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Discussion Starter #1
OKay guys I know this has been discussed on here before and I have gone back and read numerous previous posts - However I am still confused! I am looking at adding insulation to my attic. My home is about 18 years old, approx 3,000 s/f. The attic is unusable due to the trusses and my a/c unit and duct work is up there. I have some fiberglass insulation there now, although I know its not nearly enough. I have been contemplating either blowing in cellulose insulation or spray foam (Icynene). I have had a couple of contractors come out - one for the cellulose and one for the icynene and of course I received conflicting advice. Currently the attic is vented by soffit vents, ridge vent, and even a couple of gable vents ( I believe thats what they are called as they are installed in the end peaks). The Icynene guys tells me that he will seal all the vents with the spray foam and then spray the exterior walls in the attic as well as the underside of the roof decking - thus completely sealing the attic into "conditioned space". Now this is contrary to the little knowledge that I have and have been taught by some old school contractors who believe that venting is mandatory. In fact when I presented them with the idea of Icynene they thought I was out of my mind for even entertaining this concept. Anyway, the contractor measured out the space and will work up a quote that I am expecting tomorrow. His suggestion was to not only do the attic but also the sill plate in the basement. He also told me to not consider cellulose in the attic since my a/c unit is there and that I would not have 14 inches of space between the bottem of the unit and the floor joists to get the proper level of cellulose and that if I ever needed to service the unit (or anything else in the attic) it would be a nightmare with the cellulose since there is no walking space.

Now the cellulose guy comes and say's no problem this is a perfect application and I can blow in 12 inches of cellulose, ensure that there is proper baffling at the soffit vents and even construct a retaining type wall to protect the a/c unit. Additionally since my master bedroom is above the garage he says he can drill a small hole in the garage ceiling and blow in cellulose to help keep the bedroom warmer as well. He was also very skeptical on the idea of sealing the attic vents and what that would do to moisture in the house and its effect on the shingles.

I am so CONFUSED! To top this off I am planning on installing a new roof in the summer, going over the existing shingles since there is only one course there.

I am expecting the Icynene to be significantly higher in cost and will have to weigh out the return on investment - I am just so confused on the theories of which is better and is having an unvented attic in Northeastern New York really smart?
 

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An attic needs ventilation. If this is a single story you will need to have moore vents(raft-r-mates) from the soffit to the top of the insulation and if it's a 1 1/2 story then moore vents in the sloped part of the celing . For a full 2 story you do the same as a single story. The spray foam doesn't normally show a return on investment for a 1 or 2 story but with a 1 1/2 it will eliminate alot of ice when filled right up. You HAVE TO have ventilation though. The shingles will get hot in the summer and there has to be a way to cool them. If you really want to warm it up get it to at least R-42. Make it R-60 if you want to have an even lower heating and cooling bill. The guy spraying the icynene must own either a roofing business, and/or a fuel company. You will have venting problems and it will cost you more to heat your house. Basically I'm saying you'll be wasting your money with the spray foam and that guy is lieing to you.
 

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Discussion Starter #3
Thats what I was afraid of - its a 2 story home and I figured the attic needed to be vented, although he says it doesn't and even in some of the posts I read here the claim is that the attci becomes a sealed conditioned space.
 

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Actually, the icynene contractor is correct in his remarks. It sounds like he is going to turn it into a hot roof. Shingles are now rated for this and warrantied and it is possible to do what he's doing. It wouldn't be my recommendation though. The cost is far higher and cellulose blown in is good bang for your buck...make sure they install wind washing. Also, in the case of the rim joist you should the icynene because in that application it is the only thing to use in a cold climate.
Another option would be to have the icynene contractor just spray inbetween the ceiling joists. This would be a lot tighter than the cellulose, plus there will be a lot less material used and therefore cheaper.

Josh Jaros
 

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Discussion Starter #5
Thanks for the reply, the Icynene contractor said he wouldn't spray the joists in the attic, that it had to go to the roof decking? I will compare the two quotes when I get them. What is wind washing?

I will look into the hot roof also, not sure if this equates to me if I will be shingling over the existing roof.

