Moisture Mapping Large Commercial Buildings
When a large project is won by a smaller company, one of the items often overlooked is proper documentation of the drying process. Most companies are used to doing smaller commercial jobs routinely. However, when something on the order of a multi-story hotel shows up, the sheer size of the project and required timeframe by the owners, who want little to no downtime, overshadow the time allowed for detailed documentation. As such, the documentation is often left to waste. This is a huge mistake! When the hotelier wants to re-negotiate the bill after you are finished, you may have trouble proving the services provided (the scope of work). Now you are negotiating from a bad position, possibly without sufficient proof to fight, probably leaving you vulnerable in arbitration or court.
The S500 requires us to take daily moisture content readings and states that we should be charging for the labor to obtain this documentation. The concern on a large project is that highly detailed readings that you’re used to taking in a house can be very labor intensive, expensive and difficult to follow on a massive project. I have seen some reports that are more than 200 pages thick, but that is far superior to the many moisture maps I have seen when the restorer puts the readings on the fast food napkin from lunch!
Depending on the project size, wall and subfloor construction, as well as the degree of detail desired by the customer, you may want to look into one of several different tracking methods to prove the building is restored to its previous “healthy” or normal Equilibrium Moisture Content (EMC).
For more than 24 years now I have used both the highly detailed moisture content mapping, (one page per room per day) as well as a more preferred system in the larger loss arena, a medium detailed moisture map (one page per floor or area per day). Always allow the customer to choose, explaining the cost and time differential to them. This shows that you are looking out for their well being and cash as well as your own.
This highly detailed system, provided by the Hydro Lab and designed by Kurt Bolden and Mark Wichem, uses a graph and symbol system to lay out the floor and wall plan and is set up to take care of one room or small area over six days. There are many variations on this theme, but this is the most efficient one I have used. (Please note: You are not allowed to reproduce this specific mapping system without the designer’s approval.)
Less detail is found in the Commercial Color System (Figure 2), but it is designed to be more than sufficient enough to prove drying times and moisture readings as long as all parties agree to its use. Generally, this mapping system is for concrete-floored buildings that are wet for less than three days with gypsum wall board and either metal or wood framing (wood framed and/or insulated walls require field notes indicating how wet the sill plates are and insulation and metal framing requires inspection for water retention). Wood floors and subfloors, plaster walls and complex or historic structures should always use the more highly detailed system. Also, this mapping is not directly supported by the S500, so to be clear, you need to get signed permission acknowledging that you are approved to use this by the customer(s).
If the parameters of the project allow for this medium detailed documentation, then ask for a set of floor plans or a simple fire escape diagram, reproduce it on letter size paper or scan it into a software program that allows you to highlight areas and place notes on it. Using four basic color codes - RED for affected materials above 16% Wood Moisture Equivalent (W.M.E.), YELLOW for areas between 16% WME and your Normal Equilibrium Moisture Content (Dry Standard), GREEN for areas that have been restored to their respective dry standards and finally PURPLE for materials that are to be removed and replaced. Highlight the sections of wall with color according to the moisture readings taken there.
To do this in the fastest time, use a telescoping painter’s pole with a threaded end. Place your probe on the end of the pole (threaded units are available from Delmhorst and Extech, consult with your provider) use an extension cable from the probe to the meter (if needed) and test in several spots along the wall as another person highlights the proper color on the wall diagram. This takes less than 30 seconds per wall and drastically reduces bending over and climbing ladders.
Others I know have taken this one step further, using thermal imaging cameras for daily monitoring (recording the images each day) and taking MC readings with penetrating meters for initial and clearance monitoring. Remember, short tip penetrating and most scanning meters only read one layer of drywall, so always look out for multiple layered walls even if they are not firewalls.
In the notes section, describe your color-to-moisture content scale, general description of building construction (i.e., uninsulated interior wall with vinyl cove base latex painted 5/8-inch drywall over metal framing, not “rock on stud”), how high or up the wall moisture has migrated (Class) and, of course, finally the category of water.
A concrete floor that has had water on it only for a couple of days and is not wet from ground flooding, hydronic heating systems or other leak penetrating deep into the concrete, the floor will generally return to its normal EMC within the time that it takes the structure to dry down. You can use scanning concrete moisture meters for readings and color a dot on the area of the floor plan indicating its condition daily.
Remember, most scanning meters only measure about the top half inch of concrete, so you can never say it’s dry enough for flooring until someone has done an acceptable ASTM test. When using scanning meters on the relative or qualitative scale, all you can say is the top is reading the same as the unaffected concrete. Besides concrete is never truly dry, at 75% Equilibrium Relative Humidity it’s just barely dry enough!
There are now commercially available software programs allowing you to do this recording electronically, such as Moisture Mapper and RestoReports. Some software systems allow merging with billing and estimating programs. I advise you to look into them as a possibility. Remember, always print out a hard copy as the “blue screen of death” can visit anytime and you may have nothing!
Hope to see you at Connections this September in Las Vegas. And as always, happy drying!