Volume 46, Issue 1 - January/February 2007

The Blame Game
Building Professionals Points Fingers, 
Search for Solutions to Mold in Lumber

by Samantha Carpenter

Juries have awarded millions of dollars in mold cases. Plaintiffs have received awards as high as $1.04 million to $32 million. With mold-related lawsuits on the rise, lumber dealers, builders and framing contractors need to properly store their lumber, so they aren’t accused of being part of the mold problem. 

According to information from the Southern Pine Council of Kenner, La., “Molds are fungi; ubiquitous organisms that (under proper conditions) can grow on organic matter. Surface molds, which can come from a variety of sources including airborne spores, feed off the sugars and starches readily available in wood.”

It’s not surprising to find mold on lumber in lumberyards or jobsites, but then the question becomes, “Who is to blame?” 

Advice for Lumberyards
Richard Kleiner, director for treated markets, Southern Pine Council, advises dealers to order lumber that is paper wrapped to protect it from the elements and to cover lumber during the transportation process, on the yard and at the jobsite.

“At the dealer yard, ideally, we’d like to see the lumber stored under roof when possible,” Kleiner says. He clarifies that under roof means some sort of metal roof—somewhere the lumber isn’t going to get direct moisture or direct sunlight.

Susan Raterman, a certified industrial hygienist and president of The Raterman Group Ltd. of Chicago, gives similar advice.

“There are some simple steps that can be taken to prevent mold growth on lumber during storage and construction, starting at the lumberyard. Wood and wood products should be stored under cover in a dry location. Product should be inspected before it leaves the yard to assure that moldy lumber is not being sent to the customer. To reduce claims, prudent lumber dealers have a program of mold inspection and cleaning prior to delivery of lumber,” Raterman says.

“We suggest dealers and distributors use moisture meters to spot-check their product when it’s delivered. It’s the option of the dealer to return the lumber (speaking of Southern yellow pine) if it is over 19 percent moisture content,” Kleiner says.

When the lumber is delivered to the jobsite, Kleiner says the lumber pack should be raised above ground four inches, so the lumber isn’t in contact with moist earth. He also says it should be protected with some kind of material like a tarp, but something that is breathable.

The Status Quo
Some lumberyards, dealers and distributors do store their lumber as Kleiner advises. Dale Byrd, store manager for Thomas Lumber of Winter Park, Fla., says his company keeps its lumber inside.

“Usually the only time we get mold is on lumber returned from the jobsite for credit.”

To help keep its lumber mold-free, Pete Vrendenburgh, president of Vrendenburgh Lumber Co. of Beardstown, Ill., says his company lathes its lumber only five layers deep.

Donald Kearney, owner of the building contractor company, Topflight Services of Parsippany, N.J., says he does two things.

“One is to store as little as possible. Inventory is lost cash flow or deferred cash flow; both of which are detrimental to profitability,” he says. “The second is to store whatever lumber I have in a climate-controlled area. I use a basement area which is heated (to about 60 degrees) in the winter and dehumidified in the summer, so mold is not a problem.”

John Halleland is president of Story City Building Products of Story City, Iowa. His company stores most of its lumber inside or on full pallets that are paper wrapped and under a roof overhang.

He says the mill from which he buys his lumber wraps it before shipping, and covering his lumber adds about $7 per 1,000 board feet to the cost of the lumber.

“I think the most important thing is to buy the lumber dried to 19 percent or less and to keep it protected from the weather,” says Halleland. “Very humid locations make mold a much more serious problem than what we have in the Midwest. Buying lumber ‘green’ or not dried is an invitation for problems.”

Panel Concepts Inc. in Mio, Mich., also stores its lumber inside or covered outside. President John Gascho says employees check the moisture content of lumber upon arrival and make sure it is at 10 to 15 percent. Sometimes the company will dry the lumber when it arrives from the sawmills.

Treating the Lumber

Some lumberyards, dealers and distributors not only cover their lumber, but they also treat their lumber with mold-resistant preventatives.

Santosh Patel, managing director of Stonehenge Building Group, says, “Although we try and cover our lumber in the best fashion we can, there are many factors related to the weather that we cannot control. We like to treat our lumber with a boric treatment after we are under roof.”

Patel also says that covering the lumber with a plastic tarp only takes a few minutes and the cost is minimal, unless “you are continuously covering your lumber—then it’s not worth it.”

There are many products on the market that are available.

Scott Hoffman is business manager for interior protection systems for Arch Wood Protection. 

“Arch Wood’s FrameGuard covers not just your studs for framing a wall, but also your panel goods and oriented strand board (OSB) … You can basically take a standard house framing package with any material and apply the FrameGuard coating to that and get it to the jobsite. It allows us to process the material quickly,” he says. 

He explains that FrameGuard is a coating containing a blend of anti-mold chemicals and borate technology that was developed specifically to address mold issues on wood products going into residential construction, although it also carries over to multi-family and commercial construction.

Hoffman says when the treated material arrives at the jobsite, it is protected from the start.

According to Eric Green, president of Siamons International, Concrobium has been available in the United States for use on lumber for about six months. The product is designed for mold prevention as well as remediation.

“It’s unique because it’s entirely natural—it’s an all natural mold-resistant and mold-eliminating product,” he says. “When you spray mold with our product on lumber, it physically encapsulates the mold spores, and the film dries … into an antimicrobial shield that actually crushes the spores and contains them. While the stain may not be eliminated, that mold is dead and won’t grow, and the lumber won’t get moldy again.”

