BasementWaterproofer, I have been reading through this thread with interest and was hoping for some advice, and from the Sani rep guy as well.
Particularly, you wrote:
"most basements do NOT have a dang problem with water/moisture coming up through/wetting floor. i have a moisture-vapor-drive for you lolol things are that bad for you huh, to bring up a condition that most don`t have a problem with...got milk?
Not all, Most!
for those who do, some of those problems are due to-- a thin basement floor, yeah, a 2" or so thickness and, some of those have cracks in the floor.
and then, some who get dampness/water coming up through the floor have a....blockage Under the floor which can often, not always, be freed by snaking through storm trap. would YOU like to call many homeowners who`ve had this and were almost talked into an inside drain tile system when they ONLY needed an honest/exp plumber to snake...huh?"
I just moved into a resale home where the owner painted over the floors before I saw the place and had previously done work to dig out and waterproof one external wall. Inspector noted leakage and repairs.
Now, a few months after move in, there are areas of leakage in the floors (one area the floor gets kind of pasty, while in others, a foot or two from the exterior wall, there is dampness under the paint/in places where the paint has flaked off.
There is no leakage that I have seen on any of the walls or any joints.
As you noted, most people don't seem to have this problem, and all my Internet searching has confirmed this is something of a rarity.
The house is older - was built in the 30s, and so has no drainage system that I know of at all - no gravel under the home, no sump, no weeping tiles. No idea what the backfil is, but would assume it's just dirt.
I did have someone come and give me a recommendation and estimate (from basementsystems or Clarke Basement, I think), and he suggested an internal drainage system and a wall barrier which would move the water that gets through the walls down to the internal drainage system, all of which going to a sump in one corner of the basement. Quote was $13,000.
This sani thing is superficially appealing for me given the problem and recommendation (which would still, I would think, create moisture and mould risk), but considering I don't really know anything about any of this, I am apprehensive, of course.
What you say about hydrostatic pressure and wall buckling and the like makes a lot of sense, but would the risks get worse if you prevent the water from getting through by sealing it? Seems like whether you stop it on the exterior of concrete or the interior of it would make no difference if the pressure is not relieved by taking the water/backfill pressure away, but as I said, house has been standing for 70 years with no foundation problems and so I don't think that's an issue.
Fundamnetal question, and I understand your hostility to the salesman, but I am really curious as to whether an internal impermiable membrane that bonds to internal concrete surfaces can allow me to waterproof the house and finish the basement. If the water can't get through the floor, what happens to the water? What happens to the concrete that is under the product? Will the concrete erode? If it does, how long until it breaks down? Could this have an impact on the structural soundness of the home that doing nothing at all would not?
And short of either this internal drain system or digging up all the concrete and laying down a drainage system and gravel, is there anything else that can do the job of preventing water from coming through the floor.
Thanks very much for your time.