The real purpose of duct tape

I took a break from the project for a couple of weeks surrounding the July 4 holiday, but the midsummer heat provided me fresh incentive to get to the next inspection – then close up the ceiling so that we can use our attic fan and air conditioning.

To that end, I finished all the rough wiring over the weekend and installed the HVAC duct for the new room.

A long, silvery 6" flexible air duct, which consists of a circular inner duct made of a mylar-type material supported by coiled spring wire.  The inner duct is wrapped with fiberglass insulation and outer foil. I stretched the duct out on the floor and assembled as much of it as possible prior to pulling it into the attic, which is hot, dirty, cramped, and full of fiberglass insulation – just miserable to work in. (I had to buy 25 feet of duct in a box, but only used 12 feet.  If anybody wants the other 13 feet, let me know!)

For the air conditioning/heating outlet, I cut this 6" x 10" opening through the bedroom ceiling. (Below: The metal box will sit atop the ceiling opening.)

Using screws and duct tape, I attached one sheet-metal elbow to the rectangular box to help shape a gentle bend in the duct. (A tight bend or crimp might impede air flow.)  Then I attached the inner tube to the metal using duct tape, and secured the outer insulation with tape and large cable-tie straps.

Rather than drag the duct through the attic opening down the hallway, I pushed it up through this ceiling hole above the new closet, which is almost directly below the attic furnace.

In addition to pulling the duct through this opening, I also pushed my tools through this hatch, avoiding the struggle of carrying them the length of the attic while crab-walking on the joists. And although I couldn't easily crawl upward through this opening, I could jump down through it – much easier than crab-walking back to the traditional attic hatch.  Especially when you have to go up and down about 15 times, which is what it took me to complete this HVAC installation.  Every time I came down through this opening – hot, dirty, miserable, and swearing – Anne would hear the commotion and ask me if all was okay.   And, occasionally she would offer me a cup of tea.

This is the air outlet, now installed atop the ceiling drywall. (It is the unit I that I assembled on the floor, shown in the first few photos of this post.) I used construction adhesive to glue it to the top of the drywall and then put these temporary screws through the ceiling to pull it tight against the drywall.  Once the room is finished and painted, I will attach the air-register grille.

The new, foil air duct inside the attic. After I attached the outlet-box to the ceiling hole, I packed fiberglass insulation around it.

This is the furnace plenum chamber, a huge metal box that collects all the hot/cold air coming out of the unit and distributes it via flexible ducts. Rather than disturbing any of the existing ducts, which are 20 years old and somewhat brittle, I decided to cut a hole through this metal wall and install a new opening.  I started by drawing a 6" circle (above).

I cut the hole using a jig saw with metal-cutting blade. First, I drilled a 1/4" hole so that I could push the jig saw blade through, then I cut the circle. I had to poke my arm through this hole and vacuum up all the metal "sawdust" lest it blow through the house next time I turn the AC on.

This is the duct connection to the plenum chamber. It has metal tabs that bend outward to hold it in place from the inside.  For a tighter seal, I also used sheet metal screws around the flange.

Next, I attached an elbow to help avoid any radical turns in the duct that could impede air flow.

Finally, I attached the new duct (right), and re-wrapped the plenum chamber with fiberglass insulation.


Below: Final pre-inspection work

The large, gray circuit breaker at the bottom of the panel is an "arc fault circuit interrupter," the latest innovation in home-fire prevention required by the national electrical code. It takes a double-slot on the panel.  To install this, I turned off all power, removed the panel-facing, and fished a No. 12 romex cable down though the wall from inside the garage. The photos below show that cable, which provides power to the new Tea Room.

The yellow cable to the right carries power from the AFCI breaker up to a new outlet in the office, then back down through the white cable to the Tea Room.

The yellow cable is routed through the garage "chase" and down to the electrical panel. I managed to do all of this without disturbing the Dallas Cowboys pennant on the wall.

Office junction:  The upper box is the terminus for CAT-5 and CAT-6 ethernet cables. The lower box serves 4 functions:  (1) brings power along the new AFCI circuit from the main panel; (2) sends that power onward to the Tea Room; (3) provides a new office outlet for my computer equipment; (4) sends the power to a new office outlet for ironing (below).

This new outlet is for ironing and vacuum-cleaning.  I have politely requested that there be no ironing board placed in the posh new Tea Room.  The compromise was to install a more-convenient outlet in the office for the iron.

Stucco mesh:  I intend to finish nailing up this netting by Friday, then request my second building inspection on Monday. The reinforcing mesh is attached with special "furring" nails that push the wire slightly away from the wall so that the stucco will flow behind it and totally encase it.