Insulation, Radiant and Vapor Barriers - No room to crawl in crawlspace

I've got a 1901 farmhouse that is sitting on a foundation but has essentially no crawlspace. I've peered into the space from the partial basement area but it is basically unaccessable. What I did see was that the floor is dirt and the floor of the house is not insulated. I live in Minnesota and this makes for extremely cold floors, but I can't get in to insulate the floor. (The whole place is extremely drafty too)

I'm wondering if I should attempt to insulate the foundation from the dirtside this spring, and if so how far down do I need to dig? What product should I use for insulation? and what do i use to cover the insulation that is exposed above grade? etc.

I've got plenty of other stuff to do and it's far from spring but I need to keep this in mind as I budget for repairs

Ideally you should insulate to the footings which should be below the frost line. I'm guessing this level in Minnisota is at least five feet. If the footings are not to frost insulate down to the footing and horizontaly from the wall a couple of feet. This will keep frost from getting under the footing and into the crawl. While you have foundation wall exposed, this is the time to upgrade the damproofing and drainage tile. Type II expanded polystyrene and type III & IV extruded polystyrene are suitable for exterior insulation. To protect the insulation above grade you could use a wire mesh & stucco, a cement mill board or pressure treated plywood. A "Z" flashing or other techniques at the top of the insulation will keep water from leaking between the insulation & the wall. Remember to keep adaquate ventilation in the crawl space. A vent of one square inch per square foot of crawl space. The vent should be closed during winter and opened in the summer. A poly sheet should be spread over the dirt floor but as you said, there is no room to get under there. Best of Luck.

Greetings,

If you go out horizintal to the wall with foam, you have to out at least 48". 24", you're wasting your time.

I have relative who redid a big home on the natioal registry and he is planning to remove the subfloor and use plastic vapor barrier and radiant barrier on the floors and sides.

The other problem of course is the amount opf moisture you get from this type of construction.

Thank you for considering my opinion.