2 contractors. 2 different waterproofing solutions
1924, 2+ story colonial with poured concrete foundation. Lot slopes away from the house in the rear, but is about level with the street in front--though grade pitches idiotically toward the foundation in a few spots. Slope can't be fixed until spring, but I want some protection in place before the local Ice Age thaws out during the spring rains. Clay soil.
- Pretty high humidity, somewhat remedied with a large dehumidifier
- Occasional small mystery "damp spots" on floor after heavy rains in random locations
- A small rivulet of water appeared twice during bad storms, always in the front of the house, always flowing from L to R, where it disappears into an open pit containing a now-sealed cleanout or drain pipe. The rivulet always rises out of the floor: once from a wooden post (now gone) that penetrated the concrete to anchor in the dirt below, and once from around a recently-replaced water supply line.
- Efflorescence in various places across all 4 walls, along with areas of crumbly surface
I brought in two different contractors, with two different recommendations. I have no idea who is right.
Both recommend an interior French drain with sump along the front of the house where the Mississippi occasionally appears, with small elbows coming back to where the corner ends.
One suggests doing a drain around the whole basement now, because it's cheaper than coming back twice, but acknowledges that may not be necessary.
Here's where they diverge.
Contractor A says the efflorescence and chipping are coming from dampness outside penetrating the concrete; any waterproofing material like tar is probably long gone. He suggests doing a Thoroseal or similar application along the crumbly areas, after power washing off the loose concrete.
Contractor B says the efflorescence and chipping are coming from condensation reacting with the cold concrete walls. He suggests stucco up to grade (where the crumbling stops).
Obviously, the fact that the crumbling stops at grade doesn't prove either fellow right. Foundation above grade is above groundwater, but it is also obviously warmer in summer.
Who is right? What should I do?
BTW, no, there isn't an extra 18 grand lying around to dig up the front yard and waterproof from the outside.
Thanks for any ideas!