Mold in homes is not surprising, but it’s also not desirable, particular if there’s a lot of it.

A few years back, my husband and I went to the Monterey Peninsula for a couple of days to celebrate our 25th wedding anniversary.  We had a wonderful time there, but would not return to the hotel where we stayed this time.  The worst issue was the mold in the bedroom along the wall and baseboard.  I brought it to the hotel’s attention and it was “cleaned”, but I think the issue is far from solved.

Mold and Mildew

Mold is often called mildew, and is seen perhaps most often in bathrooms around the shower, tub, or window.  Below is an image of of this substance (tested, verified) in a garage on an outside wall.


Mold sample on garage wall

First, I should state that mold is naturally occurring and it is not possible to completely eliminate the spores from your home.  The question is whether or not what is inside the house is the same kind and density as the mold outdoors, or whether something unusual is harbored indoors.

Mildew needs moisture and the right, mild temperatures to thrive – eliminate the source of water and it will go dormant.  Please note that it will not die when the moisture is eliminated – it just goes into a sleepy state.  If water is later reintroduced, the spores will spring back to life.

In my experience, the most common place to find mold in the San Jose area tends to be in bathrooms, particularly around older aluminum windows (which tend to be very cold and collect condensation). Mold on these window frames is easily cleaned by using a solution of water and bleach, and it can be prevented by better ventilation and heat, which allows the window frames to dry out. Likewise it’s very easy for it to grow in showers and tub areas due to the high amount of water present.  That water needs to be able to evaporate, otherwise you’re inviting it to take hold.

Step 1: find the source of the mold

Find growths on sheetrock, wood or carpeting?  First you must discover the source of the moisture.  Most likely, there’s a leak somewhere, either a plumbing leak or around a door, window, roof or flashing.

In the case of our hotel room, the corner where I discovered the nasty stuff backs to a bathroom on one side and another hotel room on the other (which probably has the same floor plan, so probably another bathroom). In fact, directly behind this mess is the bathtub and shower.

The maintenance man who came to see the black substance (and other issues) thought that the problem was a result of not enough caulking around the tub.  That’s possible.  (It’s also possible that the source of water is a plumbing leak.) Something to note, though: if it is from a lack of caulking, the moisture still had to go all the way through the wall and down to the floor and baseboard. What is the issue there? It’s possible that the entire wall had moisture damage, mold, fungus or dry rot.  Cleaning the outside of the wall with bleach is a tidy short term solution, but that is like covering the tip of the iceberg.  There’s a very high probability that a lot more of the stuff is lingering between the walls.

So too with mold in the home you wish to buy or sell.  First you must find the source of the problem – the leak or place where water has gotten to be where it doesn’t belong. (Sometimes the problem is not a leak per se, but rather construction issues which cause humidity to be held in the home.  This is a bigger issue in more humid climates than ours.)  Then you can repair the leak or replace whatever is faulty and next remediate the problem.

Back in September of 2001 (during 9-11, actually), I was at a real estate convention and symposium in Seattle. I sat in on a 3 hour class on mold, if you can imagine!  We saw horrific photos of mildew and mold in walls but also in mattresses, carpet padding and all kinds of places where you would not expect it.  In each case, there was a water culprit somewhere.

In one memorable case, a leak around the chimney at the roofline (flashing) allowed water to travel down the outside of the chimney all the way to the basement, where it hit sheet rock and it took over the entire wall.

Sometimes the only solution, after stopping the source of the moisture, is to remove and replace the sheet rock or other materials.

What about that hotel room?  I have to wonder how often the wall and baseboard have been cleaned, only to have the issue resurface later because the wall is full of mold.  If you look carefully at the photo, you will see that the walls’ texturing isn’t quite right. If the sheet rock got really damp, it could swell up.  If it were in my home, I would remove the sheet rock and see what was happening between the walls (or have it professionally done).

Not all molds are equally hazardous to us

As you probably know, not all mold types are equally harmful to humans.  If you run into it in your home, you may want to get it tested to see how serious it is.  There are companies which can do that for you (testing the surface with a swab or taking an air sample or carpet sample).  Just remember that it is normal to have some of it in the home – if you have a comparison done of the air outside your home, you will find mold there too.

Home sellers: if you have mold in your home, it is very important to both fix the problem and to disclose that you’ve had a problem with it in the past (even if fixed).  The number one reason for real estate lawsuits is non-disclosure by sellers to buyers, and if you don’t disclose or “under disclose” and the problem resurfaces, you are going to be looking at a very expensive problem.

Home buyers: if you see mold in the home you wish to buy, do some investigating and ask your home inspector whether further testing is warranted and reasonable.  Water is often more damaging to homes than termites, so pay close attention to any hints of water intrusion and leaks.

Getting a home tested by professionals for various types and concentration can be expensive, but it may also provide you with very valuable information and possibly also peace of mind.  Contact me if you would like the name and number of a company that can do that for you in Santa Clara County and nearby parts of the San Francisco Bay Area.

For more information on mold, moisture and the home, please see these links from the EPA:

Mold and Your Home

Mold and Health

Mold Cleanup in Your Home