With a little struggling I got my first piece on, and braced it with inward pressure to cure the adhesive. In most cases, holding pressure was obtained by simply tilting one of my brilliant white cinderblocks up slightly with its back corner retained by friction, and sending that force compressively through some member of an appropriate length to reach the wall where pressure was then spread out across the adhesion points on the insulation piece. In other words, any temporary crock-up of weight and pieces of wood that would work to push the panel against the wall -- and slightly upward if possible. I also reached down and squidged a little more dirt in under the bricks to increase their upward force before leaving everything alone to set. |
The Mighty Homebuilt Dirt-Tamper of Doom emerged once again, and was the perfect width to get down into these trenches to compact the backfill. I did this in incremental layers, to ensure best uniform density all the way up, and managed to not ding up the face of the Roxul too much with mis-aimed hits. This might have been the only part that would have annoyed the neighbors, as the soil hereabouts is fairly resonant when impacted. Thump, thump, thump, thump thump ... thump, thump. Thump, thump, thump thump thump thump thump thump ... thump, thump ... |
A short time later she'd made significant progress and kept things very tidy, producing a perfect-width trench. It's nice to have clueful friends who like pitching in on physical work! |
My helper, a biologist/naturalist by trade and avocation, had noticed several small conical pits in the very dry soil next to the wall and thought they might have been made by ant lions. We both found this odd, thinking that ant lions are more a southern thing, but we dug up a little dirt around some pits and managed to isolate the critters onto a piece of window screen and sure enough, that's what they were. These are actually ant lion larvae, also called doodlebugs. The adults have wings and look more like small damsel-flies living above ground, but the typical notion we have from guidebook pictures of ant lions is of these terrifying monsters with huge pincers that pop up out of the ground to grab their prey like the sandworms from Dune or Jedi. In fact they're quite small, and move mostly backwards with an odd humpy jerking motion that helps them dig and form the trap pits. | |
They were hard to photograph because they kept doing this rapid jerking
in an effort to dig through the window-screen and get away from us -- one's
in mid-motion here, and I managed to catch the other while still.
They'd just collided butt-to-butt like little bumper cars.
She spent a few minutes finding some small ants to drop into the
undisturbed pits and feed the ant lions, amused by how fast the victims
would get sucked in and captured. Mmmmm, crunchy goodness!
There are quite a few videos of this searchable on youtube.
The fact that numerous ant lions now reside in the soil next to the house is excellent testimony to just how *dry* that soil became since the renovation. It's really like dirt from the desert -- fairly loose, doesn't pack down very well since there's very little moisture content to help bind it. A clear result from having larger eaves and better drainage, plus the somewhat "mushroom" aspect of how far the above-ground walls and flashing metal overhang the foundation and nearby grade. With the addition of the Roxul it would become a couple of inches less mushroom-like, but I was still counting on those features for good long-term protection against rain. |
Because any removeable sections would fit back in rather tightly, I needed a reliable way to be *able* to remove them again, however infrequently, without mangling the insert pieces all to crap with external tools. A couple of screws through from the back of the small test-patch piece with washers on the backside had sufficed for that instance, but I didn't really want rigid screw points sticking out of the wall here and there being physical hazards not to mention unnecessary thermal bridges. Instead, small lengths of nylon string were turned into pull handles connected to load-spreading anchors on the back. The strings were separated halves of the otherwise mostly useless poi-leash bridles that had come with the glow balls I had ordered, and already had convenient little tee-shaped anchors attached, which could then go through little flat bits of plastic and get taped in. Close-fitting holes were then punched through the Roxul piece to tease the strings through and the whole assembly tacked down with adhesive from the back, and there were my pull handles. |
The section with the exhaust duct brought me around that back corner
from the stoop up to the bulkhead, completing two sides of the
house but for some remaining footing details and backfill behind
the stoop itself.
After that I moved to the opposite corner that my helper and I
had reached before, and continuing down the west wall was pretty much
plug-n-chug with "fullies" and a couple of simple window-port cutouts.
