Lawn Drainage Problems - Getting Water in our Basement
We need some advice with regards to how to handle water in our basement.
Since construction 2 years ago, we have been battling with water coming through the new construction basement walls, despite several of our efforts. We have exterior foundation drains and interior french drains all running to a sump pumped to the street since it's below street level, and our downspouts are running to the street. The floors remain dry but the block on the walls keeps getting wet and drips down to the drains. The only barrier that our contractor used was a tar paint on the exterior of the walls, which obviously didn't work. Our grading is now almost 4" from the vinyl siding so we can't really build it up anymore to drain away from the house. The problem is that our whole backyard is on a slight pitch towards the house.
Here's where we need advice:
One of the landscapers we've brought in for estimates recommends that we line the exterior of the house with flashing that will come up the 4" of cement and slightly overlap the siding so that we can use fill to pitch dirt away from the house, and then run that water into a perimeter drain that will run to the street.
Is this a bad idea? Are we opening ourselves up to an insect (termite) problem or any other problems? Another landscaper suggested that the only way to do this "properly" is to remove the lower rows of siding, and then to do a moisture barrier, lath and cement over the exterior wood down to the foundation cement (instead of using flashing) so that bugs and water can't get behind it. Is the flashing sufficient?
Here's a picture of the area we're talking about: From House Drainage