Well, I’ve done this crazy thing and made my house smaller. I poured a concrete wall perpendicular to 100-year-old limestone walls. Now I need to waterproof and backfill. I can only run a footer drain into an interior sump, no way to run those drains to daylight. I’m thinking about using betonite to waterproof, especially where the concrete meets the rock. Will that stuff work against the stone?
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bentonite is nothing but dirt, its a clay that swell
For my money, bentonite's the best waterproofing there is, but it requires backfill pressure. Don't quite understand your application. Sounds like you'd do well to run poly out from your walls as far as landscaping allows.
PAHS Designer/Builder- Bury it!
As part of making the house smaller, I'll be eliminating some of the basement (filling it in.) Imagine a rectangle cut in half by the new concrete wall with half of the rectangle getting filled in and becoming the outdoors. So I will be backfilling against my concrete wall. The bentonite will have pressue against it. I intend to leave a portion of the old stone wall in the filled-in part but will have a 90- degree corner where concrete meets stone. That's the joint that most concerns me. I'm wondering how well I can get the bentonite to fill in that corner. If it's flexible and can be molded a bit before we backfill, I should be able to stuff it into the corner. Then I can just adhere the sheets to the flat concrete surface.Sorry to be so long-winded. I know it's weird. Positively un-American!
Got it. So long as you don't have substantial air voids between the bentonite and your walls, you'll be fine. When you say "adhere the sheets...", are you talking about cardboard panels or poly rolls?
Panels have often been problematic for installation, rolls pretty much foolproof. Backfill pressure before the bentonite gets wet is paramount, as is a termination bar at the top. You want a bentonite rope for that corner, under the rolls. Or a bag of loose granules that you can pour into the void in the corner (behind the rolls). Not the marble-sized nuggets we use to seal well casings.
I'd also definitely install 6 mil poly sheeting sloped away from the house. Cheap and provides a primary watershed. Just tuck it under your termination bar, backfill to a slope, roll it out, and backfill (over scrap carpet if you've got rocks). Very possibly a concept you haven't seen. It's all we use on our underground houses, absolving need for bentonite. In your case, I'd also use bentonite. 6 mil poly is assuming you're removing, or at least lowering, the abandoned walls.
Not long-winded, gotta explain enough for everybody else to understand. You're correct about unusual. Presume you have your reasons, other than yard enlargement.PAHS Designer/Builder- Bury it!
I really appreciate your detail. What do you mean by termination bar? As you can see, I'm pretty inexperienced with foundation work. I was thinking about the panels but I can look into the rolls. Any brand recommendations?And yeah, I don't need a bigger yard, but the house was a stupid design. And I'm not into cleaning, heating, furnishing, etc. space so that I can have a two rooms for every purpose. This is what I see in the mansions. Five different sitting rooms, three places to eat, and so on. I'll have a lovely sun room that faces east when I'm done. In fact, I've already built the wall in the existing space. I'm building from the inside out!
You can get the bar from whomever sells you the bentonite, which is a specialty item here. Aluminum strip with screw holes. Goes at the top edge to keep water from running down where you have no backfill pressure. IIRC, you need 25 psf pressure for the bentonite to work.
I've never used panels, just read about problems, generally on gov't projects. The rolls have granular bentonite stuck to heavy poly, 4'x24' or thereabouts. Bentonite goes to the concrete of course. 95 lbs/roll. http://www.tremcosealants.com/fileshare/specs/07132.DOC is what I've used.
http://www.alliedbuilding.com/products/productDetail.asp?ProductID=30280530 shows rolls 40"x37'9" for Swelltite. Pretty sure they also offer a bentonite butyl combination.
Pretty funny about you reworking your house. Most would have sold it and gone elsewhere. You must really like the location. There is a disconnect between large houses and lack of household staff.
I had a guy ask me if I could turn his (now unused) second floor into a boat garage as he couldn't leave it outside and wasn't allowed a detached garage. Architectural approval required in his subdivision, but we could have worked it out. His wife didn't think it was a good idea. Sounded like fun to me. 5000 sq ft house (plus basement), 2 occupants.PAHS Designer/Builder- Bury it!
Yeah, I'm sitting in the middle of 250 acres in SW Wisconsin. And it's on the end of a dead-end road. Location, location. Thanks for the info. I'll look for a distributor here. It doesn't seem too common but I think there'll be someone in Illinois, if not closer.
Don't forget a followup with photos.PAHS Designer/Builder- Bury it!