Damp investigations

This section aims to provide you with the necessary background knowledge on general surveying practices – including preparing for surveys, the use of equipment, and features that you should be looking out for.

Good and comprehensive advice on all aspects of the inspection of building elements – roofs, walls, floors and so on – can be found in Professor Malcolm Hollis's book Surveying Buildings. The purpose of this section is to home in on specific issues that relate to dampness investigations.

The goal of a dampness investigation is to identify any 'significant' dampness and decide what, if any, action needs to be taken to either manage it or cure it. During the course of an investigation you need to use all your senses – sight, touch, taste, smell and hearing – as well as your communication and analytical skills. You may even need to demonstrate your physical agility – climbing ladders, peering under floorboards, or squeezing into corners. You certainly need to be proficient with a range of specialist equipment; you will often have to conduct tests or take samples for testing at a laboratory.

The surveying process is relatively simple, as illustrated by figure 1.

Figure 1: The surveying process

Preparation

Pre-inspection procedures are described in detail in Building Surveys of Residential Property, where the importance of desktop research and initial reconnaissance are stressed.

Good pre-planning of the inspection is essential in a dampness investigation.

Before the survey proper begins, obtain an insight into the basic house construction and perhaps the age of the building from the initial briefing. This information enables you to plan the survey in terms of time and equipment needed, and to engage any specialists or general assistance on site.

Desktop research before and after the survey can unearth valuable information concerning the building in question, similar buildings and the local environment. The internet can provide information on a range of potential property threats, with guidance on the likelihood of flooding being particularly useful in the context of a dampness investigation.

There is also a lot to be gained from talking to occupiers, owners, neighbours or other locals. All may well offer invaluable insight into particular defects, or construction styles or materials used, or the general history of the building and locality. However, be mindful that there can often be a distinct difference between the kind of information you might glean from a seller of a property compared to what you hear when your client is the occupier of the premises. Sellers may not offer full information, whereas an occupier interested in finding out the building's condition for their own benefit may offer the full history of the building, its defects, construction work and surveys previously carried out.

Considerable information may also be obtained from local contractors, if building work is in progress nearby. A local contractor will be familiar with the construction materials typical in the area, and may have undertaken excavations for foundation work or drainage which will give an insight into subsoil conditions. Local building inspectors will also be able to offer considerable insight into common defects to the type of building you are to inspect.

If you are to survey an empty property, establish prior to the survey whether there is sufficient light and power available in the property for the survey. If not, take the necessary steps to ensure that the survey can be properly and safely carried out (see Surveying Safely).

Remember that dampness problems in terraced or semi-detached houses can easily be sourced from an adjacent property, or can indeed be sourced in the subject property and affect a neighbouring property, so it is prudent to consider whether you will need to gain access next door. Surveys of flats often require an inspection of adjoining units where, for example, liability for repair of main building elements or services might be shared, or dampness may travel between units. Surveyors should also give consideration to relevant party wall law (see Party wall legislation and guidance, 6th edition and Anstey's Party walls).