Editor’s note: This post is one of a series by Eric Whetzel about the design and construction of his house in Palatine, Illinois, a suburb of Chicago. The first blog in his series was called An Introduction to a New Passive House Project; a list of Eric’s previous posts appears below. For more details, see Eric’s blog, Kimchi & Kraut.
Floris Keverling Buisman, from 475 High Performance Building Supply, did our WUFI analysis and suggested the Intello would be a better fit for our project than Zip sheathing. Intello is a smart vapor retarder, so it can expand and contract as needed, and it’s obviously less physically demanding to install than Zip sheathing.
Once the air sealing was complete around the top of our outside perimeter walls, and the insulation chutes had been installed, we were almost ready for the Intello. At the gable ends of the house, one last detail needed to be put in place (circled in red in Image #2 at the bottom of the page).
Adding this 2×6 on the flat, which is in the same plane as the bottom of the roof trusses, makes it possible to carry the Intello over the transition from the ceiling (under the roof trusses) to the walls (top plates). This is one of those details that is hard to “see” when in the planning, more abstract, and two-dimensional phase of designing a structure.
Once the trusses were placed on the top of the walls and you start imagining how the Intello will be attached to the ceiling, it becomes much more obvious that something in this space at the gable ends of the house is needed in order to accomplish the transition from the ceiling to the walls.
Installation is easy — with some help
After reading about so many other projects that utilized Intello, it was exciting to unwrap the first box. The directions are pretty straightforward, and the product is relatively easy to install, as long as you don’t have to do it alone.
I didn’t get a chance to touch and feel the product before ordering (always fun to do with any new product). The front side, the side facing the living space, is shiny. The back has a matte finish. I was curious about its strength and tried to tear it with various objects, including the cut ends of 2x4s and the brackets we eventually used to help establish our service core. The material is surprisingly tear-resistant, but a utility knife, or a stray sharp edge will cut through it (as our first plumber proved to me with his careless actions — a story for another post).
Having never used the Intello before, I decided to start small and began by experimenting with it in a corner (see the image posted at the top of this blog). Getting the corners fully covered while getting the material to sit flat before applying the blue Tescon Vana tape proved to be the most challenging part of using the Intello.
In order to attach the Intello to the bottom of the roof trusses, we used the staple gun shown in Image #3 below. Loading it is kind of counterintuitive. (Online reviews complain about it not working out of the box, but my guess is — like me — they were trying to load it improperly.) Once I figured it out, it ended up working really well, almost never jamming, and it’s very comfortable to hold because it’s so light. It should work with any standard air compressor. It was available on Amazon and in Menards, a local big box store here in the Chicago suburbs.
Instead of loading from the bottom, like all the finish nailers I’ve ever used, the staples load higher up, where the staples exit. And yes, there was quite a bit of swearing as I made the transition from “What the…” to “Ohhhh, now I get it…”. It didn’t help that there were virtually no instructions on its use, apart from a tiny black sticker with an arrow pointing to where to load it (which, of course, I only noticed after figuring this out).
The heavy duty Arrow staples we ended up with seemed to grab better (presumably the sharp ends make a difference), and they sit flatter on a more consistent basis (less time having to go back, or stop, to hammer home proud staples flat).
Getting the hang of it right on time
As we rolled out the Intello, it took some practice to get it to sit taut and flat before stapling.
The dotted lines near the edges of the Intello (see Image #4 below) help you keep the rows straight as you overlap two sheets and progress from one row to the next. The lines also make it easier to maintain a straight line with the Tescon Vana tape (don’t ask me when I realized this latter detail — too embarrassing to admit).
Working our way through the interior walls, especially the bathrooms, was more time-consuming and took more effort. (I grew to hate those interior bathroom walls — first the Intello, then the service core details described below.) But once we were out in the open, the Intello was fairly easy to install.
As Eduardo and Jesus rolled out sections of the Intello, I followed, pulling on the Intello a little to help make it sit tight and flat, before stapling. There were a couple of sections, some of the first ones we installed, that I managed to wrinkle (one, in particular, became problematic during our first blower door test — and, of course, it was in a tight spot around the bathroom shower area), but overall, the installation of the Intello went pretty well. Like most things you do for the first time, we got comfortable and good at it just as we were finishing up.
We decided to use Tescon Vana tape to cover the staples, as well as all the seams, in the Intello. I have no idea what actual impact covering the staples has on airtightness, but visually as you tape over the staples you can see how, if nothing else, it will help the staples resist pulling out under pressure from the eventual blown-in cellulose in the attic.
Even as the build progresses, it’s interesting how details like this pop up, making building “green” a never-ending process of learning something new — someone’s always coming up with a new product or a new way to do things better, faster, or less complicated — which makes the process itself very exciting.