You wouldn’t want to build a home in a place where there was never any rain: life is sustained by water. Life giver that it is, it is also the most pervasive destroyer of building materials with the able assistance of other, simpler forms of life: the wood destroying organisms (WDO’s). Plus it’s just a bother when it drips onto your head when the icemaker pan on the floor above at the hotel where you are staying, leaks; of course, in the middle of the night.
Water intrusion amounts to over half of the immediate needs corrections I have seen in the thousands of buildings I have assessed. (When I arrive on-site, I generally make a comment as to whether it is the roofs or the HVAC systems which need attention. I generally get a “How did you know?”, response). Needless to say, the latter issues of HVAC are generally manifested in the creation of liquid water in the wrong places by condensates which leak, or are created in the wrong places. Same for plumbing: pinholes and sweating leads to destruction by our friend, water, (waste water is water too, just nastier and smellier).
Let’s confine today’s chapter to stormwater: that would be rain, snow, and ice. I have been to seminars given by my colleague, Joe Lstiburek, which have the flavor of an old timey tent revival meeting with a room full of knowledge seekers chanting “All claddings leak!”, “Flash for cash!”, and “Conduct and control the water: down and out! “.
Lots of commonsense here:
- “All claddings leak!”: the exterior siding on buildings, and even those lovely architectural shingles are there for appearance first but will shed at best 98% of the water impinging upon them. Like the rest of the building, water protection is a system, detailed with backstops to treat the exceptions: penetrations, intersections, and ice dams as minor trifecta.
- “Flash for cash!”: this is one of the backstops, where two systems or a discontinuity appears, insert solid flashing. I once met a man responsible for the challenges presented in the exterior envelope maintenance of a major hotel chain. He said, “Show me a window system that is not caulk dependent.” At the time, hard to find. If caulking is applied with 99% perfection, 1% of leaks can cause a world of problems.
- “Conduct and control the water: down and out! “. Gravity is with us today, and except for capillarity (which will be a whole other chapter) is our ally in allow our controlled water to reconvene with the ground. The “and out!” emphasis reminds us that if we bring the water into the basement or under the building it is still there to raise havoc. I advised a client on a level lot not to consider a full basement for all the right reasons: level lot, high water table, no adjacent property to give the water to. He insisted. I saw him some years later and said in effect, “You were right, I have two pumps that run all the time and had to put in a generator, because when the power went off for 6 hours, I had four feet of water in my basement.” So much for inexpensive storage for things you should (and now that they are moldy, will) toss.
So water, that nurtured life, when it began, can also work to tear apart, the works of man.