cistern

The rainwater cistern arrived today. We're using a 3,000-gallon polyethylene tank made by Norwesco, which was sourced by the company that designed and provided our rainwater filtration system, Rainwater Management Systems. The indoor components - a pump and three filters - have already been installed, and the next step is to connect the cistern to our gutters and to the filters.

The tank weighs 404 pounds empty (12 tons when full of water), so wrangling it around the side of the house took the efforts of three steel workers, two truck drivers and one surprisingly limber professor...

on staying dry

The rain has been falling fairly steadily for a few hours in Miami, which made for a good day to check the interior of tin box for leaks. So far, it looks reassuringly dry inside. In fact, there's no sign of water inside the house, which means the roof, walls, windows, doors and vents are all working as intended. The strategies we've taken to ensure weather-tightness should help us avoid the considerable costs of repairs related to leaky roofs. These include:

utilities and services

Earlier this week, our photovoltaic (solar-electric) installer connected the wires for the p/v panels through the holes we'd carefully drilled through the steel trim at the top of the upper roof. These wires will be concealed beneath, and protected by, the final piece of trim that gets installed as a cap over the top edges of the roof's standing seams. Once the cap trim is in place, the roof will be finished.

David drilling holes

David has been drilling holes at the top of the roof this weekend so that the wiring for the solar panels can be hidden under a piece of trim.

We also sprayed in more insulation in the mechanical lofts. It's our weekend to be monkeys.

flashing

Like any house, tin box has a number of holes in the roof to allow plumbing and mechanical vents to draw noxious, humid or lint-filled air out of the building. Each of these penetrations provides an opportunity for rainwater and critters to come inside, and so we need to use flashing to provide water-tight seals around the vents. All but one of the vents (the plumbing vent shown here) are protected by the overhang of the upper roof, which provides a comforting redundancy. The vent pipes are flashed with Dektite pipe boots, which adjust to fit a wide range of pipes, and which have a flexible base to accommodate different roof types. The pipe boots are held in place by mechanical fasteners and made watertight with a bead of sealant.

trim

Our steel erectors, Mike and John, have finished installing most of the steel trim on the outside of the house. The trim provides a clean finish at places where the building materials have been cut roughly and where we've used expanding foam insulation to fill the gaps between the walls and roof. Trim is generally a decorative element, whereas flashing is used to keep water from infiltrating the house. At tin box, both the trim and the flashing are made from sheet metal which has been finished in the same Kynar coating as the wall panels.

solar power

Just when we thought we'd spend the next few days writing about the fantastic door and window installation at tin box, the crew from Electron Solar Energy arrived to install the flexible Uni-solar photovoltaic electrical panels we purchased from the Energy Store. Here's a photo of the first panel going up this morning.

roof panels complete

Late this afternoon, the steel erector installed the last of the insulated roof panels. There's still a lot of work to do on the roofs, including trim, gutters and photovoltaic panels, but it's really nice to see all the panels in place.

roof, again

An addendum to our earlier post about the upper roof. The first photo shows the upper roof with its b-deck sheathing, while the lower image shows the insulated roof panels installed. One difference is reflectivity; the galvanized b-deck is almost mirror-like, and reflects light much more brilliantly. In fact, it casts the kind of harsh glare that caused the Miami Marlins to revise the finish on their new stadium in Little Havana (see below). The duller finish of the galvalume paint on the roof panels, however, moderates the amount of sunlight reflected into our neighbors' houses, which is a good thing.

The other difference has to do with grain and pattern. The wider spacing of the standing seams in the roof panels makes the roof - and the house as a whole - seem less broad than it did when the roof was covered with just b-decking.

We're curious to see how the roof changes when we install the photovoltaic panels. In the meantime, bonus photos of Miami's biggest tin box, the new Marlins stadium:

roof

Our steel erector set the insulated panels in place on the upper roof yesterday. These panels, each 42" wide, run the full 18' length of the roof slope in order to eliminate the kinds of lap joints that might leak. The standing seam joints between the panels also eliminate leaks (by raising the seam well above the roof surface) and hold the panels in place by crimping around the stainless steel clips that are screwed through the corrugated b-deck and into the z-purlins.

The installation process includes two kinds of sealants to complete the moisture and thermal barrier:

roof panels

Our steel erector began putting the insulated roof panels up this week. Together with the insulated wall panels and the metal trim, this comprises the final layer in the prefabricated shell of the house. The panels themselves are pretty impressive:

roof decking complete

The erectors completed the roof decking this morning. We're now ready for the insulated roof panels to go up (then wall panels, then windows and doors). The house is looking pretty cool.

the week ahead

Looking forward at the week ahead, we're anticipating a lot of work at tin box. Our erector should be able to finish installing the roof decking this week (we're still waiting on two pieces of steel that weren't shipped with the z-purlins). The exterior roof panels arrive Tuesday, and should start going up right away. Our panel manufacturer plans to begin fabricating the exterior wall panels Monday and deliver them to the site Friday.

Meanwhile, the neighbors clearly approve of the project...

decking

Our erector started installing the roof decking yesterday. These gorgeous corrugated sheets are High Shear B Deck (HSB-36), a structural roof decking that comes in 36" wide and 1.5" deep sheets. The decking is fastened to the z-purlins with TEK screws (which don't need a pre-drilled hole), and will act as a structural diaphragm under the insulated roof panels, which are also structural. Together, the decking and roof panels will deal with the combination of tensile, compressive and shear forces generated by hurricane force winds. They will also support the weight of the vegetated roof that we plan to add someday.

The B Deck will also make for a great ceiling, in combination with the z-purlins...

roof

From the Kingspan factory in Deland, FL, comes this progress photo of our roof panels. Our roof uses KingZip insulated metal panels with a standing-seam joint. We chose 4" thick panels, which will give us an insulating value of R-32 (exceptional by Florida standards). We could have gone up to 6" thick, which yields R-48, but this would be a bit excessive in South Florida.

Each 42" wide panel will hold two solar panels, which adhere directly to the steel surface of the roof panels. The panels have a galvalume finish whose high albedo value (a measure of reflectivity) means they will reflect most of the sunlight that hits them, minimizing the direct heat gain.

The roof panels are cut to length in the factory, which helps eliminate on-site waste and reduce energy wasted in transit (one benefit to prefabrication). The pieces can come in lengths up to 52', the length of a flatbed truck. Our longest pieces are about 32'. We'll write more about the roof when it starts arriving, early next week.