Rising Damp refers to water that rises from the ground through a building’s masonry walls due to capillary rise dynamics. It can also result in wood rot in the abutting floor, damp walls, and masonry deterioration—more information from The Royal Society. This is the reason building regulations require a Damp Proof Course to be installed.

In the beginning

The effort to control rising damp began in the early 1800s, prompted by health concerns. It started with the installation of a poured bitumen damp proof course (DPC) set 6 inches below the floor level. This evolved into by-laws that mandated the external ground be maintained at least 6 inches below the DPC line. This measure was aimed at protecting timber floors and preventing issues such as dry rot. The use of bitumen for this purpose was prompted by a significant discovery of bitumen near the city of Huy, Belgium, at the beginning of the 1800s.

Some materials:

• Slate course in the wall.
• Taylor’s DPC, which is an elongation in vitrified (fire clay) of the ordinary air brick.
• Solid engineering bricks laid in a course to block moisture.
• Dense mortar using 3:1 sand with Portland or Traditional cement.
• An Impermeable stone like whinstone (mortar is the weak point and pathway).
• Thin Lead role on brick.
• Bitumen roll from 1920 onward.

In 1891, the damp proof course material was defined as a material impervious to moisture (changed after 1914). It was approved by the District Surveyor and positioned at a level not less than 6 inches below the level of the lowest floor of every external wall.

Still, there were issues with the availability of suitable damp-proof course material in some areas. Additionally, there was the Architects’ resistance to using it in some locations due to the building’s visual aesthetics. Developers and builders also resisted change due to the cost of the work.

Conclusion:

• Rising Damp is less likely to be found in buildings constructed in the 19th century. This is because Model by-laws were in place as early as 1845 and evolved in legislation over the 19^th century. In the 20^th century, rising damp is unlikely in any dwelling built correctly. The changes culminated with CP102:1973 A Code of Practice for the Protection of Buildings against Water from the Ground and its subsequent upgrades.
• As you can see, over the past 200 years, significant efforts have been made to combat the persistent problem of rising damp in buildings. As a result of these advancements and innovations, modern structures are far less susceptible to this age-old problem. The transformation has led to drier, healthier living environments, showcasing the remarkable progress made in building technology and design.
• Some of the Rising damp controversy stems from the home purchase market. In the 1960s, electrical moisture meters became more widely available. This, combined with the availability of a chemical treatment for rising damp. This new chemical repair helped facilitate the sale of run-down dwellings. This work made mortgage lenders feel more at ease.

Notes:

• Rising damp, according to some people, is a myth—like the belief that the world is flat. However, neither side has provided conclusive evidence to support their claims. Additionally, some designers and builders utilise eco chambers to justify shortcuts and inadequate damp-proofing methods. As Plato noted, the outcomes of such actions are often rooted in human nature: “All wrongdoing is due to ignorance; therefore, it is involuntary.” This perspective encapsulates the historic challenges present in the construction industry.
• In the 19th century, “the dry rot” was only a visual description of what happened to timber.
• A Model by-law is a regulation that promotes the best practice.
• Some References: Roger Henley Harper. Evolution of English Building Regulations 1840-1914. Property Care Association.