By Carole Hawkins, [email protected]
When it comes to water seeping into a house, spawning mold and disintegrating structures, the enemy isn’t stucco. It isn’t clapboard, brick or for that matter, any type of cladding.
It’s putting building materials together in a way that doesn’t take Mother Nature into account.
Ron Young, a building science consultant and owner of the Jardy Group in Ponte Vedra, talked about water intrusion at the August meeting of the Clay Builders Council.
Building scientists forensically test homes, both before and after they have issues. They are the ones, Young said, who “find out why, why, why, why, why.”
When water gets into a home, most people look for flooding, broken pipes or leaky roofs. Rule out these, and the culprit becomes more mysterious.
Wicking
Just because surfaces are solid, that doesn’t mean water can’t get through.
All the materials used in building suck and move water through them via capillary action, known as wicking, Young said.
It’s the way water moves up a tree. Even concrete will wick water.
“They found out when they built Hoover Dam that water traveled through the concrete. They documented it up to 6 miles,” he said.
Air flow
The air in Florida outdoors is hot and moist. An air-conditioned home is cool and dry. Any air going from outdoors to indoors will bring water vapor in. Vapor that can condense on cool building materials can cause trouble.
For example in a normal environment, drywall will collect about a pint of water a week. Little enough that it easily dries out.
But a crack in an outside wall will often equal the exposure of a 1-inch diameter hole. Let moist air flow through it and the same drywall collects 14 pints per week.
Vapor diffusion
Even when a home has no cracks, a humid outdoors and dry indoors creates a pressure differential that wants to move water vapor from the moist environment to the dry one.
In the same way that water will wick through building materials, water vapor will diffuse through permeable building materials, absent a vapor barrier.
“Builders are spraying and rolling all this rubber on the outside, and saying ‘It’s not going to go in here. We’re not to have any leaks,’” Young said. “Well vapor diffusion will differ with you. It will come in.”
Dealing with water
When a home has a water problem, it needs to be addressed. “You can’t paint it, glue it, smudge it or caulk it away,” Young said.
Left alone, moisture in a wall system will travel to the fasteners holding it in place. Once the fasteners rust, the wall falls off.
Mold is also a consequence.
One misguided response is to “fix” mold by wiping the surface with bleach.
“All that does is take care of the top surface,” Young said. “You’ve done nothing to the roots, the mycelium of the mold.”
Still inside, the mycelium grows until it disintegrates the drywall.
Finding the source
When moisture gets in a home, fingers often point to the roofer, Young said. But nine times out of 10, the intrusion is coming through the walls. And overwhelmingly, it’s because some time-tested building techniques weren’t followed. They include using:
• A drainage plane — a layer of protective water resistant materiel, like house wrap.
• Drainage space — drain tile, gutters and sump pumps used for site and foundation drainage.
• Flashing — a strip of aluminum or other waterproof material that carries rain away from seams in the roof, windows, doors and decks.
• Weep holes — small openings in brick or masonry that allow water to drain from inside the structure.
They’re techniques Young remembers from years ago, when he used to lay brick with his grandpa. And, if he didn’t do them, he’d have “a brick upside the head.”
“Today we caulk and glue and use elastomeric paint — all to cover these things up,” Young said. “But what’s really happened is these four techniques have been lost.”