Thursday, December 21, 2006

Dry wall really makes the timbers pop!

With the weather outside turning nasty, and the roof almost finished, we've turned out attention to hanging the drywall on the inside of the house. Like everything else, this is turning out to be a bigger job than I had imagined. The biggest time sink is cleaning (with bleach and/or sand paper) all of the weathered timbers inside the house. I'm not bothering to oil or finish the timbers at this point, because the mud-tape-sanding of the drywall is going to generate a lot of dust that could stick to the linseed oil. When we're completely done with the drywall, we'll go back and oil the timbers (hopefully one last time!).

The timberframe has never looked as good as the day it was standing naked against the blue sky. In fact, it kind of disappeared in the details of the rest of the house. But with each sheet of drywall that we hang, the timbers "re-emerge" more and more from the background of SIPs and studs. So with the exception of the laborious sanding, this is a very exciting (if not slow) stage of the project.

There is a fairly standard trick to hanging drywall in a timber frame house: When you install the SIPs, you hold them away from the timbers using 5/8" strips of wood or plywood. This gives you ample room later to slide a piece of 1/2" dry wall behind the timbers and knee braces. As the timbers and braces shrink, they simply expose more of the drywall. The alternative would be to fasten the SIPs directly against the timbers, but then you would have to butt your drywall up to the timbers and cut drywall to fit around the braces - not desirable, especially since these timbers are still shrinking! Here's a picture that illustrates the intentional gap we left between the SIPs and timbers.

Lighting a timberframe with fluorescent....

Now that we've got some electricity in the house, I've been thinking about and experimenting with lighting. Being that we're running on solar electricity, we've pretty much ruled out the beautiful, but inefficient, halogen track lighting that you see in the glossy timberframe magazines. With "Lowe" expectations, I went to Lowes looking for a suitable fluorescent substitute for incandescent track lighting. Much to my surprise, there have been several innovations in fluorescent lighting in the past two years. 20 years ago, all you could buy were the "long tubes," used in schools and workshops. Then came the "twisty" shaped bulbs that are a drop in substitute for regular light bulbs (these are wonderful). Now you can buy fluorescent lighting in really tiny, self contained form factors.

The small packages include the bulbs, switch, ballast, and starter... and you can even string them together in long chains. Based on the packaging, I'd say the initial target market for these new form factors is "under kitchen cabinet lighting." But I've found you can do some neat things with these little packages. For instance, I hid 8 of them above the top plates in my "tower room" and the light just seems to come from no where and illuminate the entire roof structure. What's more, because the light bounces off of the tongue and groove ceilings before illuminating the room, the inherently "cold" nature of the fluorescents lights is tempered to a "warmer" glow. Very neat, more examples to come! (There's a lot more glare in this picture than in real life - I had to take the photo without the flash on.)

Stealth Airplane or Cricket?

A "cricket" is the word used to describe a roofing feature whose purpose is to divert water where two roofing planes intersect. I needed a cricket where the tower roof intersects the main roof. Technically, the cricket was already built of lumber and covered with felt paper. What I needed to build now was the flashing for the cricket. I chose stainless steel flashing, because this would be one of the most difficult areas to "reflash," should the flashing ever wear out. Copper flashing would have been easier to fabricate, but could have worn out in 50 to 75 years. I'm hoping the stainless will last much longer. Yeah, yeah, I know I'll be dead by then, but I wouldn't want to burden the next owner with this onerous task (one of my kids?).

I cut the pattern from a sheet of 18 gauge stainless steel (anything thinner is almost impossible to MIG weld with my Lincoln) using a Stihl chop saw with an abrasive cutting disk. My bro-in-law helped me brake (sheetmetal term for "bend" or "crease") the angles using a bulldozer blade to clamp the stainless between two straight pieces of wood. I shoved on the steel, and he convinced it to fold using a hammer. Much to our surprise, the whole shebang started looking like an F-117 very quickly! I went over one of my welds with solder to make sure any pinholes would be sealed, but this was a real pain in the butt, because the weld spatter and gas had really contaminated the stainless. After that little detour, I decided to just go over all of my welds a second time with the MIG and call it "good."

It took two days for me to fabricate this thing (which included wrestling this monster on and off the roof for test fitting a few times). Like I said, copper would have been easier. The bottom right picture in the photo-collage shows the final piece in place on the roof. Helicopter passengers notwithstanding, no one will really ever see this detail on my house. I've also got to think... perhaps someone who does this for a living is going to read this and laugh his butt off when he sees how I made my cricket. As long as it works... forever... I don't care. :)

Saturday, December 09, 2006

The day we turned the generator off...

