We have an old 1920's English Tudor in Wisconsin, and just repaired a step crack in our basement where water was coming in. The crack went all the way from the base of the window down to the floor. We don't have a poured basement, we have cinder block. It was an easy fix. Our crack went really deep, so what we did first was spray "Great Stuff" liquid foam deep into the recesses of the crack - it has a long straw which allows you to reach hidden areas, and once you spray the product expands on its own. I don't know if this was necessary, but we did it anyway just to fill in the voids. This one was specifically designed for masonry. There are others designed for window frames, plumbing, etc. and each has different properties. We purchased it at Home Depot. What local contractors and our local paint store (a reputable one) told us to do is to apply UGL Drylok quick dry Hydraulic Cement. This is applied probably no deeper than 1 inch from the surface. We first chiseled out all residue and wiped the surface so that it was free of dust and particles. You want to chisel the crack at the surface to make a nice "V" shape - enough room to apply the hydraulic cement. Before applying the cement, spray the surface so that it is moist. The wet surface will help the cement adhere better, and will lessen shrinkage while it cures. Home Depot initially told us to seal the cement after it dries, but our paint store (these guys are WAY more knowledgable than Home Depot employees, in my opinion) told us this wasn't necessary unless we were planning on painting that area. We have paneling over the crack, and the cement worked wonderfully, so it wasn't necessary for us to apply a sealer. It's now dry as a bone, after a ton of subsequent rain. Because of the previous leak, the area is a little mildewy, so we purchased UGL Drylock Etch masonry cleaner. This is only necessary if you need to remove mildew, excess mortar, efforescence (salt-like deposits) before preparing the surface for the cement.

Well he's got you covered and looks like he takes the time and expense of providing other cautionary measures to protect the foundation prior to backfilling too. There's not much you can do other than seal the exposed piece if any and the window flashing should direct the water away from it as well. I don't even see the crack on the outside. Because you have waterproofing and footing drains (as was my concern with the studs on the interior, crack or not) it won't be sitting in and filling with water. Even if the crack developed after the waterproofing was applied which is unlikely (as noted by others it is a curing crack that is the result of the stepped walls drying quicker than the full hight walls) he has it properly covered and the pressure of the soil when it is backfilled will squeeze it into the crack. As for not getting any bigger there are no guarantees but because there is a window there and its a stepped foundation it wont be taking much of any load other than itself and the next possible concentrated load that comes down is over the step of the footing which is a big plus. Water freezing in the cracks is the worst enemy to concrete and he does have that properly addressed so I would not worry about it. Best of wishes for you and your new home.

No engineer will falsify a report or create an unworkable solution. But the element of unconscious bias that creates a prior restraint to thought processs enters into any transaction. An engineer may see that issue and right away think of Solution A. And know that it is the best choice for the home‘s long term viability. But she also also knows that it is the builder who is paying for that choice, and the builder will want something more cost effective. So, Solution B for Budget and C for Costcutting are developed. Neither are as good as Solution A, but they get the builder out of the immediate jam, at a price he is willing to pay. And the contractor presents B and C, to the customer, without ever even mentioning A. Because A never made it into the report at all, because the engineer knew that the cheapskate hack would not pay for it, and would rather just walk away from the project. The customer might have wanted the best solution, not the cheapest solution. The customer might even have been willing to pay the cost difference between the expensive and the cheap solution. But the customer didn’t pay for an independent report to go to them with the recommended beat solution included, as well as any others. Any design is only as good as the available budget for implementing the design. If an engineer consistently recommended the most costly approach, even though it was the best approach, she’d stop getting any calls from builders. Which might not be a bad thing for the engineer, as who in this industry likes dealing with cheap hacks?

Millworkman is correct. A large slab of concrete (regardless of exterior driveway or interior living space) needs relief cuts. These need to be planned for in advance and dealt with at the time the slab has been poured or shortly afterwards. The fact that your builder's 'slab people' didn't do such a basic thing - relief cuts - is questionable. Then to ask the same people to look at a cracked slab to determine 'fault' is working into the 'wonky' range. The last photo with the measure and the size of the crack is concerning. The other photos look rather innocent....but you never know with concrete. I suggest paying to bring in a concrete expert to examine the current condition of the slab, and the grade of the property...drainage, etc. If the builder used people who did NOT know to cut the concrete slab (to prevent unwanted cracks) then what else was missed or done poorly? At this point, I would NOT trust what the builder's people say until it is verified by a third party. As paranoid as this sounds, it is in the concrete company's (and the Builder's) best interests to say 'this is fine...don't worry about it'. It costs them less money if they homeowner believes them. And at this point, I would put the 'hardwood' flooring on hold. Because if the concrete has been cracking, it might be damaging the vapour barrier underneath...causing a WHOLE NEW set of problems with wood flooring. And besides...the slab must be FIXED before you lay wood flooring. Which means you need to bring in some concrete people to fix this anyways.