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Re: Header sizing for a kitchen remodel

From: info@builderswebsource.com
Category: Structural
Remote Name: 63.198.181.43
Date: 28 Nov 2002
Time: 12:34 AM

Comments

There is insufficient loading information in your description to say with certainty whether a 4x12 could adequately support a 14' clear span. One would need to know exactly how all loads are transferred to the beam, including the roof loads, as well as the ceiling loads. Without a detailed load drawing, a DF #2 grade 4x12 could support approximately a 200 PLF uniform load (live load plus dead load), given specific initial design assumptions. We believe your design load will be much higher than this figure, especially if the beam must support part of the roof. You may need a 6x12, 6x14, an LVL, or possibly even a steel beam if minimizing beam depth is a priority. Notching the beam in the center by 1.5" should be avoided. This is the point of maximum bending stress. Boring out the wood would simply reduces the effective design depth of the beam by about the same amount. You may be able to use a "pancake" box, which is only about 1/2" thick, which you can simply bolt directly to the bottom of the beam, or recess into the beam just slightly. Again, as you start taking material out of the beam, you weaken it. Given also the seismic considerations in Southern California, we recommend that you hire a licensed structural engineer to inspect your property and compute the loads for you. The engineer can also address other factors, such as the best way to transfer the loads to the outside columns, foundation, as well as connection details using a range of metal plates, brackets and saddles.

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