Rufus Laggren wrote:Assuming a concrete basement (also CMU - cinderblock), some sealers seem to work, both inside and outside the wall; outside usually works better, of course. I have used a "Thoroseal" product inside a CMU full height basement with regular flooding problems; in the last 3 years it seems to have helped a lot.
You can garden on slopes. It is doing earthworks on slopes that makes a bad, I.e. Unstable condition.
Any slope 20 degrees or greater is supposed to be left alone (not brought into production). Still, it might be a good idea to remove the trees closest to the house so they don't fall on the house. You could use those trees to make a terrace Sepp Holzter style. The plant shade tolerant species in the terrace.