How to Investigate Damp

Practical Site Inspection Skills and Remedial Options

Ralph Burkinshaw

• Publisher: Routledge
• Year: 2020
• ISBN:
  9781000204131
• Edition: 1
• Topic: Architecture
• Subtopic: Architecture General

The aim of this book is to take the reader by the hand and show them exactly how to carry out various inspection techniques to identify the causes of damp in buildings. This is achieved by taking them through a variety of investigation methods using real-life case studies illustrated by dozens of sketches, drawings and photographs – and considerable insight into how investigations can be conducted on site – and also including most importantly the Client's input and perspective on a damp issue.

Written in non-technical language by a leading expert and author on damp, the book begins by outlining the common types and phases of an investigation, the equipment required and the nature of potential remedial work. Case studies then cover condensation, penetrating damp, plumbing and roof leaks, below ground moisture and damp bridging – and some innovative remedies installed by the author himself. The final section contains step by step guidance on procedures such as using a humidity box, inspecting a cavity wall, using a damp meter and extracting and testing a plaster sample for salt content.

The book is full of hints and tips developed over a career spent investigating, diagnosing and remediating damp issues and is essential reading for surveyors looking to improve their skills and knowledge of this often complex defect. The book will also be very useful for homeowners trying to self-diagnose, and architects, engineers and other professionals who need to gain insight into common problem caused by moisture imbalance in buildings.

Chapter 1

Introductory matters

1.1 Why is a ‘dampness investigation’ necessary?

Most property surveyors would surely agree that the commonest property problem is damp damage caused by unwanted moisture. Problems usually arise when there is too much rather than too little moisture on or in a building material, element or component – or even in the air inside the habitable space. Second on the list might be structural failure of a building element or component part – and even this category of building failure may itself have been prompted by material degradation from unwanted moisture.

In spite of the fact that too much dampness is regularly the root cause of so many property defects, the investigating of dampness does not yet appear to be sufficiently recognised as a core skill area by the various professional property institutions.

The text ‘Diagnosing Damp’ [1] was published 17 years ago by RICS Books, with the follow-up text ‘Remedying Damp’ [2] adding to that knowledge bank six years later. ‘Diagnosing Damp’ explained how damp problems could be inspected and diagnosed using a variety of diagnostic techniques, ranging from basic use of a damp meter to more advanced methods such as salts and moisture content analysis of masonry or plaster samples, or data logging to monitor a condensation issue. ‘Remedying Damp’ introduced readers to a number of useful remedy approaches.

Surveyors could no longer ignore the limitations of brief inspections of damp issues. These texts ought to have prompted at the very least the development of professional guidance notes on the investigation of dampness issues. Furthermore, without the framework of an RICS Guidance Note, chartered surveyors investigating dampness as a core activity are a little out on a limb and left to create their own methodologies. This text expands on techniques introduced in the first two texts by showing exactly how equipment and tools are used on-site to further our investigations.

If a damp problem is merely flagged up rather than being fully investigated, there are a number of possible implications:

1. The cause (or causes) of the subject damp problem is not correctly identified.
2. The remedy devised may not solve the damp problem, thereby wasting valuable time and resources.
3. The remedy implemented might only address surface symptoms of a deep-seated problem.
4. The remedy devised may exacerbate the damp problem.
5. Another damp problem local to the flagged up issue may not be discovered.
6. And a surveyor that merely flags up a damp issue could be held legally liable for not following the trail of suspicion. Law Case: Roberts v J Hampson & Co (1989) [3].

The above outcomes would incur unexpected costs to the property owner, as well as wasted time and of course unwanted disturbance and stress.

The key point is that if it is not possible in an initial survey to properly diagnose a damp problem, it would be helpful to clients if the same surveyor could either extend their survey on the day for a top up fee or arrange for a further and more thorough examination of the problem on a later date – or if necessary by another party with the appropriate knowledge and experience. Chartered surveyors (especially building surveyors) ought in my opinion be able and willing to inspect standard damp problems sufficiently to achieve a reliable diagnosis, having been given the time and opportunity they would need to do that.

1.2 The common types of dampness investigation

Further investigation commissioned by the buyer following a pre-purchase survey.

