Hell is other truss connectors

December 18, 2024 12:35 PM

The Invention that Accidentally Made McMansions. Architecture youtuber Stewart Hicks breaks down how a simple invention you've probably never heard of transformed the American residential landscape.
posted by theodolite (23 comments total)

Obligatory: can't truss it
posted by thecjm at 12:48 PM on December 18 [2 favorites]

This is a pretty good video, though I think Hicks kind of underplays ongoing trends in suburbia to emphasize the impact of the metal bracket. Sears was selling kit houses a century ago, so assembly line homes were not necessarily a novel idea and the suburbs in general, such as Levitt Towns, also introduced the anti-environmental idea of plastering house after house after house and so on in a way that was harmful. The bracket really just opened up more opportunities for bad architecture, taking useful space in one part of house (i.e., the attic) and transferring it to elsewhere (open spaces and high ceilings).
posted by Atreides at 1:04 PM on December 18 [8 favorites]

i know more about truss connector plates than you can possibly imagine.

i was a industrial carpenter for almost a decade, assembling the component pieces of southern yellow pine in a jig, hammering them together with nails and truss plates before running over the assembly with a big dangerous roller before sending out through a finish roller in the side of the building.

plates are sharp but after a while you learn how to grab them so they almost never cut you.

the most useful life skill i learned from this was being able to accurately estimate the size of anything from 2 to 16 inches because that's the range of size the plates came in and you had to be able to tell at a glance what plate went where, especially in the final inspection role which i also performed, where you look over the entire truss outside in the stacking yard and note any missing plates before stopping the production line to fix a missing plate and run it back through the finish roller. 2"x3", 3"x5", 3"x6", 5"x5", and 5"x6" were the most commonly used.

i was especially good at deconstructing broken or mis-built trusses. i had to have a certain hammer (a Estwing 20oz straight-claw) but i could stand over the finished trusses lying flat on the ground and swing the hammer, claw-forward, and get the claws right in between the steel truss plate and the wood in order to pop the edge of the plate off and pry the now-ruined plate away. depending on the damage or design error the truss could be repaired or reused. with luck i could get a 3x5 off in two or 3 hammer swings.

[CONTENT WARNING: bodily injury] once while i was at work a man lost his leg to impatience. where the truss went through the finish roller was also the walking path to access the other side of the production facility. you would stand there and wait for the truss to go through before crossing. this man was impatient, always, and would sometimes put his hand on the truss and vault over it while it was in the grip of the finish roller. one time he missed his vault and his leg slipped inside the truss. that was all she wrote. luckily someone else was standing right there to hit the e-stop bar so only his lower leg below the knee got crushed. [/CW]

that time was a crazy time in my life. i was a punk rock teenager/young adult working my way through community college. almost everyone who worked there was on drugs almost all of the time. we were extremely underpaid and expendable. our supervisor would occasionally send someone out to the parking lot to clean up all the malt liquor and beer cans and sweep the blunt guts into the gutter. we would use our 30 minute dinner breaks to race to the store buy beer and blunts, then roll up while we were going through the Hardee's drive-through getting big sacks of $1 double cheeseburgers. the beers and blunts were consumed on break, then we'd eat the cheeseburgers at the production table when we got back to the night shift. the unofficial company motto was "it ain't nothin' but a party."

the owner of the place was a notorious coke head. when he was especially jacked up this millionaire would walk around the plant bumming cigarettes from the minimum-wage workers and generally being a total ass to everyone and talking crazy shit. he also cheated on his wife with his nextdoor neighbor, who's husband committed suicide when the affair became known. many of my coworkers were strung out on crack, and were deeply in debt to the owner by getting paycheck advances right up to whatever the limit was.

i don't miss it, but i'm glad i got to experience some of it, although i wish it hadn't taken up as much of my life as it turned out taking. this was all in the 1990s. i hear the place is all cleaned up now (except for the owner) and all the crazy shit we used to do has been stamped out, thankfully.
posted by glonous keming at 1:09 PM on December 18 [101 favorites]

Over the pandemic we watched a bunch of the UK homebuilding show Grand Designs. One thing that struck me was the use of structural insulated panels (SIPs), a foam-and-plywood sandwich product that replaces the need for wooden framing altogether. Many of the builders featured on the show designed their homes, had the SIPs made at an offsite factory, and got them trucked in and assembled with a relatively simple crane and fastener process.

