What does a foam insulated sealed attic look like?

[amusingisthedawn]

I can't believe how many videos promote spraying directly onto the roof deck. You need a radiant foil with an air gap...THEN you can spray away...spray foam doesn't do anything more than batt insulation except seal a few more air gaps. It isn't magic.

[chechnya]

What is the difference between spray foam vs. foil barrier vs. spray aluminum barrier?

[HomeEnergyNow]

@chechnya Spray foam is for conductive heat. Most heat transfered through the roof is radiation, not conduction. So applying foam to a roof deck is retarded for many reasons. Foil is 97% reflective, meaning the heat from the roof is reflected back out, and the temperature of your ceiling/insulation is reflected back to the ceiling. The coatings are usually around 75-80% reflective, they are designed for attics that would be difficult to foil. Foil/aluminum is more for hot sunny climates.

[d1incharge]

Here are some #'s from the last ten houses we put up that I tested last year. Avg .017$/sqft/month to heat and cool.......What it would have cost to use foam .007$/sqft/month just in interest. Now to pay towards the 4250$ cost of spray foam to find a return on investment date, lets say you had ZERO heating and cooling costs, it would take 11.6 years for my avg. home-buyer to pay for the cost of foam EVEN IF THEY HAD USED ZERO HEATING/COOLING. Nice ROI, the secret to new const.'s last choice.

[Enviropro8829]

where are these homes? SOunds like the climate is 72 degrees year round. If you are located in a moderate climate the type of insulation used will have little impact on the cost savings. Your comments are based on your personal experience in one climate, which does not apply to all climate zones. Moderate climates do not have the same issues or payback as the Hot/Humid or Cold climate zones. You never answered my question on how you acheive a R60 with blown in products.

[d1incharge]

@Enviropro8829 I have built from Texas up to Kansas. From slabs to basements, hvac w/in and hvac outside of the envelope, in three different climate zones.. Kansas was where my numbers came from, I had a personal house in one of the breeziest areas, and it is NOT a moderate climate. The kwh rates there are good, but the ROI w/foam ALWAYS ends up the same. To get R-60 depends on the loose-fill, I just looked up certainteed, it is 22" blown in for R-60. Is that even possible with open cell?

[Enviropro8829]

to responed to d1incharge the 2009 IRC does not limit the area of a cathedral ceiling in a home if you provide compliance to teh energy code via the performance method. The performance method is always used when spraying foam to create an unvented attic assembly. Please check your facts....

[d1incharge]

@Enviropro882 Now, instead of just having to pay WAY more for foam, now you have to pay more for an Energy Star Rater just to bypass the codes? I can see the Return On Investment getting closer !!!! HAHAHA. Just as long as your customers are rich and ignorant I guess everything will be fine. What you said in lame persons terms...........You can pay more for inferior insulation, and still pass codes, as long as everything else energy related on the house is superior to balance it out, correct?

[Enviropro8829]

There is no need to hire a HERS rater to show compliance. The insulator is responsible to show compliance via REScheck. Your comments again show that your are lacking in general building science or code knowledge. Everyone of your comments is incorrect.

[d1incharge]

@Enviropro8829 I am lacking knowledge in the department of how to make this insulation pass new codes, but glad. How many insulators are there that have or can run RESsoftware? It is a rare, good find, probably more expensive(so I am not far from correct)I use RESdesign w/numbers such as R-60 blown in on the ceiling vs. r-30 or less(plus bringing the attic space in as conditioned) foamed roof deck, the later is inferior energywise, more expensive, and makes it tougher to use radiant barriers

[Enviropro8829]

You have many things to learn my friend, please put your bias aside and open your mind to the science of the truth.

[d1incharge]

@Enviropro8829 You should try building, and watching costs start to heavily outway the savings. You should learn more about codes and local govts., since they change from place to place. Most of all, you should prove that somehow, if you create a larger conditioned space, use a lower r-value(no I dont want to get into the foam industries biggest BS arguement with the ASTM) somehow this will save people money? Greater envelope.......greater ft3 to condition...less r-value....lesser bills?

[Enviropro8829]

You talk in circles because you have no facts just opinions. How do you acheive an R60 with a blown in material on the floor of an attic. Please don't tell me it is the number of inches of the material X it's Rvalue at 1 inch.

[d1incharge]

@Enviropro8829 In my defense, these codes are somewhat new. But as an avid user of RESsoftware, and over a decade of building/home energy experience, I have no doubts that spray foam is a spend a dollar to save a dime industry. I have seen non-foam customers in 3000sqft homes with 42$/month heat/cooling costs. Many will pay that JUST in the extra homeloan interest for foam, while still paying to h/c there house! My neighbor has foam, .009ACH, highest bills around, it is an unhealthy energy hog

[Enviropro8829]

The performance based method for compliance is not new more than 10 years in the IRC code, for someone who thinks they understand the code or home energy performance you have proven once again that you do not. I suggest you spned less time comenting on things you now little about and more time studing building science and the principles of basic heat transfer. How many ways does heat transfer? Do you even now the parameters of the ASTM test for R-values? I think not?

[d1incharge]

I know you probably dont want to hear any more of it, but the 09 IRC codes have changed to prove my point with the cathedral style foam envelope r-values......."Cathedral ceilings tend to have limited insulation and can account for large energy losses.(r-19) The IRC has now limited the size in which you can build cathedral ceilings to either 20% of the entire ceiling area or 500 sq. ft., whichever is less." BOOOYAAAAAA

[d1incharge]

How thick is that stuff? By the looks of the 2x6, maybe 2x8 rafers, it would be 6-8" thick! That would be great, but isn't open cell foam 3.6/inch making your total R-value= 21.8 - R28.8 maybe give you the benefit of the doubt and say it is R-30, aren't the MINIMUMS R-38?? recommended R-49??? And how many more cubic feet of air are you having to condition now, by bringing the attic into the envelope? Do you test homes when you are done to make sure they are not too air tight?

[SteveJRosenbaum]

d1incharge,

Good questions! I have contacted the manufacturer of the foam, and Streetman Homes and asked them to respond. In addition, we are going to address your very questions, live on our radio program Sunday morning on ESPN Austin. I invite you to call in and be a guest and pose your questions on the air.

Let me know,

Steve

[HomeEnergyNow]

Are you still on the air? I would love to help put an end to this temporary trend here in Austin, I have seen the spray foams come and go in many places, somehow it is still surviving in Austin. Somebody needs to get the information out as to why spray foams need to stay out of residential construction for energy, and health of the occupants. Here in Austin to bring in fresh air they just poke a hole and run it to the return. Energywise no gains.Healthwise, way more risk of not getting fresh air