Thickness is 8". The stem wall height, from the lowest adjacent grade, is about 7.25 feet. Their lot is sloped towards the front and they don't want to step their foundation.
I suggested that they need engineering even if it is only supporting 1-story wood-framed building.
I can't find any section in the residential code regarding max stem wall height before they need engineering. There is only info on minimum clearance above grade and min depth of embedment.
Yall got anything for me to flex on these dudes?
Edit: forgot to mention project is in SDC E
IRC R404 has a table for 8" wall that gives the required vertical reinforcement based on wall height and unbalanced fill height
Yes, I'm curious if OP knows there's a lot of prescriptive stuff like this in the IRC. Some stuff will not calc out if you check it but it's fine because it's "works"
I've found the same. It's pretty crazy how much the IRC actually covers. I think there is a big gap however in how well it ends up being applied on an actual house.
Default in the field for a situation like this should be to express uncertainty about the need for engineering, and then check afterwards, since the IRC covers so much.
Good to know. I’ll admit I’m more well-versed in the BC over the RC.
Follow up question though, does the prescriptive stuff in the RC cover wall anchorage? I’m in SDC E
I believe that should be listed in the table footnotes.
There's a section that recategorizes a residence to SDC D2 if the structure meets a few different criteria. Can't remember which section at the moment but just go look around
Just let them know if the municipality makes them get an engineer you won’t be automatically okaying what they did, and you’ll charge as much or more than if they just had you design it in the first place. But say it nicer.
Stem wall, so foundation wall supporting a residence? I would probably look at that as a basement wall per the prescriptive tables in the IRC. These generally go up for 9 or 10ft backfill with various thickness and reinforcing patterns. The code does not, however, address top of wall anchorage (at least since like, 2006 I think? Not sure why they removed it) so you would need to provide an engineered design for that.
Also, this is why cheap residential design sucks.
Ah, my bad. I think I see basement walls without engineers commonly. I think IRC covers up to 8'.
https://codes.iccsafe.org/content/IRC2021P3/chapter-4-foundations#IRC2021P3_Pt03_Ch04_SecR404.1.4.2
Name checks out
Yeah, max without an engineer is 4'.
https://codes.iccsafe.org/s/IRC2018P5/chapter-4-foundations/IRC2018P5-Ch04-SecR404.4
Not retaining wall. Just a tall stem wall at the crawl space
He didn't say retaining wall though.
Also the last sentence of that code section is that it does not apply to foundation walls supporting buildings.
Does OP know the difference?
Are you trying to flex on him?
Stem wall, retaining wall, slender wall, steel sheet wall, CLT wall, soldier pile wall same shit to me. No difference
Is this a basement wall or a retaining wall? Retaining walls aren’t covered in the IRC if memory serves. (It may not, BIL brought over the naval strength rum.)
Basement. There is no retaining. I only asked because this stem wall (I guess it is considered a basement wall now based on other replies) is a bit taller than usual
Check vs. the prescriptive tables in the IRC, if that code is adopted in that location
Looks like they have it. But nothing on wall anchorage though
There are requirements in there for that- anchor spacing for the floor platform sill plate to the wall.
My thought is it’s still too tall. 7.25 feet from t/wall to exterior grade + frost coverage could be beyond the tables, depending on where this is.
I’m talking out of plane anchorage per chapter 12 of the ASCE. Not the in-plane anchor bolts
Ah gotcha- seismic never controls where I practice so I’m used to ignoring it.
I would find a better project to work on. People with all the answers don't need any advice.
Over 4 ft, IRC or not, an engineer has to sign off on it. This is required in most municipal codes. After 4 ft It starts depending on more things than the concrete and reinforcing. Now it starts to depend on the soil type, footing, wall and footing proportions, adjacent loads, reinforcing detailing, passive and active soil pressures, blah blah blah, in addition to the concrete, reinforcing, and reinforcing location.
This calculation is iterative and there are a boatload of variables. It requires engineering software if you dont want to write a thesis on doing one calc.
Hey or you could just cross your fingers. This makes engineers way more money fixing it later