Hi,
Sounds like you are undertaking a noble task.
I think everything you wish to do makes sense. The stone foundation will be fine. The thing to consider is that water is probably entering or coursing through the basement now when it rains. With wooden and broken concrete floors it disappears quickly, but the humidity remains. When you pour the slabs, you could discover that now the entering water is trapped with no easy way out, and you will need to do interior or exterior foundation drains. IMHO, exterior drains will be more expensive but better in the long run, because of your foundation material, which founds like fieldstone, at least on the Federal-era part. When you dig around the perimeter to lay the drains just below slab-level, you will need to wash and repoint (perhaps in areas re-lay) the stonework. This will pay off in the long, long term.
Another outgrowth of drying the basement is that the wooden floors may crown. This is the opposite effect of cupping, which they probably did a long time ago, but have been sanded flat on top. When they eventually flatten themselves by drying out, the centers of the floor boards will appear to rise. Just think of how much character they will have! There will also be gaps at the edges of each plank.
Other wood components will dry out- doors will become much looser-fitting, miters (if any) will open up at the inside, etc, etc.
Good luck, though. It is necessary to make it safe and habitable.
Casey

I am in upstae NY as well, with a 160 y.o. center hall Greek Revival - 2 story - building w/o any insulation, so, I can relate!

My cellar has two areas, one with turn-of-the-century (the last one!) thin poured concrete, and the other part with just dirt.

I'm not sure you need to dehumidify the entire house (or how you would do that short of installing a/c.) But you can run dehus in the basement. I do, during the warm months.

But you can also improve the moisture issue in another way: by installing a vapor barrier under the floor (if you're going to poured concrete) or just laying it down on the surface of the dirt sections. No, this will do nothing for radon (though probably will retard it some, but not enough to be a satisfactory, or safe, radon reduction technique).

You easily install insulation before you repair the slate, as well. But I'd wait til late fall when the bats have departed for the winter.

I have been scheming to get radiant heating in my house for years, as I think it's the nuts. We heat entirely with wood and pellet burners, now. However, I have concluded that it would be unsuccessful because my floors are about 1 1/2 inches thick and I have no possiblity of insulating my walls so the demand would be heavy and the thermal transmission rate slow. Plus my flooring (though completely accessible in the cellar) is made of very wide (up to 20" wide) t&g old-growth pine, and I think it would not react well with radiant heat. I do plan to use radiant in parts of the house where I still have tamped-earth (dirt) floors, or rather no floor, when I incorpaorate them in the reno.

However, to your original question, I doubt you could injure your house with using dehus in the cellar compared to the dryness of a heated winter.

By the way the base of your foundation is also likely to be 'way thicker than two feet. Mine is probably approaching 3 to 4; the inside is fairly smooth and regular, but the outside stones stick out quite deeply, and in an irregular way, into surrounding the soil.

Instead of painting the inside of your celler, you might find white washing an acceptable alternative and one the would not require more than a vacuuming and loose brushing of whatever is there to prepare the surface. It is the traditional wall "paint" and does well on dampish stones, though it's rather short-lasting compared to paint, only lasting maybe 3 or 4 years, before it needs recoating.

HTH,

Molly~

One interesting thing is that, throughout the house, doors that will close in winter won't in summer. So what you mentioned about doors closing will be good, I think!

(We also aren't "summer" people - moved to upstate NY because it was supposed to be cool - my mom remembers a time when she knew she had to go to summer swimming lessons if the thermometer said 60 degrees. I feel like dehumidifying will help with the oppressive humidity.)

Had not thought that there might actually be water getting in - thanks for the warning. One concern - we have really nice parkay wooden floors on the first floor - I really wouldn't want them to buckle - but I suppose it's a risk.

The inspector told us that there was an area where the foundation was very slightly coming in because there have never been gutters around the roof. We graded the soil, but the soil was not interested in maintaining the grade.

At any rate, we have occasionally discussed drains with people, and they say, "Drain where?" The water table is really high and this area is pretty flat. We'll have to work on a solution, but we will definitely look into exterior drains. Thank you also for the warning about repointing the foundation.

As for whether or not we need to dehumidify the house - I suppose we probably don't need to, and I guess the cost of a/c compared to just the basement will probably determine that in the long run.

The vapor barrier is probably a good idea. The slate leaks, which is why we didn't want to put in the insulation. And thanks for the warning about the bats and white wash.