Basement Insulation By and For Dummies

ceiling insulation

Every once in a while we run across freelancers who seem to have the necessary background for the content they submit to sites like the once and future eHow.com; yet their words belie their supposed expertise. We don't know whether they were padding their resumes, their content was mangled by the content editing process, or they were just incapable of putting that knowledge into words. Today's nominee is one such, a gent who claims to own a "spray foam insulation business," yet Matthew McCullough didn't do a particularly good job with the HomeSteady.com post "How to Install Basement Insulation in the Ceiling" — not good at all...

Although McCullough repeatedly suggested using (professionally-installed) spray foam insulation, he spent the majority of his post explaining how to install fiberglass batts. We were a little taken aback by his notion that,

"If the floor is concrete, then just about any type of insulation can be installed in the ceiling. If the floor is soil or soil with a poly-vapor barrier, however..."

We find it a little weird that someone who claims to have an insulation business doesn't know the difference between a basement and a crawl space, but what the hey. No, we were taken aback by some of the "facts" that Matt rattled off. Take this, for instance:

"Measure the square footage of insulation required, and multiply the result by 0.9 in order to purchase the correct amount of insulation. Multiplying by 0.9 removes the widths of joists so you don't end up with several extra bags of insulation at the end of the project."

That looks very much like Matt was conflating estimating for his business with measuring for batts. In reality, you measure the length of a run of floor joists and multiply by the number of spaces. Or how about his notion of the depth of joists:

"Use R-19 or 5-inch thick insulation for a 2-by-6-inch joist. Use high-density R-30 or 8-inch thick insulation for a 2-by-8-inch joist, R-30 or 10-inch thick insulation for a 2-by-10-inch joist and R-38 or 12-inch-thick insulation for joists larger than 10 inches."

Sorry, Matt: R-19 is 6¼" thick and R-30 is 10" – but you got R-38 right. However, you can't use 10-inch thick insulation on 2 -by-10 joists, 'cause they're only 9¼" wide. And last (but not least) Matt correctly says to install kraft-faced insulation with the paper toward the heated space, but here's how he says to install it:

"Simply push the insulation into place between the ceiling joists, and staple the paper to the underside of the subfloor with a staple gun."

Yeah: that's gonna be easy...

So we submit to you: here's a guy who claims to own a business that insulates houses and to build LEED-certified green houses. Is he competent, or is he a Dumbass of the Day? Hint: we've named him our DotD...

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DDIY - INSULATION