Moisture mapping, an ideal article for damp specialists, water damage practitioners or just budding surveyors.
October 23rd, 2019
Moisture mapping is a vital discipline and skill which really is essential to every water damage practitioner or building surveyor who specialises in damp diagnosis. If you’re a budding surveyor just starting out in the industry, this post really is for you. Learning the basics of moisture mapping now and practicing these skills over your career will ensure you have a much higher success rate of accurate diagnosis.
So, what is moisture mapping?………..
Moisture mapping is the process of collecting instrumental measurements from a structure and plotting the recorded data to assist in either diagnosis or repair.
In the preservation industry moisture mapping is often referred to as profiling and is used similarly to profile or plot the distribution of moisture or salts through a structure. The pattern of readings can then be interpreted in the aid of diagnosis to ensure you accurately locate the source of moisture. Profiling in the preservation industry is often undertaken on walls and floors or even directly through a structure.
In restoration this same technique is used to monitor buildings following a flood or escape of water incident. Mapping the building at the start of the process provides an insight into what parts of the building are affected by water and to what extent. Taking measurements from another region within the structure unaffected by moisture, crucially of the same method of construction also provides a drying goal. A drying goal is a target measurement which is used as a comparative to return the affected materials to. The affected materials are considered dry when their instrumental readings match those of the drying goal (or unaffected parts of the structure). We consider this returning the building to its pre-loss condition.
Repeating the moisture mapping process throughout the drying phases also allows progressive monitoring of the building. This provides vital information as to how the building and materials are responding to the drying conditions and how easily moisture is being released. Monitoring the atmospheric conditions during this process also provides valuable information on how balanced the atmosphere is during the process and how effective the drying regime is.
MOISTURE MAPPING EQUIPMENT
The type of instrument you use isn’t a crucial as you might think, providing the method and instruments used are consistent. Therefore, it’s doesn’t matter whether you use a Protimeter -SurveyMaster, Tramex – Moisture Encounter or Flir – Pro MR60. Providing that you stick with the one instrument consistently through your mapping process, the results are comparative to that device. You should never compare the results of one meter to another.
Electronic moisture meters unfairly receive a lot of bad publicity for being unable to provide quantitative data when used on masonry. This however, as you’ll learn to understand isn’t as important as it may seem in many scenarios. Only in the event that the material you are testing is either contaminated or impaired by an electronically conductive material would this provide real cause for concern.
For more information on how electronic moisture meters work, their advantages and disadvantages, you may find the article below useful:
When learning how to moisture map, it’s essential that your method of record keeping is as good as your process of measurement taking. Being able to record the instrumental data in a process that is methodical, consistent and legible is key. You should therefore develop a system that enables you to record this data accurately.
By referring to industry acronyms for instrumental readings you’ll be able provide an indication as to what instrument was used and their relationship to the material being tested.
Here’s an example:
Electronic moisture meter– measurement pins used on timber – WMC (Wood Moisture Content)
Electronic moisture meter– measurement pins used on masonry – WME (Wood Moisture Equivalent)
Electronic moisture meter – scan mode on masonry – digital – RF (Radio Frequency)
Electronic moisture meter – analogue impedance meter – FSD (Full Scale Deflection)
Calcium carbide meter – % M.C (CC) – % Moisture Content (Calcium Carbide)
Gravimetric Analysis – % T.M.C (OD) – % Total Moisture Content (Oven Dry)
It’s important to remember if you’re using the gravimetric process you must state whether your results refer to TMC (Total Moisture Content), F.M.C (Free Moisture Content) or H.M.C (hygroscopic Moisture Content).
By using the correct acronyms (above) your method of record keeping will record not only the instrumental readings but also their quantitative / qualitative relationship to the material tested.
Some instruments are calibrated for certain materials therefore it makes sense that if you have equipment calibrated specifically for concrete or timber, then obviously, it’s always best to use these.
In my business we use multiple different methods of data recording for moisture mapping and these vary dependent upon the circumstance and material involved. Because our business crosses between both preservation and restoration, we need systems in place for both aiding diagnosis during our surveys but also for record keeping and monitoring during ourwater / flood damage projects.
Here are two examples of record sheets that we use for recording data during surveys:
1: Example record sheet for floor and floor screed inspections. We use these record sheets when testing newly placed floors or screeds for drying.
2: Example record sheet for water damage inspections. An example of a basic record sheet used to record measurements from different locations during a water damage incident.
So, lets look at how moisture mapping / profiling can be used to aid diagnosis?…………….
Let’s use the average wall that exhibits symptoms indicative of rising damp.
We’ll start at one end of the wall and take our first reading using whatever chosen device from the lowest accessible location of the wall. Usually this will be the skirting boards, and if present they’re ideal, particularly if your instrument is an electronic moisture meter calibrated for timber as this reading will be quantitative.
We’ll then proceed to take readings from the base upwards at increments of 100mm or 200mm and take note in the change or deviation of the instrumental readings. As mentioned before, if you start taking readings using surface pins, you must continue to use the same technique for your entire profile if the material is the same.
Repeating this process at intervals across the wall will then provide you with a catalog of data which can be used to aid your diagnosis.
I’m using a profile of rising damp in the example below as the data is relatively easy to demonstrate and interpret, remember this is supposed to be educational.
