Smell something musty? See that white, black or orange fuzzy stuff? Are your walls working up a sweat?

You home is groaning about mold moving in.

Waterproofing is an option, but perhaps a last resort.

This winter's heavy snows will melt, likely to be followed by periods of flooding, spring rains and still more moisture -- mold's friend and your enemy.

A fungus, mold and its wind-borne spores are ubiquitous in nature. Relatively harmless to most people molds can cause hay fever-like allergic reactions in some people and more severe respiratory, pulmonary and neurological health effects in fewer people.

Mold is more immediately problematic for the structural integrity of a building because molds are nature's decomposers. They survive by releasing enzymes to help them absorb and digest nutrients (cellulose, protein, and fats) from host materials -- any living or dead organic matter, including many home building materials.

As molds feed, materials deteriorate and weaken.

Hungry molds thrive in high humidity, but they really begin to chow down when moisture comes in contact with a food source.

Keep in mind, mold isn't the real problem, but more of a symptom of some underlying condition that allows water or moisture intrusion. Within 48 hours of some unaddressed water event, say melting snow, a rainstorm or plumbing leak and the table is set for molds to pig out.

Akron, Ohio's B-Dry Waterproofing offers some tell-tale signs mold is munching at your home, likely because of that persistent moisture problem.

• A musty odor coming from your basement means moisture paid a visit and refuses to go.

• A white, chalky efflorescence, or black or orange fuzzy splotch are other indications moisture is going nowhere fast.

• Sweaty walls also indicate trapped moisture is, well, hanging around. Experts advise before you consider waterproofing, make some inspections and take a host of preventive measures and moisture abatement steps beginning with proper drainage, proper cross ventilation and perhaps a less costly French drain, which will direct water away from your home.

As a backup or adjunct to drainage measures, get a professional to install a sump pump below grade in your basement or crawl space to quickly remove any standing water.

"In 98 out of 100 cases, the French drain solves the problem. It captures the water and diverts it before it gets to the house. For less than $500, that's the first thing I would do. Other systems want to collect water inside the house," said Cincinnati's Tim Carter, master contractor and publisher of AskTheBuilder.com.

Waterproofing is best installed on homes under construction because a retrofit, professionally completed, can demand excavation to the foundation.

"There are products that do work after the house is complete but it's miserable. You have to move the landscaping, dig out, clean off the foundation, let the concrete dry and then bring in the waterproofing. It's just brutal. Like death on a stick," Carter says.

Carter also says don't confuse waterproofing with damp proofing, which is a building code requirement to reduce, but not prevent moisture intrusion. Also, building codes for damp proofing and vapor barriers can vary from one jurisdiction to another.

Waterproofing generally means applying an impermeable barrier to the exterior, say a 1/8 inch thick coating of hot asphalt and rubber or some other material topped off with insulating panels to protect the coating during back fill and to act as a drainage plane.

Some professionals say interior waterproofing applications can do the job without the hassle of digging out, especially when the problem is smaller with more manageable dampness or moisture conditions, rather than heavier water intrusion. Consumer Reports also found useful products during its latest survey a few years ago.

But Carter says shoddy work on large jobs could allow hydrostatic pressure to collect and build from the outside and waterproofing is best when it prevents water and moisture from entering.

"If the hydrostatic pressure gets great enough, if it's greater than the strength of the compound you put on, the leak is there again. Put the liner on the outside, not the inside," says Carter.

However, even in severe conditions, say during a flood, sealing your home from the outside leaves it without compensating pressure from the inside and that could make an older home more susceptible to collapse.

An engineer's certification may be necessary to determine that the walls you waterproof from the outside won't buckle under pressure.

Obviously, waterproofing isn't a do-it-yourself job.

Hire a licensed professional with documented experience in the process.

"Do it right the first time," Carter says.

Andrew Rehner, a waterproofing and structural repair contractor and principal with Basement Guys of Toledo, OH, says for existing homes, each is different and requires a full assessment to determine what's causing the moisture intrusion and how to stop it.

Some additions and floor plans render external waterproofing efforts cost prohibitive.

"You can't tear down a garage to waterproof and you can't jus waterproof just part of the outside. That will only get you part of a solution and it could cause problems somewhere else," says Rehner also a spokesman for the National Association of Waterproofing and Structural Repair Contractors, which offers additional guidance.

"It really depends on the situation and it has to be assessed. Go to the association's website, find someone in your area who is licensed, has a national certification," and compare the recent and past work of several professionals, he added.

Published: January 18, 2007

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Broderick Perkins parlayed a career in old-school journalism into a contemporary digital news service that really hits home. The award-winning consumer journalist, originally from Wilmington, DE, is founder, publisher and executive editor of the bootstrap DeadlineNews Group, a Silicon Valley-based editorial content and consulting service specializing in residential real estate, consumer news and related editorial consulting services. The DeadlineNews Group includes the website, DeadlineNews.com, offering real estate editorial content and consulting services, and its back shop, the Deadline Newsroom, an open house on news that really hits home. Perkins obtained his formal journalism education from University of Delaware and a journalism boot camp, the Institute of Journalism Education at the University of California-Berkeley. He went on to 20 years of service as a daily newspaper journalist at the Wilmington, DE News Journal and San Jose, CA Mercury News. Perkins covered housing on the San Jose Mercury News reporting team which earned a General News Reporting Pulitzer Prize in 1989 for coverage of the Loma Prieta earthquake. He has also produced real estate, consumer and small business content for the Wall Street Journal, Los Angeles Times, RealtyTimes.com, Nolo.com, Better Homes and Gardens, the National Association of Realtors, Homestore/Move and Intuit/Quicken among more than three dozen publications. In addition to managing the DeadlineNews Group, Perkins most recently served as chief editorial consultant for Nolo's Essential Guide To Buying Your First Home, Nolo, and writes real estate television scripts for RealtyTimes.com.