Cap and Boots (VI)

So far in this look at some of the challenges facing buyers and owners of older homes we have looked at the roof and foundation, the plumbing and wiring, and then a couple of toxins commonly found, lead and asbestos. Both of those hazards are natural materials which, because of certain desirable qualities, have been utilized by industry to create a ‘fantastic’ range of products, and as a result are found in larger-than natural concentrations in many homes. There are more hazards yet however, and in today’s post I wanted to look at another potential toxin that has little to do with industrially-produced materials – this one is entirely natural.

If the house has a primitive foundation, and moisture in the soil, it is very likely that mold will also be present. If a house has a leaky roof, or blocked gutters, and/or suffers from ice-damming, the space under and around the roof deck will tend to have a significantly higher moisture level than normal, and that can promote the growth of mold. Some houses have poorly installed bathroom fan duct work putting moist bathroom air directly into the unconditioned roof space, and you can be sure to see mold sooner or later. Faulty plumbing is another major culprit. If air circulation in damp areas is lacking, then it is even more likely that the house will suffer from mold problems. With all things being equal, cooler temperatures will lead to a higher relative humidity percentage, since cooler air is able to hold less water before condensation occurs. Of course condensation means moisture. Finally, a lot of modern houses are so well sealed with plastic vapor barriers and caulking that interior sources of moisture and humidity can lead to some fairly grievous problems

Molds are parts of the natural environment and serve an utterly critical role in the breakdown of organic matter, such as fallen leaves and dead trees, etc. Inside the home however, molds are not so welcome or helpful. Taken right from the EPA:

Molds are usually not a problem indoors, unless mold spores land on a wet or damp spot and begin growing.  Molds have the potential to cause health problems. Molds produce allergens (substances that can cause allergic reactions), irritants, and in some cases, potentially toxic substances (mycotoxins).  Inhaling or touching mold or mold spores may cause allergic reactions in sensitive individuals.  Allergic responses include hay fever-type symptoms, such as sneezing, runny nose, red eyes, and skin rash (dermatitis). Allergic reactions to mold are common.  They can be immediate or delayed.  Molds can also cause asthma attacks in people with asthma who are allergic to mold. In addition, mold exposure can irritate the eyes, skin, nose, throat, and lungs of both mold-allergic and non-allergic people.  Symptoms other than the allergic and irritant types are not commonly reported as a result of inhaling mold.

Mold commonly propagates in a hidden manner and it may be quite a while before problems are detected. A first sign would be mildewy smells or a rise in allergic reactions among house dwellers. According to a 1999 Mayo Clinic study, nearly all chronic sinus infections (afflicting about 37 million Americans each year) are a result of mold.

In some houses the mold problems can reach epic levels and become a deadly hazard to the inhabitants. One account I read of involved a house in South Carolina in which one particular mold Stachybotrys, the so-called Toxic Black Mold,” had taken over:

The mold had built up to such levels that the owners abandoned the house, fearing for their daughter’s safety:

Leventis and his family were the first to discover the horrible secret of Number 6 Whitten Street. There is no indication the previous owner was aware of any mold.
“I’ve never seen my kids that sick. And it was scary,” Tricia Leventis said in tears. According to Tricia, she and their two young daughters became desperately ill, and said doctors told them to leave the home immediately.”It was adamant. Absolutely, get out,” Leventis said. “It was to the point where my youngest was so sick, she was unable to hold any nutrition, nothing was working, she couldn’t breathe.”The Leventises did the only thing they believed they could do, with no money in savings to have the mold removed. They stopped paying their mortgage and let the home go into foreclosure.

The foreclosed house was later re-sold to another couple, the Brown’s who eventually discovered the house’s secret.  A lawsuit followed.

If you look around the wwweb you can find some truly horrific pictures of household mold problems, especially from companies offering mold remediation services, like this one:

The toxic black mold Stachybotrys chartarum may associate to childhood respiratory distress, though a link remains to be proven apparently. Evidence does appear to be mounting however, according to one paper I read by University of North Dakota Professor of Plant Pathology, Berlin Nelson, in a February 1999 article entitled Stachybotrys chartarum: The Toxic Indoor Mold. Another site with a wealth of information on this topic is

If the house does have mold, the immediate action to be taken is to reduce humidity levels, eliminate the causes of higher moisture in the home, and remove all affected materials. This can get quite expensive, and in the case of many houses, it may well be cheaper to bulldoze and start again. A few molds can be killed by cleaning the moldy surface with chlorine, however this is ineffective against the worst forms of mold. According to the site,

…stachybotrys often has a germ mycelium that is buried inside the water damaged surface that is often inaccessible to chlorine. In fact, bleach often does not kill Stachybotrys entirely when directly applied to it. Changing the humidity may lead to limited death of the stachybotrys colony. However, changing the humidity may also induce heavy sporulation. Burning the building that has undergone stachybotrys contamination has been an idea of many people but some experts state that not even a fire of 500 degrees could destroy the spores of this deadly enemy. If anything, it could spread it and worsen the condition. The ground around these buildings can also become heavily contaminated with stachybotrys from a sick building. It is recommended that the ground (dirt) be removed at least one meter prior to rebuilding any new foundation.

