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BRISBANE — Host, Sarah Rutan: To ensure earthquake safety, you’ll want to know the condition of your home’s foundation and whether it needs to be repaired or reinforced. Today we’re in Brisbane with Diamond Certified Expert Contributor Christopher Wells of Christopher Wells Construction to learn more.
Diamond Certified Expert Contributor, Christopher Wells: Hi. My tip is regarding concrete foundations in the San Francisco and North San Mateo County area. Most of the houses that I work on are in those areas, and they mostly have what we call perimeter foundations as opposed to a slab foundation.
Houses that were built in the early part of this – of the previous century – like the 1920’s and thirties – may have foundations where the builder used local materials, which was not a good thing. If they use local sand, it would have impurities in it, and that leads towards degradation of the concrete. They also probably didn’t use enough portland cement, which was very expensive in those days.
You can identify that if you go down into your basement, and take a hammer or a screw driver to your foundation, and try to scrape off pieces of your foundation. If you’re successful, that means you should probably call an engineer and have him look at the foundation, because you may need repair.
Another problem that we often see is differential settlement of the foundations. Because, in the old days, they didn’t build foundations with as large a footing as we use nowadays. So, the foundation components will sort of knife down through the ground. What you can do to look for that is keep an eye on the interior of your house for diagonal cracks in walls above doors and windows. And, if you find that a door or a window that has been functioning okay in the past suddenly gets jammed, shut, or won’t open, then you may have a settlement problem. And, you should also call an engineer for that.
Host, Sarah Rutan: To learn more from local top-rated companies, visit our Diamond Certified Expert Reports at experts.diamondcertified.org.