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The Art of Inner Wall Sampling Part III

 

INNER WALL SAMPLING FOR MOLD SPORES PART III OF IV.

THE LOGIC AND EFFECTIVENESS OF INNER WALL SAMPLING

Based on eight years of inspection and testing for mold, it has become obvious to this mold inspector that inner wall sampling for mold problems is very effective. Inner wall sampling is one of the best ways to determine if mold is a problem in a given wall cavity. The first step to take prior to sampling in a wall is to locate a moisture intrusion problem at that wall; this should explain why mold would be in the given wall. If you have elevated spore levels in a wall and moisture damage on or near that wall, then it is reasonable to assume that the reason for elevated mold spore levels in that wall only because of mold that grew in that wall.

Also look at the types of spores; if you have Stachybotrys, Memnonella, Chaetomium, Aspergillus niger, Trichoderma or other spores produced by molds that require lots of water, then you know the mold in the wall not only likely grew in that wall if these same spore types were not found to be elevated outside the wall. But we also know that these mold must have grown as the result of the water intrusion into that wall.

People do not argue with the above logic unless of course money is at stake. You see, if a lawsuit or insurance claim is at stake then and only then do people argue with the simple logic and common sense of inner wall sampling.  Below are arguments against inner wall sampling.

 

 

FIRST ARGUMENT AGINST INNER WALL
THE DIRTY WALL EXCUSE
The argument has been given that if spores are in a wall they may be from growth that resulted because of dirty conditions in the wall. Such persons will argue that during construction builders toss empty cans in walls, and sawdust and dirt and other debris are left in wall voids.
 

ANSWER TO THE DIRTY WALL EXCUSE
It is true that debris can be found in walls; however, this argument is incredibly, ridiculously and utterly un-scientific. No amount of debris or other food source for mold ever caused mold growth in a dry home or dry wall. Mold in homes and in walls is never in need of more food in the form of debris for mold to grow. Mold in buildings is always in need of water. If mold is growing in a wall, it is because of water in that wall. 

Look at the types of items drywall contractors and wall framers leave in walls during construction. It is true that these items can serve as food for mold including short sections of Romex wiring, short sections of PVC, CPVC, and copper piping, small pieces of wood and metal truss materials, and the occasional soda can. All these items can be found at your local Home depot. Lets do an advanced scientific experiment in our heads, lets pretend we are visiting a Home Depot go to the plumbing section and look at the copper pipes and the PVC pipes, go the the electrical section and look at the wiring, go to the lumber section and look at the wood, now go to the check out lane and look at the soda in the small frig, how much mold did you see, perhaps none at all, perhaps a very few very tiny colonies on some lumber that grew at the lumber yard. You will not find any mold problems at these items in home depot nor will you find mold problems on these same items in the wall. The reason is because water is a limiting factor, you do not have adequate moisture in a home depot for mold unless the store is ripped to pieces in a tornado or hurricane, or unless it's roof is leaking. in the same wall you are not going to find mold on construction debris in a wall unless water intrusion occurred and provided water for mold to grow in that wall.        

How do we know this is true? Well, it is common knowledge that water is the limiting factor for mold growth in buildings and in walls, and not food. Take away water--mold will not grow; provide water and it will grow. Providing a food source such as dirt and sawdust and construction debris in a wall will make no difference at all because wall cavities already have adequate food in them in the form of drywall paper, dust, and very often wooden studs and wooden sole plates.  If all mold needed was dry dust and dirt for growth to start, then dusty dirty deserts would have mold problems.
 

THE SECOND ARGUMENT AGINST INNER WALL SAMPLING
RAIN DURING CONSTRUCTION
What about mold resulting from rain falling on wall studs or other building materials prior to or during construction? It is possible for rain during construction to cause mold in the wall.

ANSWER 1 TO POSSIBLE RAIN DURING CONSTRUCTION
CONSTRUCTION OF ROOF EARLY IN THE PROCESS
Construction time rain can theoratically cause mold in walls, but it is not at all likely to cause a problem in the real world because of many reasons.

