Hi, after ten years of cold winters and numerous searches on this and other forums I am asking for some help and hoping someone might have some ideas that I haven't thought of. thank you in advance. I have a 160 year old 2 story stone house near hamilton ontario. when I bought the place I gutted the upstairs and spray foamed all of the walls and added extra attic insulation. the basement however has some challenges: - it has a limestone bedrock floor, -it is just barely high enough for me to stand up in (with my head between the floor joists (cedar logs) in one half and the other half is a crawl space. - the basement half (not the crawl space) I believe has been quarried out to get the depth that it has as the ground is very shallow, therefore, in the spring or after a really big rain it gets a lot of water running through it, not just wet but a solid garden house type volume of water will flow for a day or two when the conditions are right. the sump pump keeps up but the water comes in from every wall and flows across the floor to the sump. I used a saw to cut some channels to direct the water and everything in the basement is raised up to keep it from getting wet. - the basement contains all of the utilities including water and furnace. these are built onto large concrete bases to keep them dry. (done before my time) the floor is remarkably level but in spots has about a 4 inch variation in height, in one corner there is a 4x8 area that was under the original stairs were the bedrock was not quarried as deep as the rest of the basement and is about 6 inches higher than the surrounding floors. When I originally renovated I spray foamed all of the basement walls and the crawl space floor. On the basement walls, due to my concerns of water, I ran delta foundation membrane on the inside of the wall 2 or 3 feet up from the floor and spray foamed to this so if water comes in from outside it could drain down to the floor. I have no plans to have the basement be anything but storage and utility space but the cold from the bedrock floor and from stone interior foundation walls means that the main floor of the house always has cold floors. I would like to fix this. Also I mostly heat with a wood stove on the main floor, if I ran the furnace more often I would probably be happier with the floor temperature but I would basically be running an oil furnace just to heat the basement with my heat dissapearing into the bedrock. The obvious solution is to put clear gravel down with EPS and concrete. It would mean that I would have to smash out all of the concrete bases for my existing utilities which could be done but my concern is that I would be turning my low ceiling height basement into a crawl space which I dont want to do, being able to walk around in the basement and easily get to a freezer and things on shelves is pretty important. to gain a bit of ceiling height from this option I could do the gravel EPS and then plywood but I would worry about the impact of the water, and I would still lose significant headroom. I would love to find a solution that would let me insulate the floor in a manner that would not be impacted by water and not lose too much headroom - I dont think that this situation exists. furthermore, the interior load bearing stone walls that connect to the exterior stone walls would continue to be a heat sink unless I insulated them too which would add considerably to the job. I am tempted to just give between the joist insulation a try it would not be too expensive, it could be undone, and I dont think that my basement pipes and such would freeze because the stone floor usually stays above freezing. Thank you for any thoughts that you have, they are appreciated. D

What about using hydronic radiant floor heating? While we don’t normally recommend below-floor plate systems, because they are very inefficient at getting heat up into the living space and somewhat expensive, this might be a good situation for this type of system. You would only need it to provide enough heat gain to keep the living space floor from getting cold (e.g., keep it at say 68F). You would need to insulate well enough below the PEX so as to not lose too much heat to the basement space, but some lost heat should help keep the basement above freezing.

thanks, I dont want to add a whole new heating system as I already have forced air and woodstove I think I would be better off to just run the oil furnace more often than add radiant.

I wasn't suggesting a new heating system, just augmenting the existing heating system to place a little HR heat in your problem floor. But just insulating that floor from the cold basement will likely greatly improve the situation. You could also put a small electric baseboard type heater in basement that only turns on as needed to keep basement above freezing temp.

Insulate the floor joist would be the easiest thing to do. I would attack the water problem from outside. Gutters, exterior drain pipe to channel the water away from the house. If your heating with a woodstove build a plenum behind the stove and blow the hot air into the crawl space.

thanks, not really possible to deal with water from outside, the basement is quarried into limestone bedrock and water flows on the seams, the only way would be to quarry out the exterior and then install drainage, there is some slope away from the house but the water problem is never gonna go away. for most of the year it is dry, but when water runs it runs hard