I’ve not seen those here in the US but they feel like they could influence home design the same way that cheaper trusses did in this video. Sometimes the builders would use SIPs to produce a small building more quickly than they would otherwise, other times they’d use them to stay within budget on a much larger than they could otherwise.
posted by migurski at 1:14 PM on December 18 [6 favorites]

I flagged your comment as fantastic, glonous keming. Thanks for sharing.
posted by ishmael at 1:23 PM on December 18 [4 favorites]

When I built a modest shed in my backyard I made my own roof trusses on the ground using cut pieces of plywood instead of the metal plates. Much easier than trying to frame the roof on the shed directly. I could make the trusses myself and then just needed a hand keeping them upright until I was able to attach them to the shed walls.
posted by any portmanteau in a storm at 1:28 PM on December 18 [2 favorites]

He goes off the rails around 7:30 with the claim that roof trusses in 2-story houses facilitate totally open plans on the first floor. They do not. Load-bearing partitions help carry the the weight of the floor above, but not (typically) the weight of the roof, regardless of whether trusses are used.
posted by jon1270 at 2:18 PM on December 18 [4 favorites]

I think the case that these 'created' mcmansions is wildly overstated. IMO, home builders building homes for the people who lived there (women and children) instead of the 'man' of the household, who spent most of the day gone elsewhere, is by far the biggest factor.

Customer satisfaction and surveys were also products of this timeframe. Go to any suburban house - what's the biggest room? The living room, the one the 'man of the house' spends most of his time in. Kids bedrooms, the kitchen, and storage were all afterthoughts. They didn't invent the shower niche until the 2000s! Nobody designing homes gave a crap that women used more than 1 bottle of soap or shampoo before that! Think about that.

And yeah, those of us who were alive then did share space - but it was tight and honestly it kind of sucked. I'd not choose to live like that again to save a few bucks.

Also he's wrong about attics. A trussed attic is a far more palatable place to work than a 4/12 which is a common '50s-'80s roof pitch, and (I think) featured on his Miami ranch example. Getting A/C ducting and other stuff commonly constructed in attics royally sucks. That was also a a major factor.

You have to go back way farther than the 1950s to where the attic was essentially a room.
posted by The_Vegetables at 2:19 PM on December 18 [4 favorites]

Also, he never really explains why complicated roof designs came into play, also way before trusses: because they seem more fancy that a single pitched home, which kind of look like trailerhomes. They also really need a good exterior design and far more expensive porches to look nice.

I mean if trusses save money, then wouldn't they enable simpler roof designs to lower the total construction cost of the home (not sales, price, construction cost)? Yes, unless there was some other factor, which is customer preference.
posted by The_Vegetables at 2:23 PM on December 18 [1 favorite]

I don’t have time to research it right now but I am suspicious advances in lumber cultivation (that yellow pine glonous keming mentioned in their fantastic comment) was another big factor influencing 20th century home construction in the US.
posted by TedW at 2:41 PM on December 18 [1 favorite]

migurski: "I’ve not seen those here in the US but they feel like they could influence home design the same way that cheaper trusses did in this video."

SIPs are a brilliant building material, and yes, they've been around in the USA for a while. I've got an architect friend who built a house with them almost 20 years ago.
posted by adamrice at 2:43 PM on December 18 [3 favorites]

When I built my workshop I called up a few SIP manufacturers, but I had particular engineering requirements (living roof built for 120lbs/sq.ft.) and none of them would give me anything more than "talk with your local building authority".

But when I called up the local truss place* and said "120 lbs/sq.ft, two in twelve" they said "You're sure? Right, let us put that into the software... okay" and that's what they gave me, engineering stamps and all.

So I suspect that the spreadsheet was as much a part of the truss manufacturing innovation as the connector plate.

* I'm assuming the local truss place is pretty much exactly what glonus keming described, because after a few weeks of no contact I got to the point in construction where I couldn't go any further, drove out because nobody was answering my phone calls and they said "oh, yeah, good thing you caught us, we were gonna go on vacation this afternoon, the trusses are right there.... oh, yeah, right, we were gonna deliver them...".)
posted by straw at 3:33 PM on December 18 [14 favorites]

A system that can combine glonus keming's described batshittery and turn out reliable trusses to a novel engineering specification is a heck of a system. (Has your workshop roof survived long with the heavy roof? i guess is the verification question.)
posted by clew at 3:41 PM on December 18 [3 favorites]

I recently put a pull down ladder and plywood up in the attic of my 1925 Craftsman house and the roof up there is wildly expansive. Nearly enough to turn into a little room, but just a bit too short anywhere except in the middle. But all that old dense fir up there. Nice to see.

Also, really surprised that in FL's rush to be as business and developer friendly as possible they haven't gutted the codes that got reinforced after Hurricane Andrew
posted by drewbage1847 at 3:51 PM on December 18 [2 favorites]

I worked in a place like that, glonus keming, in Phoenix in the late '70's. I only lasted a summer because my life was a wreck and I was doing more drugs than anyone else (maybe) and after a while just stopped showing up. I think Phoenix at the time was at the forefront of prefab construction and whole neighborhoods would go up in a week. Sorry I don't have any numbers to back this up so you can choose not to believe. Anyway, it always surprised me later, living in other places when I didn't see people using this method. Happy holidays everybody.
posted by evilDoug at 3:55 PM on December 18 [3 favorites]

Also, he never really explains why complicated roof designs came into play, also way before trusses: because they seem more fancy that a single pitched home, which kind of look like trailerhomes.

