Q: My problem concerns a musty odor that I noticed almost immediately upon moving into our newly built home.  We’ve been here about six months and the problem doesn’t seem to be subsiding.  In certain rooms of the house I notice a very musty odor.  Sometimes there is no odor other times it is very strong.  The house is in the Dallas area and is built on a slab foundation.  I know it was an unusually wet winter and spring when the home was being built.

I guess my question is can it be a construction related problem that will eventually go away?  If it is mold related, how do I tell the builder (Centex Home with a two-year warranty) that I need the home throroughly inspected and should I rely on them to do this?

A: The odors that some people refer to as musty, could be reported as mold-like by someone entirely different.  Simply put, when you smell musty or mold-like odors in a space, that is a good indication that mold is present.  What you are smelling is referred to as microbial volatile organic compounds (MVOCs).  These are created in the metabolic process that mold colonies go through during their lifecycle.

It is entirely possible that what you are smelling indicates the presence of a mold colony located inside the walls, underneath a base plate, on top of a ceiling area or even inside the air conditioning unit or air duct systems.  These molds may be growing because they’ve found an active source of moisture somewhere in your home.  This source could be from a failed flashing, high water leaking onto slabs, roof leaks in the attic or even a poorly operating air conditioning unit.  Even the best of homes can leak during unusually wet periods – which is what Dallas has been experiencing this year.

If the odor is caused by construction materials that became wet during construction, as they dry out the molds may go dormant and the odor cease.  Unfortunately, elevated levels of relative humidity or even several days of rain may provide enough moisture for the molds to wake up and start producing the odor all over again.

Communicating this kind of problem with the builder early and often until it’s resolved is probably your best recourse at this time. You might also consider hiring a home inspector with experience in identifying these kinds of issues to look at the home. The right inspector may even take the time to explain where the problem is occurring, where moisture may be coming from and how it needs to be fixed.  That would allow you to become an educated consumer who should find it much easier to talk with the builder’s representatives.

Travis West is the president of Building Air Quality Inc., a Houston-based indoor air quality consulting firm. He can be reached at twest@baq1.com , or toll-free at 866-367-1177 or visit http://www.baq1.com/

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If you have a question for a mold expert, please send it to Brett Lyon, senior editor of construction.com at brett_lyon@mcgraw-hill.com.