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drainage is a tricky art
Monday, August 30 2004
Gretchen asked me at some point if I was ever going to do anything about my hair, which I haven't cut in slightly over a year. This is how it looked when she asked the question:
So I walked about fifty feet down the Stick Trail with a pair of dull scissors (the kind with the blue plastic handle) and crudely snipped off all my hair in the course of about two minutes. If you don't really care how it looks, cutting off hair takes about as long as a beheading performed by an Iraqi insurgent. Gretchen was horrified by the results and helped me tidy up the more problematic areas, particularly in the back. As you can see, though, evidence of the butchery was present even in places I could have easily checked with a mirror.
In the evening an extremely powerful thunderstorm swept through, bringing prolonged heavy rains and terrifyingly close lightning strikes. I retreated to the basement guest room where I thought I'd be safest in the unlikely event of a direct lightning hit. The back of the closet of this guest room is along a wall whose outside is completely underground and there's been a recurring problem with mold growing on its drywall, some of which has been damaged by water and repaired many times. The other day I decided to see what was behind the rotting drywall so I cut through it and ripped out a rectangle. I was amazed to discover that the drywall had been attached directly to the concrete wall and that most of the water damage appeared to be from condensation on the heads of the nails and screws holding it up.
During this evening's downpour I pulled off more drywall and was horrified to discover some surface water was managing to seep through a few cracks in the wall. It wasn't coming in fast or under pressure, but it was coming in and it had no place to go but under the basement carpet. I immediately did some web research and discovered that repairing the cracks in the wall would probably fix the problem, although I was suspicious about the long-term prospects of such a repair. Stopping the flow of water in the last couple millimeters of its flow through a wall didn't seem like a robust solution. Shouldn't I be fixing the leak on the other side of the wall, the place where it enters? That would be more like plugging a hole in a dike. It would also be impossible without excavation.
I did the next best thing, chipping out all the fractured concrete around the cracks and prepared the wall for repair. I did my best to make the hollows for the mortar bigger than the surface holes (undercutting the surface on all sides) so the mortar would be able to act more like a plug than a patch.
In one place I managed to open a yawning hole all the way into the center of a concrete block about three feet below ground level (the basement's ceiling). I could hear water flowing back in there somewhere, but where?
Interestingly, the basement wall appeared to be comprised of a mixture of cement and tiny styrofoam balls, a material I later learned is called Sparfill. The balls weren't just in the cement, they'd also been used to fill the hollows in the concrete blocks. Sparfill is supposed to have very good insulating properties. But if that's the case, why were the screws driven into it (the ones used to hold up the drywall) cooled enough for water to condense on their heads? It must be that the wall is full of water, a very good heat conductor. It looked like I was going to have to do more to keep water from finding its way into this wall. The plans for the house say that the house's uphill fill is drained by two separate pipes, one actually being below the level of the foundation. But drainage is a tricky art, and while it might be possible to drain one area well, there are evidently parts of the foundation where drainage isn't ideal. All the seeping I observed today, for example, seemed to be concentrated at southwest corner of the house's foundation; other parts of the forty foot long wall showed no signs of leaking.
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