Much of the structural work described in the article "Expanding a Kitchen" (8/11) appears to be excessive or not effective. (It is also of interest that while plans by an "engineer" are noted, the name of the engineer is not reported.) First, the flitch beam does not appear to be necessary. Scaling from your floor plan (using a stair width of 7.5 feet), the beam span appears to be 14 feet 4 inches. For a "suburban Maryland" location, ground snow load is very likely either 20 or 25 psf, meaning roof snow load is then less than 20 psf - perhaps much less. So for design purposes, 20 psf is reasonable and conservative. The only other loads are from the attic space and short wall. My basic calculations show that, even for conservative deflection limits (L/480 live load and L/300 total) and long spans (total gable roof span of 30 feet and attic joist span of 15 feet), an 11 7/8-inch-by-3 1/2-inch LVL beam is more than adequate. The section drawing shows that a taller LVL beam would fit in the attic.
Second, the columns supporting each end of the beam are shown to bear on the end of a floor joist, directly over a steel girder. Reinforcing the entire length of one floor joist with a 7-inch steel plate is not necessary; solid wood blocking under the column is more than adequate.
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