Client built a house over as 80 yea
Client built a house over as 80 yea
(OP)
Client built a house over as 80 year old basement (old school house boiler room), covering the ground on three sides outside basement walls. Ten years later, has major problem with water seeping through the old concrete walls of basement. The exterior of the basement walls can only be accessed on one side by excavation to permit installation of a waterproofing membrane. Anyone have recommendations on getting the other three sides dry (or at least, drier)? Basement is 35' long × 15' wide × 9' high, with concrete ceiling (floor of old school house); no data available on thickness of walls.





RE: Client built a house over as 80 yea
Injection of grout into the "voids" may help, but if dirt is there also, later to be washed in, maybe not so good.
RE: Client built a house over as 80 yea
RE: Client built a house over as 80 yea
The basement's foundation is of concern, as is the condition of the basement walls; thought about building a reinforced CMU wall all around the basement interior with mastic/membrane water proofing on sandwiched tightly against the inside surface of the existing concrete walls; two purposes, to support the basement roof & 2, to hold back the any hydro-static pressure that may come through the existing concrete walls trying to push the WP off. This would be very expensive labor vise since every bit of material would have to be hand carried through the house and down the stairs to the basement.
Surface water could be migrating around the basement from the one uncovered side and owner has been advised to correct the drainage problem there - to get positive drainage away from the foundation. When that's done, it may take months for the water that is present to percolate down and away (as well as in); another year waiting to see may not be unreasonable. Is there a "sealant" slurry of some sort (bentonite, maybe others - lime, flyash?) that could be injected into the soil around the outside of the basement walls - would have to drill holes walls the through the floor above outside the basement below and try to get slurry down to the basement floor level with a long pipe nozzle - never have ever seen it done before; effectiveness could not be verified without observation holes through the basement wall at/near interior floor level.
RE: Client built a house over as 80 yea
RE: Client built a house over as 80 yea
RE: Client built a house over as 80 yea
At my house the former owner had landscapers do something that looks nice, but sure was wrong. All around the perimeter (except for walks and driveway) a trench was dug extending out about 3 feet and 8 inches deep. A fabric was placed in bottom and clear stone added to fill it up. No weeds can grow there, but that was a great place to catch surface water and then feed it to perimeter drains. In some weather, the sump pump ran continually. After the treatment, getting rid of that trench and surface regrading, extending downspouts way out the sump pump might run once a year off and on when ground water rises after big storm. House sits only a few feet above groundwater level.
Treated areas stay greener than elsewhere doe to bentonite holding moisture.
Stone area had then first the waterproofing, a black sheet of plastic and one inch layer of stone. It looks the same as before, except no seepage.