Here’s an example of a wall displaying symptoms of damp that’s been profiled up to the height of 1.5 meters above internal floor level and at 1 meter intervals along the length of the wall. We’re going to call this wall A. The readings taken from the wall’s surface are recorded as WME to indicate the readings have been taken from masonry using an electronic moisture meter using surface probes.
As can be seen in the example above, the wall displays high moisture levels record within the skirting boards entirely across the wall. The profile of reading also emanates from the base of the wall and then terminates with a slight decline between the heights of 500mm and 750mm. This is a profile consistent with rising damp activity.
You can also display the walls profile in a cross section diagram as shown below.
Admittedly, at present the profile doesn’t complete the diagnosis, it simply aids to provide a record which can be reproduced into an aid and prompts further investigation.
So, if the above scenario presents a rising damp profile you now need to investigate the following;
– Is a damp proof course present? original or retrofit?
– Is the damp proof course positioned appropriately in relation to the ground externally?
– Is the damp proof course positioned appropriately in relation to the internal floor structure?
– Is the damp proof course compromised by the plaster internally or debris within the cavity
– Has the profile been taken using a quantitative method? If not, then ideally quantitative assessment should be undertaken to ensure the results of the qualitative inspection are accurate.
– Etc, etc………
Mapping the profile in the above scenario will however point you in the right direction to investigate possible causes.
Following are images of walls being profiled using a variety of methods.
Images of a site investigation – profiling a wall using the calcium carbide process.
Images of a site investigation – profiling a wall using the gravimetric process.
So, lets look at an example of profiling through a structure.
Moisture mapping through the composition of a structure, a floor in this scenario is a good example. Floors construction is often much more complex than a wall as multiple layers of different materials can exist which can often be separated by multiple damp proof membranes. This is often the case with floating floors or floors which incorporate under floor heating systems. If any of these damp proof membranes fail, identifying the source can be extremely difficult.
Below is an example of a profile taken through a floor’s composition, in this case a floating floor with underfloor heating.
You will note than I use an electronic moisture meter to map through the various layers of the floors construction however, then use a calcium carbide meter to sample the final concrete base. This is fine as long as I use this method consistently when profiling another section of the same floor and is beneficial as the calcium carbide reading is quantitative, providing no salts are present.
Top left – bottom right – WME readings from the surface screed, WME readings from the cement board, WME readings from the insulation, C.C readings from the concrete floor structure.
Repeating this process accross the floor will allow you to create a map of not only the affected floor area but also the materials through the floors composition.
ADVANCEMENTS IN TECHNOLOGY
As the process of moisture mapping involves repeatedly taking samples or instrumental measurements through or over a surface the procedure can be time consuming however, advancements in new technology have improved the speed and accuracy of which buildings can be mapped or profiled.
Thermal imaging is a significant advantage in the water damage industry as in most cases thermography allows a quick an easy visual assessment of which parts of the structure have been affected. This allows your profiling regime to be concentrated to the affected locations, saving time and money. In this scenario profiling is generally only used to asses the degree of saturation rather than determining the area affected which can be seen in the thermogram. It is however, important to remember that thermal imaging does not provide quantitative data regarding the moisture content of the materials affected, it merely provides a thermal representation across the structure. As such this should not be used as an alternative to moisture mapping or profiling. Verification of the thermal image will still need to be undertaken with a moisture meter.
For an easy way to combine a visual, in addition to instrumental readings perhaps try looking at Tramex’s Moisture Mapping software. For anyone who’s recently purchased one of Tramexs’ new moisture meters the CME5 or the ME5 you’ll notice that the new devices include a Bluetooth feature. Another gimmick I hear you say, but no, just wait!
The Bluetooth feature on these new meters allows readings taken to be embodied directly onto a floor plan or visual image in a methodical method with the use of a super imposed grid. The location on the grid can also be colour coded to represent the measurements taken. The combined use of these instruments and the software provides a fast and professional way to depict, document and assess the moisture conditions. They are also a means of archiving vital information for reference in future
Furthermore, moisture maps such as these allow the user to clearly visualize the water /moisture migration and define dry areas from wet areas, and the varying degrees of moisture across the map. The surveyor can clearly record each reading for each segment of the affected area and record repeated readings for the exact same grid segments, throughout a drying process.
The software also allows the moisture maps to be extracted and included within a report, along with any other documentation, serving as a communication tool between you the professional, the client, the loss adjuster and the insurance company.
If you haven’t had the opportunity to use the moisture mapping software produced by Tramex I would highly recommend it. You don’t require the most up to date moisture meters with bluetooth to use it as the map can also be created with manual input, so why not give it a try.
I’ll leave a link to the download below:
Finally, I hope you found this article useful and informative and if you have any questions or queries about these subjects please don’t hesitate to get in touch.
If you would like to learn more about moisture mapping or damp diagnosis you may find the following articles useful:
Moisture Content Analysis – //www.dryfix.net/blog/explained-moisture-content-analysis-using-the-gravimetric-process/
Calcium carbide Meters Explained – //www.dryfix.net/blog/damp-diagnosis-calcium-carbide-meter-speedy-meter/
Russell Rafton – Dryfix Preservation Ltd Senior Surveyor
Dryfix Yorkshires Leading Damp & Timber Specialists
A 4 x Industry Award Winning Company with the Property Care Association.