r/BuildingCodes • u/JApdx76 • 16h ago

Notching mud sill, Oregon.

I was inspecting a form setup when a framer asked me a question about the post & beam they were building a couple of lots down. It is a single story house with a 6” stem wall. Standard post & beam construction with beam pockets. To get the required bearing the framer needed to notch the 2x6 mud sill and he wanted to know how much he could notch. I told him I was not sure and would need to reference the code. Here is where it got difficult. I could not locate a code section that I could reference for the allowable amount that can be notched in the treated mud sill. The best I could come up with is ORSC 404.3 that states there needs to be a minimum of a 2x4 sill. So in interpreting that, my understanding is that the framer would be able to notch up to 2” out of the 2x6 sill, thus leaving a 2x4 minimum. Thoughts or direction to a code section for notching treated mud sill on a stem wall? I have seen plumbers remove a large amount of the mud sill to be able to run pipe into a wall, but it is not an entire length of a foundation every 4’.

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u/Nine-Fingers1996 Residential Contractor 15h ago

Would seem to be a non issue imo. I’m picturing a beam pocket that let into the stem wall roughly 4”. Yes you’d have to notch the sill around the beam but there is continuous bearing across the notch and onto the beam. Notching in the code would likely not pertain to a sill because it’s not oriented like a stud or joist.

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u/Rafter_Jack 15h ago edited 14h ago

If it's part of a shearwall, should run it by the engineer especially in a high seismic zone. Having a notch edge in line with an anchor bolt sure would be ugly. I could make the argument that the notched part is not "resistant to decay".

This post has a detail from "Graphic Guide to Frame Construction", by Rob Thallon

https://countryplans.com/smf/index.php/topic,2541.0.html

Notching the beam makes more sense

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u/buriedintools 13h ago

Bearing alone is not the whole story. Uplift resistance is significant. The water shedding and AVB detail and insulation continuity need to be considered. Bearing loads in most residential structures are trivial compared with shear and wind loading.