And the grade kept getting a little lower along that whole run, making the
digging easier as I went along.
I still went slowly and carefully and let the applied pieces set their
adhesive for generous amounts of time, and spent a while extracting
many of the rocks out of the backfill to store separately for later.
I had to break off for a weekend to do my usual infrastructure duties at the local haunt event, but was right back to it as soon as that was over. |
The home stretch
The slope of that edge was odd because here I was over the re-exposed underground gutter, and couldn't conveniently brick up underneath the Roxul. Instead, a couple of kludgey lever arrangements with counterweights held the bottom edge upward, along with the usual inward push. The piece came down just over the foil-tape lip of the flashing piece, which was not at the full 3-foot depth level, so had to be cut to conform. |
The updated intent was that the grade surface itself should drain off
most incident water that landed here. 
To that end as things went back together I wound up nesting in a largish
flagstone right under the downspout elbow, sloped away, and moving the
support under the extender a little farther out.
That way any random leakage from the elbow would flow away on the surface,
and only in total downspout failure and heavy rain would I expect enough
washout of the soil cover that the gutter would become really relevant.
This Roxul piece represented the first of several compromises on installation depth, not going down the full three feet from the sill. But it was all along the south wall, which actually gets some solar energy in the winter so this was of less concern than the other sides. The next piece on after this reached up to the old test patch, or what remained of it after I cut off part of the XPS foam that had managed to detach from the wall anyway. I left most of the patch in place and simply skipped over it, and that certainly doesn't go down to full depth either. It was okay, I didn't see this as losing a whole lot of relative effectiveness given that the really cold parts of the wall were all covered anyway. And I'd still have my little openable observation port with the pull-screws. |
For installation I had to accomodate the big rock that stayed in place almost touching the wall, but could put most of the cut-out piece right back in once it was set. |
And the *last two* exterior pieces finally went on!
I was almost done, and with this the really grubby parts of the
job were close to over with.
The truck-tire prints on the larger board were come by honestly. |
For something of a hack, this had been a *huge* amount of work from the
planning and acquisition phases on down, and there were still a few more
details to chase.
While I *was* using latex gloves for some of the fiberglass handling,
there had been lots of manual digging and rock-moving and surface-grading
and my hands were totally beat to crap and covered with flecks of adhesive
and wood-hardener.
But that which does not kill me, etc etc. I enjoyed the bit of
exercise not to mention the sense of accomplishment at actually being
able to pull off the job before cold weather really arrived, and generally
in a fairly elegant and workmanlike fashion.
I really don't think I could have gotten any contractor to apply quite the same attention to detail or building-science principles to something like this, especially laboring under the possibility that the experiment might not work out entirely as hoped and they'd be called back to try and fix it somehow, so a project like this may not be for everyone. My neighbor to the west seemed pretty amused all the activity, and asked the pointed question "do you think it's worth it?" From his viewpoint, that being purely financial, that's rather squishy. Let's super-optimistically say that if the project could cut the already modest $200-per-winter heating bill by a third, my materials costs alone would put the added "payback period" at around ten years and that's not including any of my labor. And with this new twist in the ongoing energy-improvements I was still looking at another couple of years collecting updated energy stats to see how much difference it would make. But really, the pride of designing and solving the challenges and getting it done [mostly] myself and the raw geek-factor involved are significant parts of the value here. And my cold walls were now a little better frost-protected, which certainly couldn't hurt. |
At this point I had an impressive pile of cuttings, plain and fancy. Adapting to the various features usually involved measuring outside and then cutting inside here, and I was glad that all worked out without any major foul-ups to cause material waste. The roadcases for my 918s had gotten commandeered and lashed together against a lally column as my cutting table, covered with one of the Roxul wrappers. This entire corner was a festival of fiberglass shards by now, and cleanup after everything was done took a while. |
A couple of months later, the first winter for this experiment was fairly mild in general but did bring a week of single and subzero digits -- nothing like the ice dam festival from the previous year, but still a good solid run of frigid. The soft dirt around the walls did a rather weird frost-heaving pattern, fluffing up about an inch above its packed-down level and working open a gap away from the Roxul surface. The soil right next to the house had always done that to a small extent, but now with the exterior of the wall so much colder there was nothing to warm that dirt up any more so any moisture trapped in it received the full influence of ice crystal expansion, trying to build its own little pingo. | |
The Roxul never felt soggy, though, other than in a couple of the horizontal "flange" pieces like near the side stoop and only in rain or snow melt when everything was wet. The spaces between the operable basement windows and the Roxul filler pieces over them never got unreasonably damp, either -- basically just tracked the outdoor humidity as always, so the Roxul's drying profile clearly remained wide open and it didn't appear to be accumulating any water. |
So, any profound results??
