Twenty-five years old. At that age — despite my cocksure certainty about, well, most every subject that came up — it began to dawn on me that I probably didn't know nearly as much as I thought. Never so dumb as when we knew it all, a carpenter friend is fond of saying.

Fortunately, at JLC we don't have to know it all, as anyone who reads the monthly clarifications and corrections in our Letters column recognizes. From its beginnings as New England Builder, JLC has depended on the experience of its readers — builders, remodelers, and subcontractors of all stripes, making a living in one of the toughest but ultimately most satisfying professions anywhere — to keep the discussion on track. Without your continued support and participation over the years, there would be no JLC.

To mark the anniversary, we've varied our typical format with a series of stories that recap some of the recurring issues we've covered in the last quarter century. In "Energy & Moisture Matters," Joe Lstiburek, Terry Brennan, Paul Fisette, Martin Holladay, and Paul Eldrenkamp take turns answering questions about air infiltration, moisture movement, and energy loss. What emerges is a consensus about some of the central lessons of the last couple of decades: R-value without air sealing is worthless; air sealing without ventilation can be deadly; better to build so that things stay dry, but when things do get wet — as they will — better have a way to let them dry.

In "Roof Ventilation Update," researcher Bill Rose rolls up more than 20 years' scientific observation of attic performance. Anyone who's followed the decades-long debate around roof venting will appreciate how he navigates the seemingly infinite number of variables and points to designs that work.

We asked technology expert Joe Stoddard to cast an eye not only backward but forward, into the future — the technology future, which seems to arrive anew every day, fast and furious and ever-changing. If you want to know which technology tools are essential to your business survival, read his story, "Connecting All Contractors."

We also invited longtime design columnist Gordon Tully to join the party. In an era when 10,000-square-foot single-family mansions are hyped as "green" just because they have a few advanced energy features, Tully shares tips on the greenest idea of all: small houses.

No birthday celebration is complete without a party favor, so for fun we turned illustrator Tim Healey loose for a few pages, to see what might evolve. Oh, and don't forget to read Backfill: It's 100 percent recycled content — an article written for New England Builder in 1983 by a little-known freelance writer who soon after landed a job with the Miami Herald and had to give up his gig with us. Check it out.

Enjoy the issue, and keep those letters coming.

Don Jackson

JLC Editor

Permeance of Foam In Unvented Attics

The letter "Open-Cell Foams Can Work in Unvented Attics" (8/07) states that Demilec, USA, voices no concern about installing open-cell foam in an unvented attic assembly.

I'm afraid we here in Massachusetts have to adhere to a higher authority: The recently adopted Massachusetts Building Code, Section 5806.1.1, states that foam may be used in unvented attics without a vapor barrier if the permeability of the foam is less than 2 perm-inches. No open-cell foam has a permeability that low, though closed-cell foams generally do.

Robert Jordan

Upton, Mass.

Electrical Red Flag

The wiring diagram for a three-way switch (Q&A, 7/07) contains a common code violation. Section 200.7(C)(2) of the 2005 National Electric Code requires that the ungrounded white conductor in this example be used only to supply power to the switches and not as a return conductor from the switches to the lights. This means that the white wire connected to the light fixture will always be a neutral, and the hot return from the switch to the light fixture will always be the factory-colored black or red. This should prevent anyone working at the light from confusing the reidentified white conductor with the white neutral at the fixture.

Lee Edelberg, Electrician

Leverett, Mass.

Short-Sighted?

Hispanic immigrants are "crucial to [our] industry" (In the News, 8/07) in the same way that cheap Chinese imports are "crucial" to our economy. Both displace and bankrupt millions of American workers and erode the same middle class that currently makes up our largest consumer group. Both represent a serious threat to the stability of our society, our jobs, and our economy.

Neither can exist, however, without our greedy, exploitative, self-serving willingness to disregard common sense and responsibility in order to earn short-term profits at the expense of our fragile, floundering, yet precious lifestyle.

The consequences are real, and imminent.

Robert Beauchamp, General Residential Contractor

Eugene, Ore.

No Sympathy

I couldn't care less how important the Pew Hispanic Center thinks these "recently arrived" Hispanic workers are to the American economy. The fact is they are here illegally and are therefore breaking the law. My two best friends are of Mexican descent, and this subject aggravates them as much it does me. Their families immigrated legally, as it's supposed to be. Anyone who is unwilling to go through the legal process has no sympathy from me, nor do they deserve any special treatment or benefits from our society.

Marty Bolter

Bolter Construction

Groveland, Calif.