Episode 008 1995 - 96 Season

| House Wrap | Fiberglass Wall Insulation | Sun Tunnel Skylights | Accessorizing (design) | Building with Bricks | Conventional Loans | |

To order a Video Tape, call 1-800-TO-BUILD and ask for Episode #008.


Fiberglass Wall Insulation

Michael Holigan: Now that we've put the wind breaker on the outside of the house it's time to come inside and add the insulation. We've got an insulation specialist with us, we've got Craig Smith with Williams Insulation, good to have you here Craig.

Craig Smith: Thank you, Michael. It's a pleasure to be here.

M.H.: Hey, tell us about wall insulation here. Now, before we even get started though, I need to know about R-Values. We're going to start throwing out numbers and R-Values, and everyone always asks "What is an R-Value?".

C.S.: R-Values are just a real simple measure of a materials effectiveness to resist the flow of heat and cold through it. Everything has an R-Value. This 2x6 wall stud here has an R-Value, the exterior sheathing has an R-Value, and the insulation has an R-Value.

M.H.: Okay, do they want a high R-Value or do they want a low R-Value?

C.S.: The higher the R-Value, the better the insulated value, the better resistance to the heat and flow of cold. For instance, an R-11 bat would be about half as efficient as an R-22 bat.

M.H.: We want it as thick as possible then, the highest "R" number possible, because that means the lowest utility bills?

C.S.: That's correct.

M.H.: Well let's start right here. What bat have we got in this 2x6 wall?

C.S.: You're presently using an unfaced R-19 bat, okay, which is the highest R-Value that you can put into a 2x6 cavity, strictly speaking about the wool insulation.

M.H.: Why can't we put more insulation on top of that, an R-30 bat?

C.S.: The insulation, if it's compacted, if it's pressed down, let's say, for instance, that we tried to put this R-19 bat into a 2x4 cavity.

M.H.: Ah-huh.

C.S.: What we would have to do is compress the bat, and what we don't want to do is compress the bat because, this bat gets it's R-Value both from the material that's in that 6 inches, and from the air pockets that are created by the material. If we were to compress it, what we would be doing is losing those air pockets, and therefore we would be losing some of the R-Value.

M.H.: Okay.

C.S.: I really can't tell you what that R-Value would be, if we compressed it down to 4 inches, but it would be something less than an R-19.

M.H.: So you definitely want a thick wall cavity so you can get as much insulation as possible, so, the 2x4, what are you limited to?

C.S.: R-13.

M.H.: Okay, and the 2x6 that we have here? You can go all the way to an R-19?

C.S.: Exactly.

M.H.: Is the price very different for the insulation itself?

C.S.: Let's say a standard 2,000 square foot house, you're talking about $150 difference in an exterior wall of R-13 versus an exterior wall of R-19.

M.H.: You can pay for that in the first year, can't you?

C.S.: You sure can, yeah.

M.H.: How about around the wires. I see a lot of builders, when they're bringing the insulation down, and they have a wire that's halfway through the stud, they just compress the insulation around it, and it's not on this side. What happens there?

C.S.: Well you'll notice that our insulators, what they did here was to actually split the bat lengthwise, putting half the bat on one side of the wire and half the bat on the other side of the wire. What that does is give you that, that absolute 6 inch depth right here that's necessary for the insulation to perform the way it should. If we were just to shove that bat behind the wire, what we would do is create a compressed area along the line of the wire, which would be something less than an R-19.

M.H.: So we might have had a cold area along the wall right there in the winter or a hot area during the summer?

C.S.: Exactly.

M.H.: And Craig, I guess there's going to be one other difference with the thicker insulation, and that's sound.

C.S.: Right. The thicker the insulation on the exterior wall, the better it impedes the sound flow through it, so, if you have 2x6 walls, you put 6 inches full of insulation in here, it's going to make a quieter home.

M.H.: All right. Craig, appreciate the help. See you in a couple of weeks. We'll go upstairs and insulate the attic.

C.S.: Thank you Michael.

Episode 008 1995 - 96 Season

| House Wrap | Fiberglass Wall Insulation | Sun Tunnel Skylights | Accessorizing (design) | Building with Bricks | Conventional Loans | |

To order a Video Tape, call 1-800-TO-BUILD and ask for Episode #008.