Imagine that – you can burn the house down and still not get rid of this fungi! It’s tenacious.

Bandaid solutions of spraying anti-fungal chemicals and using ‘anti-mildew’ paint over affected areas are largely doomed to failure though it is not an altogether uncommon strategy by those seeking to sell a diseased house. It definitely pays to have a detailed home inspection done, with a check specifically for mold. For those owning an older home, to avoid mold problems before a potential catastrophe occurs, the building should undergo scheduled maintenance that includes inspection for water leaks, problem seals around windows and doors, as well as checks for visible mold in moist or damp parts of the building.

Perhaps I am overly cautious, but when I see stuff like this…

…I’m not thinking ‘fixer-upper’. I’m thinking, ‘run’. And I’ve been looking at a lot of real estate listings over past months and there is no shortage of houses on the market with mold problems or houses which have had ‘mold-abatement’. I’m not optimistic that the abatement will be anything other than a stop-gap measure in the majority of cases, as it simply costs, for many home owners, far too much money to fix the problem when foundations and roofs are involved. There are also a huge number of homes on the market right now which have been foreclosed upon and then sit empty for months and even years. Once a house rides through the winter with no central heating, things inside take a turn towards dampness, and I can’t help but suspect a large number of homes will transition from ‘inhabitable’ to ‘scraper’ just from sitting unoccupied.

Next time I’ll conclude my look at old house ailments with another entirely natural and common pathogen. Thanks for coming by the Carpentry Way. Comments always welcome, and here’s hoping you have mold-free weekend.

3 thoughts on “Cap and Boots (VI)

  1. We have mold in the tile grout in an upstairs bathroom and some affecting the trim on the window.
    There is a ceiling fan and a window to open, but in the wet months it's hard to imagine conditions ever really drying out enough for mold not to take hold here and there.

    I'm wondering what to do. If a 500 degree fire won't get rid of it… perhaps jettison the tiles and replace with solid surface material. How about the painted trim? Scrape off and start over? Are there paints and varnishes that are especially resistant to mold?

    Thanks for this post.

  2. Tico,

    thanks for your comment. The bad news here is that if you see mold on the surface of tile grout or trim, there is good chance the moisture has penetrated the grout and has been absorbed by the board behind the tile, and is well into the trim material. Hopefully you have the water resistant cement backer board behind the tile, as paper-based boards are attractive to mold. If the mold is extensive you may be faced with taking the bathroom down to the studs in a repair effort.

    So, how to deal with the situation?

    Once you've removed all mold-affected materials, or materials which would be attractive food sources for mold, then you are well on your way to job #1, eliminating the food source for mold. When you replace materials in the bathroom, select those which are not going to be mold-friendly. There are fiberglass-faced backer boards for example.

    The primary moisture source in a bathroom is the shower, so if there is any way you can re-design the space so as to make the shower and toilet separate from the rest of the bath, you make the load of moist air to be exhausted much smaller. Make sure that the fan is of adequate capacity for the size of space and that it vents to the outside. Code requirement for bathroom fans is 50 cfm of intermittent bathroom exhaust to the outdoors (or 20 cfm of continuous exhaust), and if your fan is old it may not met these performance standards.

    The fan should be on a timer, separate from the light. That way, when people have done showering they can turn off the light and leave the fan running – this extra time ensures moist air gets exhausted from the space. The fan can also be connected to a humidity sensor so that it runs until humidity is brought down to a good level- make sure you select a humidistat suitable for damp areas. A nice quiet fan is the Panasonic Whispersense.

    There are mildew-resistant chemicals that can be added to paint but they apparently wear off after a while. It may be a better strategy to have surface finish which is water resistant, easy to wipe down and clean.

    The rest of the prevention regime involves occupant behavior – wiping up puddles of water, wringing out saturated towels, squeegy-ing shower walls down, etc.

    I think the most bang for the buck is having a quiet fan on a timer or tied to a humdistat to manage humidity levels in the bathroom.

    Sounds like you have some remodeling ahead of you!


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