Mr. Insulation

I met with Josh Brown of Arrow Insulation. He confirmed that the city wants R-49 in the ceiling and R-21 in the walls. He looked at the 2" of balsam wool I uncovered in the dining room and said that it looked like brand name "Silva Wool," a shredded wood product of Weyerhauser in the 1940s. The good thing about the product is that it is "encapsulated" with waterproof paper, so it generally doesn't rot or grow mold. The Internet says it does not contain asbestos.

To Josh, this means we should blow in dense-packed cellulose from the inside. The procedure involves drilling a 2" diameter hole in the drywall about 4' off the floor. They push a hose up to the top of the cavity and push in the cellulose, moving down. They force it in at a higher pressure than it's natural settle pressure. When the cellulose gets to the hole, they put the hose at the bottom of the void. They have 2" diameter wood plugs with tapered sides that press into the drywall holes. They tap the plugs with a hammer until they are just below the face, ready for drywall mud and sanding.


I asked Josh about achieving R-21 when fiberglass batts give R-3.2 per inch. That's just R-11.2 in a 2x4 void. Yes, that's right, he said, but they have new magic batts that give R-15, and that's okay with the city in old 2x4 walls. The city wants 2x6 studs for insulation purposes these days, because they want that R-21. And ordinary batts in a 2x6 void are just R-17.6 (we used to say R-19). To get the R-21, you have to use the magic stuff which is more expensive. What Josh didn't say is that the city wants what it wants in an assembly, and you get to count R-0.5 for the drywall and R-0.5 for the wood siding.

For the attic, he said don't remove the old rock wool, just insulate on top of it. Take it out if there has been water damage or serious rodent infestation, but if it's just dirty, cover it up and save the money. He calls for blown cellulose in the attic, not batts. They install rulers, then blast away with a hose until it hits the right mark on the rulers. One ruler for every 300 SF of attic.

In the garage, he didn't like the batts in the roof rafters--very bad form if there was heat in the garage--mold could grow if the batts trapped moist air. I assured him there was no heat, and only some of the rafters have batts, anyway. I realized that I don't know what's in the BR3 ceiling--it's covered by plywood.

In the basement, no problem--foil-faced batts in the lower half of the 2x8 space, foil up, next to the hydronic tubing.

Arrow also handles ducting and they would be glad to install remote inline fans for the bathrooms as well as a straight-line dryer vent.

Lastly, we talked about the recessed can lights in the existing kitchen. He took out a bulb and read PR75ICX from the inside. That should mean the fixture is suitable for direct contact with insulation (IC), maximum bulb 75W. Searching the Internet, it looks like a Capri 5" IC-rated fixture. We have 6 in the kitchen and 3 more in BA1.

www.arrow-insulation.com
josh@arrow-insulation.com