This type of investigation often arises because a pre-purchase surveyor has flagged up a damp problem – usually from having obtained higher than expected damp readings on joinery or a plaster finish – but does not progress investigation further to diagnose the problem. In a pre-purchase survey – whether the briefer ‘homebuyer’ format or the fuller ‘building survey’ – a house surveyor will inspect the whole building and comment on its services, and often any outbuildings or boundaries too. This is quite a broad remit, so there will not be the time available to fully check out a damp problem. In addition, there may be a limitation on how much ‘invasive’ inspection might be allowed, as the vendor might be reluctant to have the property even slightly marked or damaged. This further investigation can be by the original pre-purchase surveyor, an independent dampness consultant or most commonly by a remedial work specialist, the latter often introducing commercial bias to the investigation.

Further investigation required by the vendor following problems in a property sale.

This client will have probably marketed his or her property for some time, and at least one sale may have fallen through because the buyer has discovered a damp issue to be significant and requires a considerable financial outlay to resolve. Or perhaps the buyer may have obtained a high quote for remedial work and has used the quotation to try to renegotiate a significantly lower purchase price. So the sale might be jeopardised. Faced with difficulty in selling, the vendor then seeks to obtain his or her own damp report and quotation, so this could be presented to any future buyer to allay fears concerning the damp problem. The vendor could also choose to carry out the work before re-marketing. Either way, an investigation and report ideally by an independent investigator would carry much weight and help propel the sale forward.

Investigation of a specific damp issue commissioned by a private property owner in residence.

There will be here the advantage that the owner will more often than not have paperwork available concerning quotes for work or specification of work already carried out. At the beginning of the dampness investigation, the owner will often go through a very detailed history of the damp problems. This will help the investigator make sense of the damp problems.

These investigations are a little more relaxed as a rule. The client would usually not press for an urgent inspection.

The common scenario is when defects do not show themselves until some time after the buyer moves in to a property, and there are a number of reasons for this. One common reason is that symptoms have progressed to be more evident than when the property was first viewed. Typical phases of defect progression are explained in Chapter 2 Home buyers often notice symptoms of a damp issue that only surface a year or two after the property purchase and sometimes because symptoms had been purposefully decorated over by the vendor prior to the sale.

Investigation of a specific damp issue commissioned by a tenant in situ.

With a tenant in situ, you would most often be able to obtain a detailed history of the subject damp problems.

Investigations for tenants (or landlords) can be rather tricky. For example, a landlord will often suspect condensation and mould issues to have been brought on by ‘lifestyle issues'. While the tenant will commonly consider building or services shortcomings the root cause of condensation and mould. But most condensation and mould problems are the result of a combination of factors. For detailed information on condensation and mould issues, please refer to Ref [1], Chapter 3 and Ref [2], Chapter 7. When a tenant commissions a dampness consultant to inspect and report on condensation, or mould particularly, there may be an expectation for a particular diagnosis – eg that there is mould that is a health risk and it is the fault of the property manager or landlord – and failure to produce such a conclusion from the dampness investigation might be a cause for considerable disappointment for an often financially hard-pressed tenant. Remember that the fee for a dampness investigation will probably be much harder for a tenant to bear than for a landlord. So always make it clear that the diagnosis cannot be predicted before the inspection – or to put it bluntly:

You can’t buy a diagnosis!

Investigation of a specific damp issue commissioned by a property manager/landlord.

If a property manager or landlord has commissioned a thorough dampness investigation that would carry good fees, then the property manager would be clearly taking the problem seriously.

There may or may not be an occupier at the premises. If not, it is always wise to obtain as much information as possible pre-survey regarding the history of the damp defects.

And always be sure that anybody allowing you access into a property, or an occupier in situ is fully briefed concerning how much time your inspections might need.

Investigation following a complaint from a neighbour regarding dampness to a party wall.

When a property owner or occupier notices a damp patch on a party wall, the natural reaction will be for the individual to suspect the source is from next door. They may suspect past building work next door that seems to tie in time wise with the onset of the damp problem. They may visualise an issue concerning a shower room or bathroom on the neighbour's side – or how the property next door is neglected or was flooded some time in the past. You may find yourself in a difficult situation if your client aims to prove damp is sourced from a neighbour's property, when you actually find that is unlikely to be the case. Your report may not be well received – and even an acknowledgement of its receipt may not be forthcoming! There may be a worrying silence; your poor client may be crestfallen having spent several hundred pounds or more finding out that they are actually to blame for the dampness problem! I tend to tak...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Contents
• Schedule of case files
• List of sketches and diagrams
• List of tables and boxes
• Acknowledgements
• Abbreviations
• 1. Introductory matters
• 2. Guidance on the common damp problems
• 3. Case files
• 4. Leak detection
• 5. Infrared thermography
• 6. Step by step guides of site inspection techniques
• Glossary
• References
• Appendices
• Index