Amongst all moisture-related problems rising damp is probably one of the more controversial topics in the UK. As mentioned on a different page, the concept that over time vapour movement alone, without liquid moisture, can cause rising damp - is a new view on rising damp which was missing for decades, creating an industry-wide confusion on this subject.
This in the building industry resulted in conflicting viewpoints on the subject (e.g. rising damp doesn’t exist, it's extremely rare, it can't be found etc.) making this topic even more difficult to comprehend, especially for non-professionals.
The good news is, the situation is much simpler. Although rising damp is a complex phenomenon involving vapours, liquids, salts etc, in the scientific community there is a uniform global consensus and view on rising damp (throughout Europe and worldwide) that it is a common occurrence, it is a problem, and it causes significant damages to old buildings. Other individual viewpoints thinking this otherwise are also explored in detail here.
On the following pages we would like to explore in depth both viewpoints and thus hopefully bring more clarity into this subject, so you can decide for yourself whether rising damp should be considered or ignored.
As most scientific research these days is carried out by Universities and independent research establishments, their view on rising damp or the overall viewpoint of the "academia" can be considered highly relevant and authoritative. Let’s see what is the view of universities on rising damp.
By exploring the scientific literature one can find hundreds peer reviewed university research papers from highly-trusted sources describing many aspects of rising damp in detail.
The world's largest peer-reviewed research platform, Elsevier ScienceDirect, at the time of this writing listed 579 peer-reviewed research papers about rising damp. Another highly regarded research portal, Web of Science, listed 236 research articles on rising damp.
Peer reviewed papers, which have been checked by other researchers or experts of a field for technical accuracy, are considered a highly trusted source of information.
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Here is a selection of research papers highlighting researchers' view on rising damp, with links to the original source publications. The abstract (short summary) of these papers is freely available. Full-text versions in most cases require a subscription, however some full papers are freely available under the open science framework.
Here are some professional statements made by researchers about rising damp.
Rising damp is one of the main problems affecting historic masonry buildings, as it leads to severe consequences, in terms of both bad indoor conditions (high air relative humidity) and materials deterioration. The phenomenon of rising damp is very common in ancient buildings.
State-of-the-art on methods for reducing rising damp in masonry - Journal of Cultural Heritage, 2018Rising damp is an important cause of wetness in buildings. It is a cause of decay and deterioration in standing stones, monuments and at archaeological sites. Rising damp is a complicated process.
Rising damp: capillary rise dynamics in walls: - The Royal Society Publishing, London, 2007Rising damp is a recurrent hazard to ancient buildings in Europe and its relevance is expected to increase in the future, due to climate changes.
Effectiveness of methods against rising damp in buildings; Results from the EMERISDA project - Journal of Cultural Heritage, 2018Fresh or sea water rising damp in historical buildings is a well-known problem. Venice is the emblematic case of a historical maritime city affected by rising damp.
Rising damp in historical buildings: A Venetian perspective - Building and Environment, 2018Serious rising damp can lead to a building becoming inhospitable due to mould growth, paint blistering, plaster crumbling and wallpaper separation. It is a vexatious and persistent problem requiring a great deal of effort and financial resources in addressing its manifestation, typically with varying degrees of success.
Evaluation of mortar samples obtained from UK houses treated for rising damp - Construction and Building Materials, 2011
In old buildings, rising damp in walls that are in direct contact with the ground leads to the migration of soluble salts that are responsible for many of the pathologies observed.
Some professional textbooks explain the view on rising damp of some top-level professionals. Here is this 270-page Austrian technical reference book "Building Dehydration - From Basics to Practical Applications" published in 2017, which discusses in great detail many aspects of wetting and drying as well as the basics of moisture movement and building Physics.
The book also details the development of rising damp as a result of various vapour and liquid transport phenomena. The book makes a clear distinction between rising damp and condensation, which are two different phenomena.
The stages of dehydration and various mechanisms that contribute to the dehydration of the building fabric are also presented in a logical and structured way.
