectively resolve the problem.

Jeff Howell, a qualified bricklayer and author of “The Rising Damp Myth” (2008), has stated that laboratory tests confirm that the concept of rising damp is a myth. He noted, “If you build a brick pillar and stand it in a tray of water, the bricks in the water will get wet, but the water doesn’t rise by capillary action.” He also mentioned, “Cement-based and most lime mortars will not allow water to penetrate.”