I also asked the Icynene contractor about just doing the sill plate in the basement but he said that the job would be too small and maybe not worth it cost wise, I asked for a quote anyway so we'll see what he comes back with
 

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Discussion Starter #6
Just to be clear on my previous post - the Icynene guy said he wouldn't spray the floor joist in the attic, only the underside of the roof decking
 

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just that it was not the "proper" installation of the product
More than likely he just didn't want to deal with removing the old fiberglass since you can't spray the foam on top of the old fiberglass. He just wants to come in and start spraying. Which is also why he's just going to spray the vents closed rather than remove them. When you go to reroof and find the ridge vent glued in place by the foam you are going to have a heck of a time removing it without damaging/cracking the foam insulation. If you crack the foam you've just lost the airtight seal which is one of the key advantages of the foam.

Both the foam and the cellulose are great products and either will work fine if applied correctly which means that the most important thing is selecting the right contractor.
 

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Discussion Starter #10
I thought we would have a problem with the ridge vent - I'm leaning more and more to just going with cellulose
 

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One of my previous posts....
Unless you incorporate a Hot Roof System. My brother-in-law did this to his new home a few years ago and he's completely satisfied with his choice and how energy efficient his home is.
IMO, if you want the bang for your buck, then go for the cellulose. If you're in it for the long term savings and can afford it, then go the spray foam.

Also take into consideration this years Tax Credits 10% of cost, up to $500.

The foam is perfect for the basement rim joists. I think the contractor maybe indicating a back out for that "small job" basement project trying to get the whole quote. With the economy the way it is, I'd think he'd be trying to get what he could. You might be able to use this to your advantage to get a better deal?

Best of luck. :thumbsup:
 

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Discussion Starter #12
Thanks, I was expecting the quote on Monday, it still hasn't come so I'll give him another day. I asked him to split the quote between the attic and the rim joists in the basement. I'm thinking of doing it there since it seems like a good place to save, however I have no idea how much it is going to cost - it could blow me out of the water!
 

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Discussion Starter #13
Okay just received my Icynene estimate - Was given 2 quotes - one for an R-20 for $5,900.00, the other for a R-30 for $7,400.00. The R-20 price seems reasonable, however I am not sure if it makes sense to increase the R value to R-30? The gable walls and vents will only be insulated to an R-14 and the sill plate in the basement will be an R-14.

I thought the attic was supposed to be at least an R-40? What do you guys think?
 

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Your ductwork should be insulated as much as possible. I would go with the crib around the a/c unit!
R40 is the standard today! In my house, although I had cellulose blown in the walls, I opted for fibre glass bats run across the ceiling joists! They can be lifted for maintenance and then returned to there place!
There are some that argue that attic space doesn't need venting, I've never seen a case where it caused any harm!
 

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Discussion Starter #17
There is a big debate on whether the attic needs ventilation. Although batts are easy to move and work around, it seems they are not as efficient as the icynene or cellulose. I'm not sure which way to go, and although I am investigating and trying to get informed - the more confusing this is all getting
 

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Meth, i would be very scared about having an unvented attic in your climate. These may work in a dry climate like Arizona. Also you have an older home that likely has many warm air leaks into the attic, the moisture the warm air carries needs to be disposed of by some mechanism, other wise it will eventually find its way through the semipermeable foam and condense on the roof decking. This will wet the foam and accelerate the rate of condensation. I would use the blown in and do what you can to seal all air leaks into the walls and ceiling. There are a large number of ways to do this sealing. time consuming but well worth the effort.
 

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Discussion Starter #19
Thank you for the feedback and advice. Your concerns about moisture and ventilation validate my own concerns. I am starting to get more and more nervous about the Icynene. I'm thinking about using blown in cellulose around the majority of the attic, then using batts around the 2 air handlers in case I need to work on them the batts will be easier to move around. I can then wrap the handlers with an insulated wrap blanket. The big problem is addressing all of the current warm air leaks, I guess I need to pull each batt up (that's currently there) and look for potential leaks and then spray foam to seal them. Big pain but I'm sure its worth it. I will hire someone for the cellulose so maybe they will do this service for me as well. I'm sure it will still be a third of the 7k icynene cost. I would really like the basement sill plate sprayed with icynene though and this guy won't come out for such a small job. Its a 300 dollar line item on the initial quote, to just do the sill plate he wants 1000 as his minimum fee
 

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I agree with what's been posted by the others. In your situation (which is basically the same as mine), I would go with the cellulose. If I were building new and had the cash, I'd go with icynene. I've seen it done as the contractor suggested and it works very well and seals the house up well, but IMO it's something to be done on new construction as part of the design of the home. Adding it after the fact... nah, I wouldn't personally do that.

We just built an addition and I have the same attic situation... going with blown in for both. Good price and effective, plus the house was designed for it.. ridge vents and sofit vents.

Good luck!
 
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