Lab experiments give us a practical view on rising damp. Rising damp can be recreated in an artificial lab environment very easily. This is being done regularly in many research labs as part of the ongoing research. Some of the research papers listed above contain actual photos of rising-damp related lab experiments such as the one here.
As part of our in-house research program we have also recreated rising damp in our own labs. In our observation, in order to get decent results, it is important to use porous "old-style" bricks. Harder, modern or less-porous bricks have much slower moisture uptake, which might explain some past failures to recreate rising damp successfully within the experimental time-frame.
By using "old-style" but otherwise new porous bricks purchased from a brickyard, we managed to get water rise to about 1 metre high within 4 days. Here are our figures:
All this occurred in a condensation-free, uniformly-heated, protected environment.
We captured the whole process on a time-lapse camera - take a look, it looks pretty cool.
Some factual calculation can give us a real-life view on rising damp, on some of its numeric aspects. The amount of water that old walls can accumulate from the ground can be truly staggering.
One of the scientific papers listed above, published by the Royal Society of London1Hall Christopher & Hoff William D (2007) Rising damp: capillary rise dynamics in walls, Proc. R. Soc. A.4631871–1884 https://doi.org/10.1098/rspa.2007.1855 provided the formulas to calculate some of the key parameters of rising damp. These calculations included:
Being a research paper published in the UK, all figures were given for UK climate conditions, and the numbers are really interesting. Here are some of the key figures for a somewhat "average" 500 mm thick wall:
I have verified these calculations in Excel, running a few "typical" scenarios for comparison purposes, to better understand how rising damp behaves at different wall thicknesses. Here are the calculations:
What these figures tell us, what can we conclude:
The rising damp phenomenon has been consistently documents for almost 200 years. Written historical records are available in forms of various period publications and books.
The amount of independent, third-party information about the existence of rising damp is really staggering, the phenomenon being well-documented since the 1840s. Many architectural and professional books have described the problem, also advising about various solutions on how to overcome it.
Click on any of the titles below to expand more content.
The first known written historical reference about rising damp goes back to ancient Rome. The Romans, being excellent engineers, that have built some masterpieces that lasted over 2000 years. Historic records show that they not only were aware of rising damp, but they have also devised efficient solutions to combat it.
Roman architect and engineer Vitruvius in his famous Ten Books on Architecture has described the type of plaster mix that should be applied on walls near ground level subject to ground moisture:
The Builder was a journal of architecture published between 1843 and 1966. Issues from year 2 (1844) mention dampness rising from the ground due to capillary attraction. As a solution, to prevent the ascent of moisture up the walls, it recommends the use of slate inside the walls.
This professional textbook from 1851 is a practical manual written for architectural students, engineers, contractors and builders.
Dedicating a whole chapter to dampness, including to the prevention of rising damp, stressing the importance of separating the foundations from the rest of the wall with a damp proof course, to stop the upward migration of dampness.
French architects, independently, came to the same conclusion. Even if the footing of a building is always underwater (e.g. in a lake), using less than half an inch thick asphalt DPC keeps the walls completely dry.
This paper read on 12 Jan 1863 at the General Meeting of the RIBA, discusses the sanitary aspects of rising damp in old buildings, and various damp proof course options as a natural remedy to the problem - about 20 years ahead of global UK sanitary reforms.
A new damp proof course is also presented to the attending architects - a layer of perforated bricks, laid as a row of ordinary bricks, to prevent the rise of moisture, while also improving underfloor ventilation.
Some of the architects' comments on this damp proof course technology included:
A report of the British Medical Journal dating 20 Dec 1873 discusses various sanitary aspects of rising dampness in houses, hospitals and public institutions.
Various damp proof course technologies used by architects are mentioned in the paper, including double course slates, Welsh slate bedded in cement, sheets of lead, hot asphalt DPCs, glazed bricks and vitrified stone-ware tiles.
The paper also advises the retrofitting of a damp proof course into old buildings, which turned uninhabitable buildings into perfectly healthy ones.