Wednesday, with 3 solar panels mounted to the roof, most of the circuits pulled into the main breaker box, and the inverter station wired to the breaker box, I realized that we could test out the entire power center for the house, if only I had the batteries on site and wired. I drove the backhoe to my workshop where the batteries were stored and brought them up to the house site. We wired them in a temporary location in the basement and ran the heavy 0000 ("four ot") gauge cables to the inverter panel. We had been backfeeding the breaker box with a honda generator, so we were careful to disconnect the generator from the "mains." Of course, our flourescent lighting went out as soon as we took the generator down. But then I threw the DC switch that connects the batteries to the "Master" inverter. LEDs flickered, Red, yellow, green, two greens, go! The inverter's cooling fan came on momentarily and then spun back down and everything seemed happy, so I threw the switch to the second "Slave" inverter. It performed exactly the same dance of lights and fan noises but settled into a blinking green LED state, because it was waiting in standby-mode for the power consuumption to warrant its active participation. Satisfied that everything was happy and dying of anticipation (sorry, I should clarify... the inverters were happy, and I was dying), I threw the switch that connects the inverters to the house's breaker box. The lights came back on! We were running on battery power! Not exactly solar power, but an important first step.

Quickly I ran outside and warmed up the crane. I thought I could temporarily wire the solar panels before it got dark... it wouldn't look pretty but it should work for testing purposes. My bro-in-law flew me up to the roof on the end of the crane and I wired 3 panels in series, made a make-shift strain-relief, and dropped the two leads back to the ground. When I got back to the ground, I shut the system back off and wired the solar leads to the MX-60 MPPT. (yes I know, there are supposed to be DC circuit breakers, lightning arrestors, conduit, and a chassis ground in this part of the story, but those will come soon, I promise) Satisfied that I had the polarity correct, I powered the inverters back up, and then turned on the MPPT. It woke up with a fancy display on its lcd screen, but then pronounced it was "snoozing". Snoozing?!?! At a time like this, how could it just sit there and snooze?! I looked outside and saw that the sun had set behind the hills... but surely there was enough light left to keep this thing from snoozing?! I started jumping through the menus on the MX60's display - aha there it was... a way to lower the current threshold so my MX60 wouldn't snooze in low light levels. But the system asked for my password and, defeated but not broken, I decided it was time to RTFM. There it was, on page B.26 the factory default password! By the time I got the password in the system and lower the cut-in threshold, the MX60 declared that it was now "Sleeping!" It was now dark outside... my window of opportunity had passed and I would have to wait one more day to "Go Solar."

Thursday started out cloudy, and then turned to snowy. With snow accumulating on the panels, it seemed like there was no hope of "going solar." Much to my surprise, the MX60 decided to wake up and started serving 5.... 10.... 15 watts of power to the batteries. Soon, it was reading 200 watts, even with snow on the panels. That did it, I pulled all of the generator wiring from the breaker box and decided that we were now "Solar!" Of course, I got little done that day - I couldn't take my eyes off of the status display on the MX 60. Every 5 minutes, I would run down to the basement and see how many watts we were producing and check our battery voltage. Before the end of the day, we registered a high of 400 watts from the 624 rated-watt panels. In fact, due to meager use of power tools and flourescent lighting, we finished the day with almost as much energy in our batteries as when we started!

Friday, the sky was clear for much of the day and we produced a whopping 1.7 Kwhrs by 2:00 pm - which was again enough to meet our power needs without ever turning on the generator. Bouyed by the success, and addicted to solar power, I decided to connect 3 more panels for a total of 6. (when in fact, what I really should be doing is working on the permanent installation of all of the panels, or the flashing for that slate roof.) We brought the second set of panels on-line at about 3:45pm - just in time to see 300+ watts from each set of 3 panels.

We didn't work today (Saturday), but I had to visit the house site and see how the panels were performing. Each set of panels was producing approximately 540 watts of power - almost 90% of their best case rating and the 48 volt batteries were at 54 volts! So, even though they're not permanently wired, these panels are permanently mounted. Eventually, I will cover the entire south roof with 48 solar panels, for a total electricity generating capacity of 10,000 watts in the noon sun. But for now I think we have enough electricity to run all of our tools.

Quick roof update

We've finished the slate on the hip roof section of the house and the last dormer. I broke down and put felt paper on the rest of the roof, so that we have _some_ form of roof (80% permanent, 20% temporary) on all of the house at this point. Every window is installed (even the basement windows!), and we've tarped all of the door openings, so that we can actually try to heat the inside of the house. Until I can decide on which brand of outside wood furnace to buy, we're using a barrel stove (inside the house) that I bought at a scrap yard for salvage metal prices.

When we get a spell of good weather, I'll climb back out on the roof (through the upper left most tower window in this picture) and start fabricating the flashing that forms the cricket and valleys where the tower roof intersects the main roof. Not a job I look forward to, but it must be done. Although I don't think it looks as nice, I plan to make this valley an "open valley" as opposed to a "closed valley." This will allow us to walk on the valley without breaking slates, and more importantly, it will allow us to slate the main roof and the tower roof independently of each other.

For two years, my wife has kept a signed contract on the fridge in which I pledged that "Thanksgiving 2006 will be in our new house." Well, Thanksgiving morning came, and I wasn't even close to fulfilling the contract so I gave my concession speech and pleaded for an extension, duly noting that several changes and expansions of scope had crept into the work order. (we were originally going to outsource the foundation and slate roof) In all honesty, I'd say I'm about 1 year behind scedule, but it could be longer. In any case, it feels really good to not have water pouring through the structure anymore. :)