Our neighbors thought we were CRAZY!
by Jennifer Eggers, Project Engineer - Degenkolb Portland Office
It all started six years ago when my husband and I moved from California to Oregon and decided to buy a house that was built in 1906. Spruced up on the interior, and needing a “little” TLC when it came to the foundation, we were ecstatic about our very first home purchase!
You might think the foundation would/should have been our first major home improvement project. It wasn’t. Life happened and I became pregnant with our first son, Will. Our tiny 1906 house with only 2 bedrooms needed a place for grandparents to sleep when they came to visit. So, what did we do? Tore down our detached garage (that was practically falling over anyway) and built a detached in-law unit, which is basically a studio apartment – in 4 MONTHS! The exceptional schedule was the result of a Degenkolb team which included Devon Lumbard and Jim Newell (who work for food if you ask nicely).
Since then, the most notable project made all of our neighbors think we were crazy. We jacked up our house and completely replaced the foundation. What was the point of all this? Our wood framed house was originally constructed with floor joists running east-west that span between three 6x6 wood beams that run north-south. These main wood beams are supported on 8” square and 12” tall brick piers every eight feet or so along their length. At some point, someone came in and placed new wood columns on small precast concrete bases in between the brick piers, leaving us with a short column every four feet or so.
Basically, we were left with a house on tiny stilts, which is not good in an earthquake. Our concern was if we had an earthquake in Portland, our house would shift over and drop about 12 inches - which was the depth of our crawlspace. We weren’t too excited about this idea so we wanted to do something about it. We also didn’t want to spend a ton of money, so we tackled it ourselves and came up with an inexpensive/easy fix. We dug a trench along the side of our house down to the bottom of the foundation, jacked up one side of our house, removed the existing foundation and replaced it with a concrete grade beam. We installed blocking between the floor joists that sit on top of the 6x6 beam, attached that blocking to the first floor diaphragm and anchored the 6x6 beam down to our new concrete grade beam. The exterior straight sheathing bringing load from the second floor diaphragm will be connected directly to the 6x6 beam. Voila! You have a load path for the seismic forces.
This summer, we did a trial run of our retrofit plan on one side of our house. Two weekends later, the structural portion was done! With the help of a few friends/co-workers (Thanks Seth Thomas!...again…just offer food and ask nicely), a few babysitters and even the kids - everything went smoothly and we were able to meet our two weekend timeline. This was a family affair. Jack (my youngest at 17 months) was a great inspector. He really wanted to help by handing you screws and A35s. Will (my oldest at 4 years) did a great job threading the nuts on the anchor bolts. I have never seen him sit as still as he did the morning of the concrete pour watching the small-batch concrete truck mix the concrete. On the way to school that day he asked me if we could buy a concrete mixer truck and how it would be so cool and fast! As soon as we got home that day (without prompting or reminding) he ran around to see if the concrete was dry. He said it was good and strong. He is excited about next summer’s project of completing the rest of the foundation retrofit!