This is an unsual one. There's a cement block chimney on a building's exterior. The chimney actually goes below grade through an asphalt parking area, and the flue comes out into the basement below grade. The chimney was replaced this summer from just below grade.
Here's the problem: we just had a quick thaw, and about 200 gallons of water ended up in the basement by traveling down the flue, through the furnace, and out onto the floor. Examination of the base of the chimney shows an unsealed 1/4 - 1/2" gap between the chimney block and the asphalt. This appears to be the entry point. Ice build up from earlier storms had resulted in reverse grading, directing melt water back toward the chimney base.
Any suggestions on how to seal this, keeping in mind it's below 20 F here? Currently, the block is completely uncoated. Any other detailing areas to look at?
Thanks, I'll check in later.