Flashing Error?
The window shown on the front cover of the June issue is flashed wrong. Is there any reason?
Linda Stephens
Stephens Construction
Bloomington, Ind.
Thanks for the question; others may have the same impression. We believe the window is installed correctly but that you may be mistaking the siding J-channel installed around it for the nailing fins. The vent on the lower left has the same J-channel. - The Editors
SIPs for Tight Houses
I'm writing about the story "Insulating With Exterior Spray Foam" (5/11). While I am grateful that there are builders willing to put their time and money on the line trying new techniques, this one leaves me a bit baffled. SIPs, which I use, go up faster and seal just as well; if you're concerned about thermal bridging, you can add a layer of foam to the outside, taped and strapped for the siding. The floor joists are hung on the inside of the walls so the rim joist is eliminated. If I use common trusses, I usually spray 1 to 2 inches of foam on top of the ceiling drywall, sealing any penetrations and boxing in fixtures where needed, then blow in at least 24 inches of cellulose. These techniques allow me to build well-insulated structures that consistently test at less than .5 ACH at 50 pascals.
Chris Norman
Boreal Craft
Grand Marais, Minn.
Don't Glue Sheathing in Seismic Zones
A letter in the June 2011 issue ("Gluing Sheathing Improves Air Sealing") suggests attaching wall sheathing with adhesive. This could be a code violation in earthquake country. The "Special Design Provisions for Wind and Seismic" (SDPWS) governs wood-framed construction; SDPWS Section 4.3.6.3.1 states that "adhesive attachment of shear wall sheathing shall not be used alone, or in combination with mechanical fasteners." An exception to this provision allows using adhesives in Seismic Design Categories A, B, and C, but only with a severe penalty (the entire structural system must be designed to withstand about four times the earthquake force required for shear panels attached with nails alone). Almost all construction in California falls into Seismic Design Categories D, E, or F, so using adhesive on shear panels here is completely out of the question.
Attaching shear panels with adhesive creates a stiffer wall; stiff structural systems "attract" more earthquake loads than flexible systems. Adhesive attachment robs a shear wall of its ductility, which is beneficial in absorbing earthquake energy. This increases the chance of sudden, "brittle" structural failures, which are the most devastating in earthquakes.
Thor Matteson, S.E.
Berkeley, Calif.
Phone Smarts
As a 64-year-old baby-boom geezer, I had my doubts about my new smartphone until a recent experience saved me some serious money. I have a 10-year-old Galaxy 2000 8-inch belt sander that I use in my wood-flooring business; with its 7 1/2-horse 220-volt motor, that machine is a bear. It was running poorly on a job recently and needed expert maintenance - it sounded like bearings or the start/run capacitor. The problem was that there wasn't an authorized dealer within 130 miles of Atlanta; I was looking at a day of downtime just to get it to a shop in a city a few hours away. So I called the manufacturer in Toronto and tried troubleshooting with a technician there. He immediately asked if I had an iPhone, then asked me to shoot a short video and text it to him so he could analyze what he saw and heard. It turns out the idler arm was stuck and the fan belt had stretched. He explained to me how to free up the idler arm, and a short time later I had replaced the belt and was back to work. The several-hundred-dollar repair and full day of downtime I was anticipating was resolved in minutes for the cost of a fan belt I already had in my shop! I'm not ready to do Twitter yet, but I'll be looking for more ways for my smartphone to help out an old dumbass.
Michael Purser
The Rosebud Co.
Atlanta