The block wall, as observed behind the removable outdoor test-patch,
remained safely above freezing the whole time, maybe high thirties to
40 in the coldest dips. The lowest I measured at the inside surface of
the cinderblock was 44F.
So the wall itself still showed a slight gradient, but was now unlikely
to ever see real freezing temps on the outside again.
Loss reduction aside, that's generally better for concrete.
As described in part 27, my data generally gets reduced to terms of whole-house BTU/hr per degree F of base-65 delta, said delta taken from averaging HDD figures from the two nearest airport weather stations listed at Wunderground [KLWM and KBED]. The conversion is still a bit complex, taking plug-loads and body heat and ventilation loss into account as well and after some testing, a variable heat-pump COP factor based on ambient temperature. Data collection is made even more complex on occasion by running on the strip heat instead of the heat pump to try and nail down the actual running COP under similar conditions. The script to reduce all this from midnight meter reads continues to get uglier and uglier, but is reasonably accurate in its calculations after several tweaks over the years. The basement with its uninsulated slab still represents the major nonlinearity when comparing energy use vs. heating degree-days, but on average the Roxul job coupled with some improvements around all the windows did visibly lower the average consumption over time. Mid-level basement winter temperatures ran about 4 degrees higher on average, from 56 in previous years to right around 60F this winter. That's still against a setpoint of 68F for the rest of the house, so that 8 or 9 degree delta through a maybe R-2 first floor with partial carpeting is still a significant part of the loss path and it never changes!. [One possible way to really *fix* the basement would be a fully insulated sub-floor, which may happen someday but is way into diminishing-returns territory and not on any near-term agenda at this point.] All told, observed average whole-house loss went from about 185 - 190 BTU/hr/F just post-reno to more like 155 - 160 BTU/hr/F due to various improvements over time. Not a huge step change after just the Roxul alone, perhaps, but overall trends which must be observed over a season-to-season basis simply because it's helping to slow heat loss from all the foundation mass and the dirt under the house. All that mass still wants to stay at 52 degrees or so during the winter, which means that heating the rest of the house normally is always "pulling" against that sink to some extent. Thus the colder it gets, the *lower* my HDD-based loss figures appear to run, and that's in spite of the cold-temps "polyiso U-factor hockey stick". There's also a phase-lag effect from multi-day trends in outdoor temp which again dictates longer-term averaging. [The basement factor is also most likely why I no longer need to do any real *cooling*, just some intake-air dehumidification in the summer.] That's where the nonlinearity comes from, so viewing long-term averages over an entire season's worth of temperature swings is really necessary because my effective "delta" is NOT represented solely by HDDs. Still, be it 160 or 190 or whatever, it's still a fraction of the losses in a typical code-built house which are up around 600 to a thousand btu/h/F or more. Further years' observations will tell more. As this little part is being written four winters after the renovation, my assertion that I'd still be collecting data on the improvements for years afterward was completely true. Maybe not taken religiously night to night going forward, but certainly season to season with periodic baseline sanity-checks to make sure there aren't any compromises in the thermal envelope's integrity. |