Strouty
Well-known member
You don't know how bad I want to help with this! I love these types of projects. The more people say no way, the more it makes me want to go forward. Of course it is your money, not mine.
From the google earth picture, it looks like it further than the garage, but okay. (I was guessing 7' each)3 feet.
dont know about the merits of the beam sizing as i am not a structural engineer...just looks too small in my eyes. the real issue i see is that you create a joint at that location for water to infiltrate on the yard side...dont know what the solution is just something to think about vs. setting a continuous slab on a steel beam. whats the hang up with 8' ceiling at a beam?SE just confirmed that if we use a concrete beam that integrates with the grade beam to set the garage wall on, we don't need to use a steel beam at all. This saves a lot of money and headache.
We'll need to put a couple (movable ?, steel ?) posts under it, but the only place that will not be a 9 foot ceiling in the bunker will be where this single beam goes, right under the garage wall. There are a few more details to it than that, but that is the essence anyway.
Using a steel beam would have been a headache because it has to sit entirely under the roof pads. It would be hard to limit its height to 12", meaning the clearance under the beam would have been less than 8'. I was trying to avoid that. I'm guessing the beam would have needed to be 16 or 18" deep.
The key to making this work is that the integrated beam can be 32" tall. Beam strength varies greatly with height. We couldn't make a 12" tall concrete beam work, but its straightforward to make a 32" concrete beam work. Forming and pouring this beam is going to add time to the construction schedule, but a steel beam wasn't without hassle either.
The beam needs to be under the garage wall because the snow load from the roof is supported by the garage wall. Actually, it could be designed so that the beam isn't directly under the wall, but its simplest if you can and in my situation it works out well.
Hopefully my chicken scratch diagram clarifies the situation a bit.
We haven't calculated rebar content yet, but I'm pretty sure its going to come in well under the $8,000 I budgeted for beams, posts and rebar.
FYI, there is a bit over 3 yards of concrete in the 34 feet of integrated beam.
Don't get your ******* in a knot about the geotechnical and excavation issues. We'll figure them out once we get the facts.
One other thing you should consider in your plan and cost estimates is to get yourself bonded (and if applicable, licensed) as the GC.
The purpose of the bond is insurance for the unexpected. Even, assuming the geotech and other engineers say everything is okay-dokay, your neighbor 'could' claim the cracks in his garage floor are from your construction (we all know concrete slabs do/will crack, but). Worse, something catastrophic happens and damages his or your $1M+ houses. The 'claim' isn't your issue, it's why you paid insurance.
Digging nearly 10' deep in close proximity to existing structures is so risky ...
I'm not hating on your plan/dream, but I would be pretty scared of the risks involved.
I don't think he is in CA, he probably doesn't follow the same rules. I don't think I could even visit CA, I would probably drop dead the second I walked over the state line, all these chemicals that I use cause cancer in CA.

Worse, something catastrophic happens and damages his or your $1M+ houses.
Digging nearly 10' deep in close proximity to existing structures is so risky ...
I'm not hating on your plan/dream, but I would be pretty scared of the risks involved.
Pads need joints so they can float or they will crack. Especially because one of those pads is inside the heated garage and the other is outside under the ground.dont know about the merits of the beam sizing as i am not a structural engineer...just looks too small in my eyes. the real issue i see is that you create a joint at that location for water to infiltrate on the yard side...dont know what the solution is just something to think about vs. setting a continuous slab on a steel beam.
Just want a space with some headroom, especially if it might be part of a work area.whats the hang up with 8' ceiling at a beam?
There are limits. I bought extra insurance when I did the reno. This project will be beyond the limits of homeowner insurance.As long as the OP has hired an engineer and hires competent construction crews, his homeowners insurance should cover the rest.
There are limits. I bought extra insurance when I did the reno. This project will be beyond the limits of homeowner insurance.
I'm not hiring any construction crew. Me and a helper or two are doing this project, unless we get overwhelmed. I'll make good use of advisors... just as we did on our reno and on the landscape project we did last summer.
Just want a space with some headroom, especially if it might be part of a work area.
Might also be able to lay the membrane on top of the whole thing, then cover it with soil.
Nope.Are there seismic considerations in plan?
There are plenty of skid steers that meet your criteria and they can load a wheeler. I would look harder. I am not up on model numbers, but I would contact sunbelt rentals and see what they have.
EZ, that would work fine for open spaces, but I can't imagine using it in a confined area.
Thanks ! I'm doing my best. It helps that the project has an enforced start date and I get to spend a lot of time preparing.I just skimmed the last page, but the OP has done a great job of analyzing this.
