|Copyright 2013 Sippican Cottage. Don't be de-copyrighting this. I calls it. No erasies. Black magic. Eggsetera|
You axed for it; you got it: Sippican Cottage's Handy Guide To Engineering Your House.
Blecch. I hated using "engineering" as a verb in that sentence. But the Intertunnel verbs all sorts of nouns these days, because reasons. I'm just going along with the flow.
Back to the topic at hand. You want me to tell you how I lifted the back of my house and slipped a foundation under it, using a few hundred dollars and a teen-aged boy as my resource pool. I'm getting to it. But first you need an engineering course. I know you've been told that you need to go to school for twelve years, and then go to school for about six more years to build anything, but I'm here to tell you you don't. You need to understand that drawing at the top of this essay -- that's it. No, really; that's all there is to designing a house.
Let's go over the players before the curtain goes up. Here's where you come in. I hate to break this to you, and believe me, it's nothing personal, but it's my duty as your architect, teacher, and friend to inform you that you're the HEAVY THING. I know you've been staying away from the break room donuts, and running in the occasional 5K for breast cancer or whatever, but it's true. You're the weight in this concrete and plywood sandwich.
It's not just you, either. It's all your relatives, if you can convince them to come over for Thanksgiving, and all the chairs you'll be sitting on -- or if you invite me over for Thanksgiving, the recliner I'll be sleeping in. Your jugs of Chanel No. 5 and your cat litter box count, too, and equally, if they weigh the same. Anything that weighs anything in your house is part of that arrow.
On to the VAGUELY BENDY THING. That's generally your floor. Take no umbrage at your floor being described in this manner. I am not casting aspersions on your floor, because aspersions are heavy, and we'll have to include them in our calculations of the HEAVY THING, which will make the arithmetic more complicated. If you go down in your basement and look up, you'll see rows of bendy things, spaced as regularly as a high school dropout (probably a Mexican high-school drop out at that, these days) can space them. Those are floor joists. They're in the ceiling, because you're in the basement, but they're floor joists. Ceiling joists are what you see if you go in the attic and look down. I told you all this was simple, but I didn't say it wasn't goofy.
You have to remember now, that all those VAGUELY BENDY THINGS, no matter where they are, eventually have to be added to the HEAVY THING arrow. They're called "Dead Weight," or more precisely, "Dead Load." You and your fourteen cats and furniture that smells like you and fourteen cats is called "Live Load." It's not all that important to sort them out, and you can add it all together, Live and Dead load, and enter it all under HEAVY THING and not worry about calculating it to the last avoirdupois, unless you're running a Zumba class on pogo sticks for the clinically obese in your living room or something equally exotic. It's common to use numbers like 40 PSF for live, and 10 or 20 for dead load, depending on what you're building, and who's using it. Snow on the roof, and wind blowing against the side, and those five layers of roofing you left on my leaky roof, you bastards, are all loads that must be accounted for, too. So only build your house in the summer, and when it's not windy or rainy, and the arithmetic gets easier, unless you have to explain it to the building inspector.
Now, on to the CRUSHY THING, and its very important counterpart, the OTHER CRUSHY THING. Back when humans weren't all idiots, everything in a house was sorta symmetrical like THE CRUSHY THINGS. You went through a door, or a city gate, or in my case, the portal to the jailyard, and there was a lintel (the VAGUELY BENDY THING) plopped atop two CRUSHY THINGS. It looks sensible to a sane person. Before everything in interior trim became joined with 45 degree angles like a picture frame, all your doors and windows had a frame like that around it. It looks sensible, that's why it's beginning to look out of place in a home now.
Pay attention now: The CRUSHY THINGS on some levels of your house might be VAGUELY BENDY THINGS turned upright. Your exterior walls might be made from a whole bunch of 2x4s, and your second floor would sit on top of that. VAGUELY BENDY THINGS make lousy CRUSHY THINGS when you get right down to it, so you put a whole lot of them fairly close together, generally 16" apart, and put one horizontally on the bottom and two horizontally on the top, and then nail sheathing all over the outside of it, or if it's entirely inside the house, you screw drywall all over it. Then you nail the ever-loving hell out of it, and the resulting assembly makes a pretty good CRUSHY THING. If you watch Home and Garden television, these assembled CRUSHY THINGS are called "walls," generally the very walls the realtor says you can "just" demolish so you can have a clear, unobstructed view of your microwave from the other end of the house, and to allow you to hear the dishwasher running when you're trying to watch football, even though it's nearly sixty feet and two rooms away. Nota Bene: "Just" removing these CRUSHY THING partitions results in having all the VAGUELY BENDY THINGS and all the HEAVY THINGS land on your head.
Eventually, all the ad-hoc CRUSHY THINGS make their way down to sit atop the king of all CRUSHY THINGS, the foundation. That's usually a concrete affair, the only thing that keeps you from digging out under your lawn and the street to make one more room underground to watch TV in, even though there are four or five rooms to watch TV in your house already.
So the foundation holds in all the crazy, i.e.: you. It keeps out a lot of crazy, too. People think it should keep out water, but it can't, so your feet are sitting on a sopping carpet while you're watching that TV down there. It's not the concrete's fault. It's just supposed to keep out the very largest snakes, and withstand the entire weight of all the dirt outside from pushing your house flat from the sides like a soda can ready for recycling. It transfers all the force from all the HEAVY THINGS, and all the VAGUELY BENDY THINGS, and all the intermediate CRUSHY THINGS, then transfers all that to your footings, which are just more CRUSHY THINGS, lying horizontally under your foundation walls, transferring the weight of everything but your mortgage to Mother Earth -- which is supposed to be the ultimate CRUSHY THING. Like I said, it's supposed to, but your house probably sits on peat moss or mulch or mud or sand or ball bearings or some other unsuitable substance, because the man that digs the cellar hole knows he's going to be retired before you figure out what the hell's under your house.
If you don't have any sort of basement, and your floor is concrete, you've somehow been convinced to live in a basement that's located above ground, or maybe it's more of a garage where you're the car. This is called "slab on grade," or "Texas." Don't be fooled. The concrete floor is still the VAGUELY BENDY THING in this situation. That's why it cracks. It's trying to be a BENDY THING, but concrete doesn't care for bending, it only likes being a CRUSHY THING, so it breaks pretty easily.
Therein lies the lesson. Designing a house is simple. Look at the drawing again. I'm not joking, it's that straightforward. Figuring out all the forces involved, and then sizing all the VAGUELY BENDY THINGS and all the CRUSHY THINGS is as easy as looking up a few charts on the Intertunnel and walking down the derelict aisles at Home Depot, where they keep all the framing lumber and you can see all the VAGUELY BENDY THINGS on display.
My house? The HEAVY THINGS are way too heavy, The bends in the VAGUELY BENDY THINGS aren't vague at all, they're visible to the naked eye -- from space, I imagine-- and the CRUSHY THING it's all supposed to sit on has been crushed to powder and washed away. Let's see if we can restore it without us becoming CRUSHY THINGS by accident.