This was not an engineer. This was a company to fix the sag.
This is the engineer report. I thought I posted it already, but maybe not
Good to know the report I commented on was not from an engineer. I just skimmed previous comments so I might have missed this report – sorry.
I suggest you talk to additional contractors but this time ask them to address their proposal directly to the comments and recommendations in the engineers report. You could even ask the engineer if he would be willing, at his hourly rate, to comment on the proposal that looks best to you.
I have never seen a home without subfloor ventilation – but that is very likely because I am native to CA where cold isn’t a problem. Vents along with subfloor/plumbing insulation is the obvious costly solution (but still cheaper than future problems due to moisture). Try talking to the County building department to see if there are other solutions; maybe something like vents you close in the fall and open in the spring are an option.
I don’t understand the suggestion of a subfloor fan unless it is intended to accompany a number of vents that is inadequate for convection ventilation. I suggest you ask the engineer how that would help (again, it might well be something I am unfamiliar with).
The engineer makes strong recommendations about drainage – take them VERY seriously. My lot is flat so my downspouts drain to pipes under the lawn that outlet through popups near the street. The last 10 ft of pipe is perforated so water doesn’t stand in the pipe; I also anchored the solid pipe so it won’t “float” in saturated soil.
Is subfloor ventilation still needed if exterior drainage is fixed? I would hesitate to not ventilate, but if you regularly check the crawlspace for signs of moisture after fixing the drainage, perhaps you could get away with no ventilation.
Have you talked to others in your neighborhood? It is likely the ages and construction methods were similar or the same so problems and solutions likely are too.