Earthquake Strapping your home can save you money!

Earthquake Strapping your home can save you money!

Earthquake Strapping your home can save you money!

Cornerstone Builders can help your home qualify for Earthquake Insurance! Do you have earthquake insurance on your home? Is your home even insurable for earthquake protection? Do you know what Earthquake Strapping is and how it is done?

Wood homes get better rates than brick buildings because wood tends to withstand quake stresses better. The Insurance Information Institute notes that premiums are also based on the nature of the soil and your house’s proximity to recognized fault lines.

In addition, areas are graded on a scale of 1 to 5 for likelihood of quakes, and this is reflected in earthquake insurance rates. Because earthquake insurance is a type of catastrophic coverage, most policies carry a high deductible — anywhere from 2% to 20% of the replacement cost of the structure. For instance, if the cost to rebuild your house after a quake is $100,000 and your policy has a 2% deductible, you would be responsible for the first $2,000.

Single or two story wood-frame domestic structures built on a perimeter or slab foundation are relatively safe in an earthquake, but in many structures built before 1950 the sill plate that sits between the concrete foundation and the floor diaphragm (perimeter foundation) or studwall (slab foundation) may not be sufficiently bolted in. Additionally, older attachments (without substantial corrosion-proofing) may have corroded to a point of weakness. A sideways shock can slide the building entirely off of the foundations or slab.
Often such buildings, especially if constructed on a moderate slope, are erected on a platform connected to a perimeter foundation through low stud-walls called “cripple wall” orpin-up. This low wall structure itself may fail in shear or in its connections to itself at the corners, leading to the building moving diagonally and collapsing the low walls. The likelihood of failure of the pin-up can be reduced by ensuring that the corners are well reinforced in shear and that the shear panels are well connected to each other through the corner posts. This requires structural grade sheet plywood, often treated for rot resistance. This grade of plywood is made without interior unfilled knots and with more, thinner layers than common plywood. New buildings designed to resist earthquakes will typically use OSB (oriented strand board) or plywood, sometimes with metal joins between panels, and with a well attached exterior siding covering to enhance its performance.

Earthquake strapping can keep your home on it’s foundation during an upcoming earthquake, and may save your home from a complete restoration. There are many different ways to provide seismic updating to your older or newer home. Some homes will receive plates attaching the foundation to the “green plate”, while others will utilize larger straps tieing floor joists or wall studs to the foundation. Have you heard the satement “United we stand, Divided we fall”? Earthquake strapping creates shear walls within the structure to hold larger sections of your home together and prevent them from individually failing. We want our homes to act as a system of team all working towards the same goal: stick together!

Cornerstone Builders, Inc. is a local Beaverton Remodeling Contractor providing seismic upgrading to homes of any age. Please visit us at or call503.671.9538

Allen Tankersley