Fastener Frustrations

Jeremy just posted on Facebook something that I think pretty well sums up the frustration I've been feeling today: "...construction in the United States is the dumbest shit ever. penny nails? 8d? cause labeling by length and diameter would be too hard..."

Let's take a step back and give some background information. Jeremy and I have been talking about doing at least some posts that delve into the more technical aspects of our design and construction process. If you're only interested in pictures of walls and such, of course feel free to skip such posts :) However, I have felt that, in the community of tiny house blogs, there is a overwhelming ratio of fluff content to useful technical content. Don't get me wrong, I love perusing the likes of tiny house swoon, which (and I hope nobody takes this too harshly) amounts to little more than "house porn."

I recall when researching how to size solar systems, I found literally dozens of posts on tiny house blogs with vague references to eventual plans to maybe install something because it's, like, good for the environment or something. In contrast, I think I found only one post that really delved into this is how many Watt-hours I expect each of my devices to use per week and this is how we calculated the expected actual performance of our panels versus their rated maximum capacity. If I can contribute even one such substantive post, and have it read by just one person trying to puzzle out that aspect of their build in the future, this will have been a worthwhile endeavor. Even if not, documenting my own thought processes should help me keep straight why I reached certain decisions, so I don't waste time second-guessing myself later.

Okay, so with that aside let's jump back into fastener sizes. I'm going to be installing boards over my rafters soon. These boards are 60mm (almost 2.5 inches) thick, compared with the "normal" sheathing board that goes over rafters of half or three-quarters of an inch (that's 13-19mm, to help you compare apples to apples). There are numerous advantages to the boards I've chosen, but this post is on fasteners; maybe I'll do a technical dive post on Gutex later.

Thin OSB or plywood sheathing boards can just be nailed or screwed with 2" fasteners: readily-available in U.S. big box stores. But Gutex installation instructions specify "180mm x 6mm" nails, and then have a chart for how many you need per meter, depending on what your roofing material weight and snow load are expected to be, in kN/m^2. I can picture your eyes glazing over about now, reader, but just try and bear with me! The German manufacturer means everything is in SI units, but you'd think: "That's fine, I'll just convert millimeters to inches, viola!" No such luck though: in the U.S., nails are measured in penny size. So, just look up the converted size in the chart, right? (meanwhile, try to shrug off the annoyance that an "8d" is not 50% the size of a "16d", but rather ~71% of the size) Not so fast though: wikipedia is a great place to start, as always, but the whole picture is way more complex. Is the penny size really a measure of length? Well, only sort of. A 16d is usually used for framing, but contrary to the table showing it as 3.5 inches, it could be 3. Or 3.25. The ones we used with my borrowed framing nail gun are both marked 16d, and only 3 inches long. The nails we're using for hurricane clips are marked 8d, but are only 1.5 inches, not 2.5. And these are but two examples in a sea of inconsistency. Why all the discrepancies? Well, when you come down to it, the penny size system is not a system at all, it's a hodgepodge of historical holdovers. Nobody at any point was able to get universal acceptance of a conversion from penny size to an actual unit of length.

And we haven't even started in on the diameter of the nails (the short story there is that those are even less standardized).

Okay, so maybe it's just easier to order some nails in metric size from a German manufacturer? Nice try, but good luck doing so without being fluent in German. Maybe from the U.K. then? Then, all you have to worry about is shipping. Oops, that's not a small issue either. The fact is that, like most industries in the U.S., fasteners are dominated by very few players. In fact, it only takes a few minutes in the right aisle to realize that more than 80% of all nails and screws at both Home Depot and Lowes are all made by the same manufacturer (I'm talking about you, Grip-Rite). Do you think that manufacturer makes things in SI sizes? Not a chance. Like everything else in the world of construction I've come across, the supply chain in the U.S. is great...as long as you toe the line and buy exactly what everyone else is buying from your (not-so-)friendly (not-so-)local store, supplied by the monopoly-holding manufacturer of that type of widget. Deviate at your own risk.

For that one future builder out there struggling to install 60mm Gutex boards in the United States, here's the best answer I could come to. Look for 60d nails: that's about the longest you'll find here (still not as long as recommended, but it will have to do). And when you find those 60d nails, look for ones that are as close as possible to "4 gauge" diameter, which could also be variously written #4, 4ga, 4AWG, and any other number of nonstandard infuriating forms. To convert that to a meaningful unit of length, you're aiming for about 0.2 inches. Was just making and selling a "6 inch by 0.2 inch nail" so hard?