Coordination Between Subs Would Be Nice

As a deck waterproofing contractor and consultant, I often see problem decks that have French doors leading out to them (see “Focus on French Doors,” 8/09). Most of the time the customer’s complaint involves a leak at the door, which usually gets blamed on the deck contractor. We often find that a sheet-metal door pan wasn’t installed — or if it was, that the door installer damaged the pan’s integrity by crushing its back lip or penetrating it with screws without caulking the penetrations. Sometimes the pan flashing is improperly placed over the building paper — as in the example shown here — rather than the other way around.

Regardless of whose fault this is, the various trades involved need to communicate more so that they work in sequence to ensure a leak-free installation. Pans and any flashings for the deck go in first, then the door can be installed.

Bill Leys

Arroyo Grande, Calif.

Barrier-Free Showers vs. Code

Regarding “Building Zero-Step Entries” (9/09): Be forewarned, the Uniform Plumbing Code requires a 2-inch minimum drop between top of finished threshold and top of drain.

I’ve built a number of showers similar to the author’s, and the inspectors allowed them as long as I had 2 inches of standing water for the rough inspection. But this year, an inspector for the city of Oakland brought up the code and refused to sign it off (there was about an inch drop in the finished shower, similar to the one shown in the article). All my entreaties to her and her supervisor about my disabled client went nowhere. We had to either tear it out and rebuild it to code or add another unsightly waterproof threshold on top of the one already built.

Jonathan Dougall

Oakland, Calif

Overbuilt

Wow, talk about overreacting! Going from an inadequate 35-cent hanger to a hard-to-install $38 HWU hanger with 10 times the required capacity is completely inappropriate in most such situations (“Hanging Loads From Beams,” Letters, 8/09). A Simpson HU216 should have plenty of strength, is simple to install from the bottom, and would cost a fraction.

Ralph Hueston Kratz, S.E.

Richmond, Calif.

Don’t Ventilate Crawlspace With Moist Outside Air

Regarding the crawlspace ventilator (Products, 8/09): First, remember that relative humidity (RH) is the measure of the percentage of water vapor in the air. The higher the temperature, the higher the possible relative humidity.

Here’s an example of why forced crawlspace or basement ventilation is a bad idea: If you have 80°F outside air with 75 percent RH and you force that under a house where the temperature is 15 to 20°F lower, the water vapor that can no longer remain in the air as it cools down will condense on available surfaces. I’ve been under houses that have forced ventilation and observed water dripping off plumbing pipes, hvac ducts, and even wooden floor joists. I have seen similar houses without forced-air ventilators but with open vents and a vapor barrier on the ground where the crawlspace is dry.

Although it’s a relatively new method, I also like the idea of sealing the crawlspace or basement and using the house’s hvac to keep the space tempered and dry. This of course does require carefully sealing all sources of water vapor.

Scott Speer

Murrells Inlet, S.C.

Code Article Misses The Boat

I was disappointed with the article “Energy Code Update” (In the News, 8/09). The author did not demonstrate much knowledge about the 2006 IECC and therefore missed the boat on highlighting the important changes in the 2009 edition. Most of the items mentioned by the author that give the IECC “flexibility” have been part of the IECC since the 2006 edition, if not before. In fact, the 2009 IECC is considerably less flexible than the 2006 edition.

For example, the article states that “an exception has been added for cathedral ceilings that allows reduced insulation in cases where roof framing will not accommodate the full R-value.” This 500-square-foot ceiling R-value exception was present in the 2006 IECC (402.2.2). The only thing that is new is the addition of “or 20 percent of the total insulated ceiling area, whichever is less.” This restriction of 20 percent of ceiling area makes this section of the IECC less flexible — not more, as implied by the article. In addition, a ceiling R-value reduction when using raised heel trusses was also present in the 2006 IECC (402.2.1), so it is not new to the 2009 IECC.

The author states, “The code now allows you to trade ceiling R-value off against wall R-value.” This is in reference to the total UA method, which, as anyone who has complied with the IECC using REScheck over the last decade knows, was also in the 2006 IECC (402.1.4) and previous code editions. In addition, this method is not limited to tradeoffs between ceiling and wall R-values, but also includes floors, windows, doors, skylights, slabs, and basement and crawlspace walls.

One item in the article is just plain wrong. The first sentence in the section on foundation insulation states, “The 2009 code adds a requirement for slab edge insulation in Zone 4 … just an R-5 (an inch of rigid foam).” First, slab edge insulation was a requirement for Zone 4 in the 2006 IECC (Table 402.1.1). Second, the required R-value is R-10 (2 inches of rigid foam) in both the 2006 and 2009 IECC editions. There were in fact no changes to slab insulation requirements in any climate zone between the 2006 and 2009 IECC.

I also take issue with the author’s depiction of the 13 plus 5 wall insulation configuration as a “loophole” that “on paper … would only be R-18.” R-13 cavity insulation plus R-5 foam sheathing will likely perform as well as if not better than R-20 cavity insulation due to the reduction of heat loss through the framing members. Saying that R-13 cavity insulation plus R-5 foam sheathing is equivalent to R-18 is highly misleading.

Mike Turns

Pennsylvania Housing Research Center

Sealing the Drip Edge

I noticed in the article “Reroofing With Asphalt Shingles” (7/09) that the author put the drip edge on top of the underlayment. In southwest Florida, where I work, that would never pass inspection; you’d have to add at least a 2-inch-wide band of flashing cement to seal the drip edge to the underlayment.

Kyle Lantz

Southwest Creations

Fort Meyers, Fla.

Correction

In “Another Look at Vinyl Siding” (9/09), IQm trim was incorrectly associated with The Foundry. In fact, it is made by Mid-America (888/289-1169, iqmtrimboards.com).