Ah, Go Insulate Yourself!

5 Dec

After a long on-line debate today about insulation, I want you to think about these facts…

About fiberglass insulation:

People tell me that they can’t afford to pay for closed-cell SPF foam insulation. They say that they can do the same thing by simply  using fiberglass.

I regularly apply SPF to provide at LEAST an r19 on the exterior walls of a container. That’s about a depth of 2.75 inches of foam. SPF will get you an r7 per inch. So, in less than three inches, we get our r19 all day long.

It doesn’t “settle”.

It doesn’t decay or degrade over time.

It doesn’t absorb water and turn into useless mush.

Shoot it on and forget about it… forever.

But the naysayers frame out the inside of their containers using 2×6 construction (to create really “deep” cavities) and then they stuff that nasty pink stuff into it.

What have they accomplished, besides taking up valuable square footage INSIDE?

Not much.

Did you know that;

r19 fiberglass batts for 2×6 walls, manufactured by Owens Corning require a 6 and 1/4 inch space to install it correctly.

Um… How wide is a 2×6? It’s certainly NOT 6″. Not hardly. Last time I checked, a 2″x6″ board measured 1-1/2″ x 5-1/2″.  So, you’re gonna come up short. Now how much space did you need again?

Don’t trust me. Here’s the spec’s:

Wood Measurements (dimensions);


Fiberglass Batt install requirements for r19 batts;


So, you’ll just stuff it into that cavity between the studs anyway, right? Don’t worry… it will compress. 😉

You’ll actually end up with r17-r18 (maybe!). Industry experts will tell you it’s actually more like r15-16. And that’s IF the run has no openings like doors or windows, and you’ve been careful to prevent thermal bridging.

(But how many people actually DO that? Hmmm? Few.)

The typical wall, built in this fashion yields about an r14-15, tops… IF you are lucky.

That means it’s going to cost you more energy to keep that room stable. And energy doesn’t grow on trees… Unless you’re stuffing it into a wood stove. 😉

Keep reading…

r19 insulation almost NEVER creates a r19 wall. Not by a large margin.

Why? Because it’s very seldom installed CORRECTLY.

Thermal bridging of studs, doublers, fire blocks, sills, and headers bleeds r-value away like an open wound. And the presence of windows, plumbing, wiring, etc. all contribute to diminishing that desired result even further.

However, if you shoot SPF on the OUTSIDE of your Containers… 😉

I’m just saying… 🙂

Photo credit to: Owens Corning