Need advice on Icynene, insulation and solar

[sweetczz]

I live in York PA and I'm interested in using Icynene for crawl space and attic insulation. Crawl space should be R-19 and Attic R-49 to my understanding. I hear Icynene is so good that it does not need to be R-19/R-49.

However, the Dept of energy states that a well insulated house has good Conduction, Convection and Radiation. I'm reading closed cell probably works best. I have a colonial home in York PA approximately 30 x 24. I'm willing to spend 6k to insulate - maybe more UNLESS there is better solar on the market for the same price,.

Can anyone give me advice on how to get that conduction, convection, and radiation and what type of insulation? I've had at least 6 different people come in and they all say something different. None of them talked about conduction, convection or radiation.

One contractor said that my crawlspace floor needed a barrier, seal all cracks etc, put up new R-19 insulation for $6500.00! That's not even the attic. He says just spray in the floor with cellulose to get an R-49 value and don't worry about the walls of the attic (which have improperly installed R- values mixed from R-19 to R-22, approximately $2,500).

I'm reading that the attic should have all cracks sealed but Icynene will do all this which makes it a good contender as well as being fire retardant if done properly to code.

Any suggestions on the most energy efficient way to insulate my attic and crawl space to code? Alternatively any Solar Energy I could look into? Thanks.

[Tom Raymond]

Your contractor is right about the vapor barrier in the crawl. Remove any debris, put 6 mil poly on the floor, lap seams a minimum of 6", extend the poly 6" up the walls and and columns. Now someone has to crawl over that fragile substrate in a tyvek suit dragging a 3" hose for the spray rig and a 1/2" line for his respirator. The variable you are not considering is the foam rig; a heated rig using foam components in 55 gallon drums will provide faster application, more consistent yields and a lower cost compared to the smaller 5 gallon component room temperature rigs. If your crawl is more than two feet high it will consume more than one set of room temp components adding down time to the job and increasing the cost. $6500 sounds about right for room temp foam.

If you need the attic space for storage it makes sense to foam it, otherwise cellulose is a great value. At depths of about 16" it has comparable airsealing properties to open cell foam and it can be applied over whatever is already up there, and you get to retain whatever that original R-value was. Cells in the attic will be about half the cost of foam.

As for your convection, conduction, radiation question, that's building science not building code. The code is prescriptive. It says you need R-19, you need R-19 regardless of what insulation you use to get it. 2" of closed cell foam is approximately R-7 and easily outperforms 5" of fiberglass at R-19. In an existing structure you get to do what you want, you only need to follow the prescriptive code if it is new, or substantially new, construction.

Solar is an entirely different topic.

[kurt]

Tom's crawlspace vapor retarder recommendations are good and the rest of it is sound, but it's not necessarily what you need for your particular house. There's a lot of stuff that goes into this, more than blanket prescriptions.

What's the house design? What kind of attic.....overhead, side crawlspaces (like a cape cod), any vaulted ceilings, locations of ducts....all sorts of stuff.

I've found that most insulation contractors are the worst advisors about what to do; they have a product and they sell it. Most, not all, but most.

There's ancillary issues of tightening a house up with foam, primarily indoor air quality. We've been finding that the one's that are tightened up like a foam beer cooler can have serious air quality issues that require an ERV or similar ventilation system to introduce fresh air.

So, it's not complicated, but it's not always a simple prescription. And, I've found the DOE pamphlets to be essentially correct but almost always so generic as to have little actual value in prescribing what one ought to do in a particular structure.

Put up a simple picture of your house as a start.

[David Meiland]

This stuff is discussed all day long at http://www.greenbuildingadvisor.com/

[kurt]

Yes, it is, and the OP can spend their time getting lost in the universe of green options. Or, they can put up a picture and we can tell them in a reasonably condensed and summarized version that applies to their specific property.

Green Building Advisor is fine for you and me, but most beginners don't know where to start.