The first reason that rain does not typically cause mold in walls during construction is because the roof is put up very early during construction. The roof is put up long before the drywall is installed; this is no accident, your builder does not want the entire neighborhood suing for mold damages so he puts the roof up early to help deter rain from wetting walls long before drywall is installed. Also, during construction, wooden studs and plywood floors etc, are typically allowed to dry before building materials are installed. Most builders do not put drywall over wet studs because they do not want to be sued the next year.

I have conducted mold testing in Miami, Kendall, West Palm Beach, and Stuart, many times between 2003 and the present, including thousands of inspections for mold in all of Palm Beach, Dade, and Broward Counties. Only very few times I have seen cases where mold occurred because of rain during construction, one sever case was in a 50,000 sf Bank in the Florida Panhandle, this bank had been hit by multiple hurricanes during construction, and roof parapet wall construction was delayed about a year because the builders could not locate some type of capstones due to hurricane related delays.

I have seen it happen to a few homes mostly between Vero Beach and West Palm Beach during and shortly after hurricanes Wilma, Francis, and Gene, hit in around 2005. Unless something drastic happens like a hurricane or two or three in a row, it is unlikely that wet building materials was the cause of mold in your homes walls. I have conducted thousands of mold inspections and always investigate cause and origin and have found when mold is in a wall, it is because of a specific defect in the exterior side of that wall, or because of a plumbing leak that occurred nearby inside the home. Thus in my experience it is beyond a reasonable doubt that if mold is elevated in a wall, then that mold likely grew in that wall and did not likely occur as the result of rain during construction.    

ANSWER 2 TO POSSIBLE RAIN DURING CONSTRUCTION
TIMELINE OF HEALTH RELATED ISSUES
At rare times rain may wet walls during construction, and a careless builder may install drywall before dry out is complete. This is theoretically possible but not likely to happen because the roof is installed before drywall is installed. If it did occur, then any client health complaints should have started within minutes or hours of the client taking up occupancy in the property. If the health complaints started weeks, months, or as is almost always the case years after occupancy, then it is not very reasonable to conclude that the mold problem discovered in the walls started during construction rains. In other words if mold was the result of construction time rain, then the mold should have been present since day one and the occupant would have been sick since day one.   

ANSWER 3 TO POSSIBLE RAIN DURING CONSTRUCTION
TIMELINE OF DAMAGE 
Often water damage will occur on the surface of the wall; damage may be in the form of the baseboard separating from the wall, or in the form of paint wrinkling, warping, or peeling. If the mold was the result of rain that occurred during construction, then the water damage should have existed from the start. However, client interview information will typically show that water damage occurred much closer to the time of the inspection.   
 

ANSWER 4 TO POSSIBLE RAIN DURING CONSTRUCTION
REVIEWING CONTROL SAMPLES FROM OTHER WALLS
To provide evidence against such conclusions regarding mold starting during construction rains, an inspector can take a control sample from a non-suspect wall or two for comparison to suspect walls. This can be done long after the initial inspection. If a suspect wall reveals elevated spore levels and a non-suspect wall reveals levels and types similar to indoor air spore levels and types, then it would only be logical to conclude that that suspect wall has a problem with mold, and that problem is not likely from a widespread issue such as rain during construction. If mold in walls started as the result of construction time rain, then walls throughout a home should be equally moldy.

ANSWER 5 TO POSSIBLE RAIN DURING CONSTRUCTION
REVIEWING CONTROL SAMPLES FROM THE INDOOR AIR
In order to show that a problem came from inside the wall that you obtained a sample from, you can compare the spore levels in the wall to spore levels in the indoor air. If levels in the wall are higher than levels in the surrounding indoor room air, then it is likely that the mold in the wall came from within the wall and not the surrounding air.  
  Click here for information on this inspectors personal experience with inner wall sampling.
  

ANSWER 6 TO POSSIBLE RAIN DURING CONSTRUCTION

IT DOES NOT HAPPEN OFTEN
If the combination of rain and building construction was likely to contribute to mold issues then each time it rained, buildings under construction would become moldy and virtually every building outside of arid deserts would be excessively moldy as a result. Virtually every builder must have constructed buildings and had precipitation fall during construction, but we do not see every builder being sued out of business, and we do not see every inner wall void full of mold during inner wall sampling. Our mold testing experience shows that though it may happen at times, it is a rare condition, we have to give builders credit for knowing how to build buildings without them becoming a mold haven each time it rains.