This 3-volume publication from 1876 was the official syllabus of a three-part advanced building construction course. A whole chapter is dedicated to the problem of dampness and how to efficiently overcome it, including rising damp, penetrating damp and falling damp from the roof or gutters.
Various damp proof course technologies are also discussed, making reference to the fact that slate DPCs embedded in cement are liable to crack and thus fail.
Glazed pottery slab damp proof course built into the wall:
Lastly, according to an official report from the 1867 Paris Exhibition, some interesting technical facts from the book on how much water saturated brickwork can hold:
Realizing the effect of damp walls onto the health and well-being of inhabitants, between the 1870s - 1890s a number of health bills have been passed throughout UK, all of them recommending damp proof courses as a means to combat capillary rising damp.
Solution to the problem is a vitrified (glass-like) layer of bricks or two layers of slate.
The book also provides technical advice with drawings, presenting the incorrect way of laying a slate damp proof course, with gaps left between them.
Clause 96 of the The London Public Health Act from 1891 stipulates the use of damp proof courses for underground rooms:
Old books from the Victorian period have also documented that problems caused by rising damp, which were well-known in Victorian England, describing damages done to old 16th - 17th century cottages and country houses.
All these books are freely available from the Internet Archives as part of Google's old books digitization project. They can be freely viewed and downloaded as PDFs by anyone.
Click on the titles below to expand the references.
This American book published in 1851 discusses important aspects of house building in the United States: design, materials used, finishing, heating & ventilation etc. The problems of dampness is also addressed, highlighting the importance of damp courses (or the use of hydraulic mortars) to prevent dampness from rising.Â
The book also discusses in details most building materials used in the 19th century, highlighting that stone houses built without a damp proof course are more or less damp...
... and common lime mortar will not stop rising damp from the ground.
This book published in 1870 presents 45 private residences of its time, focusing on practical aspects of house building, including: how to properly build walls, construct floors, roofing, ventilation, drainage, what materials to use etc.
The problem of dampness is also discussed in detail, with practical advice on how to prevent it, overcome it and build a dry, comfortable home. Rising damp must always be addressed by laying a damp course under every wall, whether internal or external.
This book published in 1905, presents examples of typical domestic buildings, including some of the most noteworthy houses from Victorian England. The book highlights damages caused by rising damp in many old 17th century cottages - making some rooms almost unusable for living.
The reason why the ground floor rooms of many old cottages were wet and unhealthy, especially during winter time, was lack of damp proof courses, an unknown technology at the time when these cottages were built.
This book published in 1909 highlights the damp, disused condition of some rooms in old cottages due to lack of damp courses.
This book published in 1914, dealing with the restoration of old houses - weather cottage, farm house or small manor house - presents is detail the history, problems and restoration challenges of 40 old buildings stretching back 5 centuries.
Problems caused by rising damp are repeatedly highlighted, linking the problem and associated damages to lack of damp proof courses, unknown when these buildings were originally built. Several such examples are presented, and poor workmanship is also mentioned.
The paper also advises the retrofitting of a damp proof course into old buildings, which turned uninhabitable buildings into perfectly healthy ones.
Some repairs followed the principles laid down by the Society for the Protection of Ancient Buildings, the SPAB, already in existence since 1877. The book praised the SPAB's rigorous work and conservative approach in retaining as much old building fabric as possible. At one building the repair works also included the insertion of a solid damp proof course while undertaking some foundation works.
This book published in 1915, written by the Medical Officer of Somerset County, discusses important aspects of rural housing, including: the housing shortage, housing conditions, health and sanitary problems etc. The effect of various types of dampness are discussed in detail, based on the findings of professional surveyors.
Rising Damp is listed as a major problem that can be remedied with difficulty. The solution is fitting a solid DPC while other works are being undertaken. Failing to do so, the lack of a damp proof course, often makes old buildings uninhabitable, also resulting in their long-term decay.
Here are some practical solutions related to this topic:
