[Nealtw]

Is one at ground level and the other in need of stairs off the porch?

 

[Nealtw]

They both require a step onto porch.

I don't understand what he wants it for.

 

[Nealtw]

The question is about the foundation wall extending down to the basement and closed off vs the plan with the larger porch is unexcavated. Was wondering why the excavate all the way down and finish off the porch well below for the smaller porch.

Is one door at the basement level?

 

[Nealtw]

The question is about the foundation wall extending down to the basement and closed off vs the plan with the larger porch is unexcavated. Was wondering why the excavate all the way down and finish off the porch well below for the smaller porch.

Here, they dig the hole for the basement 5 ft bigger all around for safe working in the hole.
So the smaller porch would be in that 5 ft so they are saying add another 4 ft to the width and include that foundation in the hole
The bigger porch is outside that 5 ft hole and only needs to be down to frost depth.

 

[Nealtw]

OVERDIG! That makes sense. So the main reason is efficiency and as well as the over dig area if it remains mostly undisturbed in the bigger/deeper porch allowing the soil to not have to settle then it's good and they go 42" below after the basement is backfilled for porch footings. But like @Matt1963 is saying that is assuming they do not even have to dig even further which then in turn that entire porch area would be done with the basement like the smaller porch and filled with dirt and then do the slab as usual I'm assuming since it's possible it could be in the overdig area.

Both plans do have basements and to the right are the garages.

We have had builder that will not dig the whole garage to basement level and have the far corner at frost depth. With stepped footing and working up and down slopes.
It makes for a royal pain in the ass for the people doing the foundation. If it is a close call have it dug out.

 

[Nealtw]

Makes sense so the the bench cut area is pretty much left alone and the 2ft clear area would just be back filled and as you stated there is a 42" cut after the fact so porch can be trenched out after and either poured or cmu block. The reason behind this was to see how excavation efficiency plays a role and this can be done with budget based on design, yes.

You save a little in concrete and back fill. We sometimes get that for a deck post footing that will be some distance away from the house.

 

[Nealtw]

Okay I see what you are saying now so it's all done at once. The area up against the foundation wall say if the wall is 8' and there is a 2' setback that is completely dug out all 8' down (the area you have showing in red) but 6' back where the bench cut/porch is (area shown in blue) you take down only 42" and pour the footings just for the porch so not as deep as the foundation wall and build up the porch all in one go. The area between would be re-filled though I'm assuming (shown in purple). P.S those racoons are too damn cute lol.

How far is it, your red line showing eight feet deep would be 5 ft from the house?
The depth of the higher footing is dictated by the distance to the raised footing.

 

[Nealtw]

That drawing markup is not to scale, it was just for discussion, so I don't know how far out an excavator at your site would choose to dig. I assume that is not your house anyway because both drawings of house designs are so different.

So here are a couple interweb photos that might help put this to rest (they are elusive photos googling with the word "bridge"). There is a gap in the overdig under the higher elevation footing - and this is where the "CMU Lead Wall (Typ)" comes into play, I believe they are saying to infill under the bridge with CMU after the pour has been stripped ("Typical" means it is a contractor decision on where and how many, not the designer to dictate). I haven't ever seen the CMU, usually you just load up the rebar at the bridge.
View attachment 722531
View attachment 722532

I spent 3 hours explaining that bridge to a new engineer one day. He made 4 phone calls before he passed it and let us pour concrete. We lost a day over that.

 

[Nealtw]

Did you leave out "new YOUNG engineer"

He wasn't young but new to us. I explained to him the whole site had been compacted but the slope was not, he could not get his head around that. At one point he agreed with everything I said but still wanted to check with others.