This Mold House redux: One word: plastics

NolaVie editor Renee Peck wrote This Mold House for The Times-Picayune for four years after Hurricane Katrina. She is reposting a number of her favorite columns in conjunction with the 10th anniversary of the storm. This article originally was published in The Times-Picayune InsideOut section on Jan. 21, 2006.

Stewart drags people in off the street to show them our new insulation.

“Touch it,” he’ll say. “Is that not cool?”

We went with spray-foam insulation in the newly gutted walls of our East Lakeshore house. A little bit of knowledge is a dangerous thing, and I had learned just enough from an interview with Claudette Reichel to be menacing when it came time to talk padding.

She’s in charge of Louisiana House, a prototype residence being built by the Louisiana State University Agricultural Center in Baton Rouge. It showcases construction methods best suited to our climate — materials and techniques that combat termites, moisture, high winds, insects, flooding. Check it out at www.louisianahouse.org.

On a walk through the half-completed building in November, I was salivating over hurricane straps and walls made of insulating concrete forms.

“We need an exterior air flow retarder system,” I told Stewart.

“Sounds expensive,” he replied.

When mold ate through our Sheetrock, it didn’t stop. Whole colonies munched on into the sheathing between the studs and the outer brick walls. We had to remove the mottled house wrap, our flood adjuster said, or he wouldn’t approve our claim.

So there we were with studs and brick and no sheathing between, like a dowager with a see-through silk skirt and no slip.

“An exterior air flow retarder system,” I explained to my husband, who thinks R value refers to a toy store, “is a method of combining materials to create a tight building envelope with no air or water seepage. Right now, our house leaks both like the Titanic.”

“Sounds expensive,” he said.

I talked to anyone who would offer an opinion on how to rewrap and reinsulate my house — including the hapless Tyvek salesman seated next to me on a Southwest flight to Houston. One contractor told me I’d have to take down the exterior bricks to replace the house wrap behind them.

Then one day the genial carpenter working on the house next door handed me a card and a brochure.

“I thought of you immediately when I saw this,” he said, proving that my home’s semi-nakedness had become something of a communal cause.

“This” was Energy and Comfort Solutions, a Madisonville company dedicated to “building thermal envelope systems.”

These guys were already talking my language.

The company’s Robert Lazaro came over and talked to my contractor, Shane Kitchens, and soon the two were deep into a conversation about how to clothe my outer walls.

Kitchens filled the gaps behind and between studs with waterproof 40-weight oil cloth, overlapping and stapling each piece so the moisture-proof exterior would keep out the damp, the cold and perhaps even termites.

Then Lazaro pumped spray-on polyurethane into all the spaces. It goes on like shaving cream and hardens to a Styrofoam consistency.

“Wow,” said Stewart, who kept punching holes with his finger. “It’s like, I don’t know, package peanuts all fused together.”

He didn’t even mention the expense.

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A FEW WORDS OF EXPLANATION

WHAT IS IT:

— Spray-on foam insulation is made of polyurethane, which is pumped in a liquid form through pressurized nozzles and sprayed into wall and ceiling cavities. Within less than 20 seconds, it expands and solidifies into a cellular plastic that contains millions of tiny air pockets and fills every nook and cranny.

This “open-cell” spray foam insulation is well suited to our hot, humid climate, says Paul LaGrange, a certified energy consultant for Cleco. A closed-cell form of foam insulation, used elsewhere in the country, is much less desirable. “We really want our air to dry from the outside in,” explains LaGrange. “Closed-cell foam insulation is a vapor barrier, which means that it will trap moisture in the wood, which can cause rot.”

ADVANTAGES

— Foam insulation forms a thermal envelope, meaning that it keeps out hot air in the summer and cold air in the winter, adding to a home’s energy efficiency. “It’s a true air barrier,” says LaGrange. “Fiberglass and cellulose are not air barriers. As air travels through them, their performance decreases — especially since our air is filled with moisture.”

— Open-cell foam insulation also insulates for sound; placing it around water pipes can drastically reduce water noises in the wall.

DISADVANTAGES

— Putting in foam insulation is not a do-it-yourself project; it takes professional equipment and installation.

— It’s more expensive than batting insulation; online sources declare it 20 percent higher in cost, but for us it doubled the price — from about $2,000 for fiberglass batting to about $4,000 for spray foam.

“It’s a premium product, but there is a trading of resources,” says LaGrange. “You can buy smaller air and heating units for the house, and it also will save on energy costs.”