Notes from my Knapsack 4-26-18
Jeff Gill
Machines for keeping the damp off
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What's a house, after all? It is, as Maslow's hierarchy tells us, "shelter."
Our constructed cave, our burrow with windows, a treehouse without the steep first step: a house is where we keep the water off our heads.
From the roof to the walls down into the foundations, most of the structure and function of a house is to keep us dry. Because water is a solvent, and unless we want ourselves and all we own to be melted down and washed away, we need a machine for keeping the damp off.
So most of us have shingles up above, but they lie atop a series of layers – tar paper, plywood sheathing, venting poking up through to allow vapors and gases and such to pass back through here and there – that rest upon the trusses which weigh down onto the framing which carry that weight down onto the foundation and/or beams which carry it all down to the solid earth.
Outside, where we don't have windows breaking through to let light in, we have more layering to keep water out: siding or stucco or paint, overlaid onto what's usually some sort of moisture barrier sheeting, the exterior sheathing which nowadays is usually plywood of some sort, and that nailed onto the supporting beams and studs. They're made of simple unfinished wood, protected from the damp by that siding and sheeting and sheathing.
Even working from the inside out, paint onto wallboard with wainscoting or crown molding or baseboards, there's a certain amount of the structural logic that's there to keep moisture from splashing and washing and dissolving and eroding the building from within. Those "decorative" elements are there so the brooms and vacuums and shoetips and the slings and arrows of outrageous fortune don't break down the architecture one cleaning to the next.
And then there's what water does when it freezes; our foundations have to go at least eighteen inches, ideally more, below the surface of the soil, so as to keep below the frostline. In the surface, organic soils, the moisture content is a high enough percentage of the total that when the ground freezes, it heaves out of shape. A fence or pillar or just a mailbox, let alone a foundation, that's too shallow or poorly grounded on sterile soil, can get pushed around by the movement of the earth when it gets frozen solid, then thaws, then comes together solid again.
Which is why we surround our buildings with drainage and subsurface channels to get the water away, so when it freezes it doesn't create more pressure against the house. Not to mention the year-round desire to keep water out of our basements, not to have even the damp in our holes in the ground, driving off mold and keeping away mildew.
This time of year, as we swing wildly from frost to warmth, from sleet to rain, Raccoon Creek flooding and the sprouting earth soggy, I think about those ancient Builders, the Native Americans who first settled and civilized these valleys and plateaus. How did they build their lean-tos in the woods, or construct pit houses on the bottomlands? From the fire hearth to the entry flap, what strategies did they employ to keep both cold and damp away from their families? What woven mats or interlaced branches gave them the ability to shed the spring rains and stay dry as they slept, on earthen benches or lashed cots off the ground?
