Friday, November 22, 2013

Sippican Cottage's Handy Guide To Engineering Your House

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.

20 comments:

benjaminthomas said...

You have a gift -- not just for writing, but for 'splaining. You just taught more engineering in a few paragraphs than most 200 level university courses provide.

No wonder your homeschool is rated #1 in the USA.

Reminds me of calculus as a college freshman. First professor had a passel of degrees and a paucity of common sense. I ended the semester dumber than I started it (and that's saying something). Second semester, I stayed after class to ask the TA to "clarify" a remedial point I should have learned in the first week of the previous semester. He explained it all to me in terms like CRUSHY and BENDY and I suddenly understood more about calculus than I did in the first four months.

-benjaminthomas (currently residing in Dallas, Slab On Grade)

Matt said...

So, this couch cushion is getting less bendy...

leelu said...

...California, too. I had both the hot and cold water feeds die under the slab foundation of my last condo out there. The hot leak was signaled by a nice warm spot in the kitchen floor. The cold leak announced itself one morning when I walked from the stairs to the kitchen, and the footstep sound effect went from "Thup, thup, thup", to "Squish, squish, squish... ."

vanderleun said...

Whatever you do, don't eat the thin mint.

http://www.youtube.com/watch?v=HJZPzQESq_0

Leslie said...

There are no basements older than 40 years in my town, as the ground beneath our houses is called caliche. Until enterprising folks with big machines got involved, we just stayed above the ground. I have a block, with plaster on wire lathe, house that sits on a slab on grade. If it gets really cold in the desert, our concrete foundation moves all around, popping up the tile. Big fun. Luckily, there are no spiders under the tile.

Anonymous said...

But Reginald, it's only wafer thin...

joated said...

I'm finding your essays more and more entertaining AND informative with every new entry.

I've a cabin/shack in the Adirondacks in sad need of a new foundation or a wall or two thereof so I'm waiting with baited breath the lesson you are soon (hopefully) about to impart.

Leon said...

yea ben i'm in the metroplex too.
i wish i had slab on grade...i have small chunks of concrete on grade which someone laughably called piers, and no beams at all just slightly bendy things and floor...no subfloor either. on the up side the water's easy to get to when it lets loose.

Anonymous said...

Looking forward to the strngth of materials section, with emphasis on pine knot quality divination...

sorry for the missing " " & " ", keys on occasion retire early.

Anonymous said...

Thank you. Well explained and well written. I love this kinda stuff. I'm in the Southwestern World of adobe on stem-wall on footer with brick pavers on sand floors; amazing to have such different construction in the same country. It doesn't rain much here and wood lasts about six months. Bravo.

Cambias said...

Foundations? What a curious concept! My parents' house in New Orleans (and all the other houses that didn't become tear-downs when the city flooded) was built three feet off the ground on brick pilings.

The concept of a level floor was something of a shock to me when I visited other parts of the country.

Anonymous said...

I'll just mention, and sorry about that and all, that when you "go with the flow" you are, by definition, headed downhill.

Kat in Indiana said...

Actually had my two XY's laughing when I read this to them, event though they had to turn the sound down on Minecraft and Call of Duty to listen. Our money pit has slab, crawlspace, cellar AND sometimes-a-swimming-pool "finished" basement. Most of the Bendy Things were installed in the last round of 'teens, some in the 30's, some in the 50's when the upper Crushy Things burnt off, some in the 90's....many other Adventures in Old Home Ownership. Can so thoroughly feel your pain!

Sam L. said...

Ah spect a bendy floor be a more comfortable thang to walk on than concrete. Easier on the carpet wear, fer them wearin' carpet.

My granddaddy, he built his new house by himself, way back when. Not an engineer, not even on the railroad.

And them aspersions, they's messy when they hit sumthin.

Them crushy walls 'minds me of a Fawlty Towers episode where Basil had the O'Reilly men tear out a load-bearing wall.



Anonymous said...

I love this series. The only exam I actually remember in detail is the Engineer In Training exam.

The PE exam sort of, the Contractor's exam, barely. The EIT exam was akin to finding out you might no longer need the training wheels on your bike.

One of the people who taught me the way summed it up rather succinctly, "you just might know which end of the candle to try to light."

Best,
Allen

leelu said...

Sip,

I gotta say, the comments (minus this one, of course) are almost, but not quite, as entertaining as your original posts.

Easter next??

julie said...

I saw this video over at Neatorama, and it seemed rather apropos. I would suggest it for the Borderline blog, but it lacks that "hold my vodka" quality...

BillH said...

Julie - Great vid link. Reminds me of how we did things when I worked in my Dad's greenhouses in the '40s. I still use the same techniques - when you're in your 80's, leverage is critical when you're trying to lift/pull/push/hang/suspend something heavy by yourself .

Larry Geiger said...

“Therefore everyone who hears these words of mine and puts them into practice is like a wise man who built his house on the rock. The rain came down, the streams rose, and the winds blew and beat against that house; yet it did not fall, because it had its foundation on the rock. But everyone who hears these words of mine and does not put them into practice is like a foolish man who built his house on sand. The rain came down, the streams rose, and the winds blew and beat against that house, and it fell with a great crash.”

So everyone who lives in Florida would not be like the wise man. I live in Florida. On grade. Two to three feet below my feet lies the water table. No basements here. The only thing under my slab is sand. For hundreds, maybe thousands of feet down. What's not sand is porous limerock and coquina, which is really just sand just starting out on the rock phase.

When the pipes in the slab corrode through then you need an entirely new water distribution system that comes through the attic. Sheetrock must be demolished to install the new pipes. It's sort of like getting a whole new house but with an existing foundation run through with empty, corroding pipes and bugs. Oh well, it rained last night and it stayed dry in here so that's good.

marvo said...

Sadly older houses are not necessarily better. Mine is at least 1890 (dated lease document) but I think it might be 1770 (map with a house in the same place and a front door with a retrofit letter slot). The whole place is jerrybuilt. Foundations are next to nonexistent which is fine as it is on sand and gravel of the London flood plain so quite solid. But the vaugely bendy thing (6m joists) hold up an post build brick wall and have sagged. Someone added extra support but did not measure correctly and the extra support is a foot and a half away from being under the wall it is trying to support. Still it has not all fallen into the basement in ten years of me living here.