|
Getting your Trinity Audio player ready...
|
| The Silicon Valley Association of Realtors (SILVAR) regularly shares local housing data, sales trends and other real estate-related topics. This week’s column provides tips on how to protect your home and its foundation from potential water damage from Sudarsan “Sonny” Vakul Srinivasan of MG Constructors & Engineers , who was the guest speaker at a recent association event. |
Homebuyers moving to California know to prepare for earthquakes, but many overlook a more everyday threat beneath their homes: clay soil.
Much of the Bay Area is built on soil rich in clay, and that can spell trouble during the rainy season. Dense and slow to drain, clay expands when wet and contracts when dry, creating movement that can shift or crack a home’s foundation.
Sudarsan “Sonny” Vakul Srinivasan, an engineering manager with Bay Area–based MG Constructors & Engineers, said homeowners here should start winter prep by checking two things: the structural integrity of their foundation and the effectiveness of their drainage system.
Clay is an “expansive soil,” behaving much like a kitchen sponge — swelling as it absorbs water and shrinking as it dries. That movement can push parts of a structure upward or allow them to settle unevenly, leading to cracking, Srinivasan explained.
“There’s always surface water that, when it rains and slopes toward the house, accumulates around the property or the foundation, and it can cause the soil to continue to move up and down,” he said.
On the Peninsula, much of Santa Clara and San Mateo counties sits on varying mixes of clay-rich soils. In cities along the Bay’s shoreline, including Foster City, East Palo Alto and Redwood Shores, soil profiles often include silty clay loam, sandy or gravelly loam and bay mud. Homes built on these softer soils, according to experts, frequently show signs of stress, such as horizontal cracking.
During winter, managing water is critical for your foundation, Srinivasan said.
It’s important to maintain correct grading around your home for proper drainage, keep gutters clear, and seal foundation cracks. In drier winters, homeowners may also need to keep the soil slightly moist to avoid dramatic shrink–swell cycles that can worsen foundation movement.
Persistent dampness
A home’s foundation isn’t the only thing that can be impacted during wet weather, according to Srinivasan.
Moisture issues bring their own set of problems. Persistent dampness can lead to mold, attract pests, reduce indoor air quality and accelerate metal corrosion — especially in homes with crawl spaces.
Srinivasan said he’s found severely corroded screw jacks beneath homes.
“I would be able to swing the jack like a pendulum,” he said. “That’s not something you want to see. All of these issues are stemming from high moisture levels or humidity levels, or a drainage problem inside the crawl space or the basement.”
Drainage problems often develop slowly but can cause noticeable structural movement in as little as nine months. Staying ahead of them is key.
He recommends watching for early warning signs: musty odors, standing water after rain, water stains on foundation walls or framing, soil erosion near the house or garden materials — such as planters, mulch or wood chips — stacked against the foundation.
“It could have rained for a couple of days, but these chips might still be able to hold onto that moisture (after the rain),” he said.
Preventative measures
Srinivasan offered these guidelines for preventing moisture-related damage:
Clear your gutters
Clogged gutters can overflow and dump water near — or even under — your foundation. Clean them regularly or consider gutter guards.
Ensure positive drainage
Soil and hardscape should slope away from your home. Downspouts should have splash blocks that move water well away from the foundation.
Service your sump pump
If you have an exterior sump pump, get it checked annually to ensure it works and its one-way valve is functioning.
Install proper drainage systems
A sump pump alone isn’t enough for a crawl space; it should be paired with French drains or footing drains that collect and route water to the pump.
Control humidity
Mold begins forming when humidity stays above about 60%. If you use a dehumidifier, pair it with a sealed vapor barrier so moisture isn’t continuously pulled from the soil.
“You must first stop the moisture supply,” Srinivasan said, “and then remove the remaining moisture from the crawl space to the outside.”
Silicon Valley Association of Realtors (SILVAR) is a professional trade organization representing 5,000 Realtors and affiliate members engaged in the real estate business on the Peninsula and in the South Bay. SILVAR promotes the highest ethical standards of real estate practice, serves as an advocate for homeownership and homeowners, and represents the interests of property owners in Silicon Valley.
The term Realtor is a registered collective membership mark which identifies a real estate professional who is a member of the National Association of Realtors and who subscribes to its strict Code of Ethics.
Real Estate Editor Linda Taaffe contributed to this article.