But before trusses, hipped roofs were much more common. I understood that it was only after the introduction of trusses that the cost difference between a hipped roof and a gabled roof became much more significant (because of the labour costs) and gabled roofs became the dominant style for regular homes.

I don’t have time to research it right now but I am suspicious advances in lumber cultivation (that yellow pine glonous keming mentioned in their fantastic comment) was another big factor influencing 20th century home construction in the US.

Running out of tall, straight old-growth softwood lumber as we started to log replanted, second growth or just generally smaller-treed forests resulted in the switch from balloon framing (where you used two story tall 2x4s for a two story house) to platform framing (where every floor has its own stud walls). The introduction of platform framing had a big influence on home design and allowed for a lot more flexibility.
posted by ssg at 4:17 PM on December 18 [6 favorites]

Platform framing is also safer in a fire that starts in a wall cavity, as there is built-in fire-blocking hopefully slowing down the spread of fire upwards.

Good video, but as noted above unless your entire second floor is built of engineered floor trusses or possibly glue-lam beams of the right size, you don't get to have and entirely open ground floor, a typical house is going to be 24' deep (or possibly more) and single-piece lumber to span that width is quite large and heavy and more importantly has all been used up already. Typical 2x8 joists will span about 8 or 10 feet, as I recall.

(If you're in the Capitol Hill area of Seattle and want to see how big timbers can (and used to) be, have a beer at the Elysian Brewery on Pike. As I recall, the building is the old Packard dealership and the second floor was built for automobile traffic. The restaurant is on the ground floor, so you're staring up at massive timbers we'll never see the like of again.)
posted by maxwelton at 5:33 PM on December 18 [8 favorites]

I don't agree that trusses caused McMansions at all. They certainly made basic roofs much quicker and cheaper to install, but have a much lower impact on the complicated roofs that are a dominating feature of such houses. This is because multiple roof planes require a lot of manual cutting and installing of timbers in addition to the trusses, whereas a simple gabled roof is extremely quick and cheap to install using trusses.

It's also not correct that trusses always carry the roof load via external walls only. They can, if designed to do so, but it's normal for one or more walls to support the trusses mid-span so the truss can be lighter (and cheaper). In any case, he points out that modern homes often have large open spaces on the ground floor and a lot more dividing walls on the first floor. So the roof trusses are not supporting those open spaces, with the floor usually being supported by either floor trusses or laminated timber or steel beams. Such houses still have one or more structural walls in the ground floor that serve to help support the floor above and, in turn the roof trusses.

What caused McMansions, then? People with outsized egos and banks stupid enough to let people get way over their heads in debt. it really is as simple as that. People caused McMansions in the same way they caused nearly every stupid thing we have today.
posted by dg at 7:15 PM on December 18 [6 favorites]

But before trusses, hipped roofs were much more common.

Nah. Hipped roofs are common on ranches, which were a very common post-war style, but in general? Boatloads of gabled house existed prior to trusses. I think it might seem that way because a hip roofed ranch was a dominating mass building style across the US for such a long time.


What caused McMansions, then? People with outsized egos and banks stupid enough to let people get way over their heads in debt. it really is as simple as that

This. There are streets where they build low-slung ranches in the '80s, and then the style changed to mcmansions mid-block. The switch was that abrupt.
posted by The_Vegetables at 7:21 AM on December 19 [1 favorite]

It was interesting to learn the history of the truss plate but it seems a stretch to blame McMansions on it anymore than you'd blame them on nailguns and plywood. I can't remember the name of the paradox that an 18th century economist described (Jennings? Jenwood?) whereby when efficiency goes up consumption goes up, ("I've got led lightbulbs now so I just leave the light in the closet on all the time!,") but the steady expansion in house size strikes me as an example. It is one of the reasons I take the passion for 3-d printed homes with a bit of skepticism. For sure the ability to frame a roof with a gazillion gables for a fraction of the cost it would be if it were hand cut has an effect but then so does undocumented 1099 labor, drywall, power tools, plywood etc. etc. not to mention structured assets Fannie Mae, mortgage insurance etc. etc.
posted by Pembquist at 9:03 AM on December 19 [3 favorites]

Without trusses, McMansions would still exist, except that they wouldn’t look like they do now, especially their absurd rooflines.
posted by 1970s Antihero at 11:39 AM on December 19

Pembquist, I think you mean Jevons Paradox.
posted by any portmanteau in a storm at 12:50 PM on December 19

But before trusses, hipped roofs were much more common.
Nah. Hipped roofs are common on ranches, which were a very common post-war style, but in general?
Depends where you live, I guess. In Australia and New Zealand, a gabled roof has long been considered a low-end roof style because it's the cheapest to build using trusses, where a hip roof or similar creates a more pleasing roofline, but comes at a labour cost. Before trusses were available, the amount of work required to frame and cover a roof was so high that the style didn't influence cost as much.
posted by dg at 1:23 PM on December 19