Yes, We’ve Seen It
Even with numerous products available designed to prevent mold on lumber—and more importantly, growing awareness that mold could cause a problem for the builder, or the homeowner, down the road—it is still not unusual to see dark spots growing on lumber sitting on a jobsite or framing a house. 

“In my experience it is not uncommon to find some mold growth or dark staining on new lumber and wood products in the majority of construction sites,” says Raterman. “I have been involved in some projects where a homebuyer will walk the construction site, discover moldy lumber and refuse to move forward with the purchase until the wood is replaced or the mold is remediated. In other cases the used moldy lumber has resulted in seven-figure remediation and rebuilding costs. Responsibility for remedial action often falls on the lumber dealer.”

“My company has no tolerance for mold,” says Kenneth Kellams, purchasing manager for FBI Buildings Inc. of Remington, Ind. “I have a plan and policy in place with my supply chain, truss plant and yard. Mold is rejected immediately upon inspection of every unit that is unloaded. It is removed from my yard in two weeks, and this is part of my vendor agreement.”

James Price, president and owner of Price Construction in Beaverdam, Va., says that he sees moldy lumber all the time.

“If you have wood that’s moldy, visibly moldy that is, then, yes, at some point you let it dry out as much as you can, and once you’re ‘under roof,’ you spray it with bleach in a garden sprayer and kill it, then let it dry completely,” he says.

A Perfect World
In a perfect world, all lumberyards would check lumber for moisture content when delivered, they would cover their lumber in their yards, they would cover their lumber during delivery and at the jobsite, and builders and contractors would keep the lumber covered and out of the elements.

“What you have to remember is—you’re not shipping things to a grocery store, in a conditioned vehicle and into a perfectly conditioned space,” says Price. “Sure, you get lumber delivered to a jobsite that’s wet, or it gets wet once it’s on the jobsite, but what are you going to do? Tell builders ‘You can’t use this wood until the ground moisture level is below blank and the humidity levels are below blank and the wood has completely dried out?’ You just can’t hold up the construction process like that.”

Kleiner concurs with Price. “You should use the lumber and enclose the structure as quickly as possible to minimize exposure. There is a phenomenon called blue stain, which some consumers think is mold [but isn’t]. Both mold and blue stain affect the color of wood, but neither have an affect on the strength or durability of the lumber,” he says.
Raterman says the best advice she can offer lumber dealers to reduce their exposure to liabilities surrounding mold is to develop a written mold and moisture control plan, train their staff and put the plan into action.

“The plan should address proper storage of wood products, quality control inspection procedures, how to detect mold, how to remove mold, when to get expert advice and what to do when moldy lumber is mistakenly distributed to customers,” she says. “Secondly, educate your partners—the builders. Not all mold problems in a building are caused by moldy lumber and the challenge of controlling moisture does not begin or end with just using dry materials.” 

How to Store Lumber Outside
Whether at the mill, distribution center or retail outlet, air flow and protection from wetting are key factors in the lumberyard layout, according to the Western Wood Products Association’s Online Technical Guide (www.wwpa.org/techguide). A large volume of air should circulate through the yard freely to help evaporate and move moisture from the lumber. Lumber dealers should make certain the yard is open, with no trees or buildings blocking the air flow. Weeds and other vegetation should be removed because they can harbor mold spores.
Good water drainage is equally important. Standing water can add to the yard’s humidity, which increases the possibility of mold and stain. Paved surfaces provide a barrier to moisture vapor movement out of the soil. Proper site grading can reduce the chance of water pooling in the lumber yard and may lead to faster evaporation of surface water.

Providing air space under lumber piles allows cool moist air to move downward and away from the piles. The supporting stringers should be sturdy, level and high enough to allow air circulation. 

In more arid climates such as the Southwest, where drying may occur quickly, lumber piles can be oriented so prevailing winds travel perpendicular to the main alleys to slow drying of rows further downwind.

When lumber is placed on stickers, the stickers should be aligned vertically with one another and with the foundation stringers. Otherwise, sagging can occur, causing the lumber to bow or have a “belly.” Also, avoid stacking piles to excessive heights because it can add weight that crushes the lumber at the bearing points and causes the wood to kink. Some stickers should be placed as near the ends as possible to reduce checking and splitting.

What is Blue Stain?
Blue stain is not mold. It’s a sap stain and is a bluish or grayish black discoloration of the sapwood caused by the growth of certain dark-colored fungi on the surface and interior of the wood, according to information from the Southern Pine Council. Blue stain can occur under the same conditions that favor the growth of other fungi.

With some molds and the lesser fungus stains, there is no clear-cut way to differentiate between the two. In general, the difference between mold and stain is made primarily on the basis of the depth of discoloration. Unlike mold fungus, typical sap stain or blue stain fungus penetrates deeply into the sapwood and cannot be removed by surfacing or chemical cleaners.

Under Southern Pine Inspection Bureau grading rules, stain and discoloration due to exposure to the elements, are characteristics allowed on Southern Pine lumber. Stain is an appearance characteristic only and is allowed in varying degrees in all lumber grades. The Bureau says it does not affect the lumber strength or utility, nor does it pose any health risk.


Samantha Carpenter is editor of Shelter magazine.

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