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Spray Foam Insulation??

Old 03-03-2012, 11:12 AM
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Default Spray Foam Insulation??

Anyone had their existing home or office insulation upgraded with spray foam applied to the underside of the roof deck so the whole attic stays cooler? If so, would you do it again and any suggestions about type of foam for a wood roof deck.
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Old 03-03-2012, 11:19 AM
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Not a big fan of that process for attic insulation, have heard of some mold issue up here in NE with that method. FL may be different.
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Old 03-03-2012, 12:07 PM
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I have never done it under a wood roof deck. I know I've read some issue with it and I simply can't remember what the issue(s) might be. The difference may be in closed cell vs open. I am a fan of whole house envelope insulation and would definitely considerate it with more investigation for your application.

See if reading this helps http://www.finehomebuilding.com/sear...+foam+strategy
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Old 03-03-2012, 12:49 PM
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Open cell foam under the deck works great. We had the insulation blown in at least three years ago. The following pictures shows the temp of the inside of the house, the outside temp and the attic temp. Without the insulation our attic would have been north of 120 degrees on this day in July.








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Old 03-03-2012, 12:52 PM
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get the spray on natural cellulose stuff
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Old 03-03-2012, 01:10 PM
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Yes I would do it again in a heartbeat. My home is frame and built in the 1920's. An old house for my area in Florida. The main living area has a metal, gable end roof.
When I renovated, I used spray foam against the roof sheathing, the original floors, interior walls (soundproofing) and ceiling(soundproofing) of the bedroom and all the exterior walls. I'm pretty sure it was 2lb. foam.
My back porch and garage are under a flat roof and not AC'ed yet. The porch area was foamed and the garage was insulated with R-19 fiberglass, the diiference is amazing, the porch is much cooler. You don't feel the heat coming through the roof in that area like you do in the garage.
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Old 03-03-2012, 01:24 PM
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Originally Posted by Tireless View Post
Open cell foam under the deck works great. We had the insulation blown in at least three years ago. The following pictures shows the temp of the inside of the house, the outside temp and the attic temp. Without the insulation our attic would have been north of 120 degrees on this day in July.
Can you give us an idea of electric use costs after you applied the foam? If you did it while building the house, then how many SF, stories, average temp you keep it at in summer...
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Old 03-03-2012, 01:28 PM
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My Dad is a certified Icynene installer (both open & closed cell foam). I installed as well for several yrs while working for him. If you have any questions, please ask.
Stated earlier about mold issues - NOT CAUSED BY FOAM INSULATION. It's used to prevent that. I can't tell you how many homes we've done on the west coast of FL that had these issues due to the air (moisture) infiltration allowed by inferior insulations. Combine that w/ a vinyl or other type non-breathable wallpaper & you're asking for trouble.
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Old 03-03-2012, 01:30 PM
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Originally Posted by Joe View Post
I've heard that the foam can cause issues with the shingles getting to too high a temperature? Is that true, or even realistic?
This is also more false info. Icynene is certified by many shingle mfr's to be used. If you can make the attic only a few degrees warmer than the living space, that is way better than 180+ up there for the shingles
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Old 03-03-2012, 01:39 PM
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Originally Posted by Joe View Post
I've heard that the foam can cause issues with the shingles getting to too high a temperature? Is that true, or even realistic?
Closed cell doesn't let any heat to transfer into the attic, the shingles get fried in very warm climates.
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Old 03-03-2012, 01:42 PM
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So when you get the roof replaced, and there is rotten plywood as there usually is.

What then?
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Old 03-03-2012, 01:44 PM
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Originally Posted by gort View Post
So when you get the roof replaced, and there is rotten plywood as there usually is.

What then?
Call your installer, they'll bring a touch up kit and spray the void
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Old 03-03-2012, 01:46 PM
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Originally Posted by Tireless View Post
Closed cell doesn't let any heat to transfer into the attic, the shingles get fried in very warm climates.
Please back this up w/ something. I'm in FL - pretty warm here
The problem I have w/ closed cell is IF you have a leak in your roof, closed cell won't allow the water to make it's way through so you can spot the leak - open cell does. Closed cell walls OK
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Old 03-03-2012, 02:27 PM
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Originally Posted by bamaboy473 View Post
Can you give us an idea of electric use costs after you applied the foam? If you did it while building the house, then how many SF, stories, average temp you keep it at in summer...
It real hard for me to quantify the difference the foam made to our house. We have 5400 sf spread out over four levels. When we added the foam we also added an in-line dehumidifier to one zone, humidifiers, electric air cleaners. We currently average around 3,000 kWh per month. The top level of the house feels materially cooler now. Pre-foam, the walls and ceiling upstairs put out radiant heat, lots of radiant heat, during the warm months. Now, those walls feel as cool as the temp of the conditioned air.

One more complicating factor.....after we had the foam blown in I changed the temp settings in all the rooms.....I lowered the summer temp (we shoot for an honest 72 degrees on all levels) and raised the winter temp (74 degrees).....not smart but that is how I roll. The air is cleaner, you don't experience hot/cold spots anywhere in the house, you can store stuff in an attic without worrying about it friggin melting.

I recently spoke to the company that did that work and they told me the current rate to blow in foam is approximately $3 sq ft.
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Old 03-03-2012, 02:32 PM
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I did it to my house in Florida in 07. It is incredible, made a huge difference in electric bill. If I buy another house I would definitely do it again. My attic is 81F in August. We almost never use the heat in the winter. One of the biggest benefits is that your cold air ducts are now in conditioned space. They don't sweat and there is almost no temperature loss from the air handler to the furthest vent.

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Old 03-03-2012, 02:35 PM
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I had been looking into this too for my home in the Keys. I have received so much conflicting information that I got tired of researching spray foam. I am paying attention to this thread and hopefully finding out the real truth with spray foam.
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Old 03-03-2012, 02:37 PM
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I have spent two years researching the benefits versus the costs of spray foam insulation and most of the comments regarding the down sides are either myths OR the wrong type of foam has been used. Closed cell foam should be used as it not only provides about 2X the insulating characteristics than open but also serves as a proper vapor barrier. Roof temperatures, taken in Florida, have been within 5 degrees on a dark shinlged roof for a vented versus unvented space. closed cell prevents moist air from making its way to the wall / roof surface, thus resulting in a proven method to rectify mold issues in vented attic space.

Down side is closed cell spray foam is very costly and the home must have an air exchange system installed. the system cost me $3,500, not cheap. As to leaks and the quoted benefits of using open cell so you can see them, a properly laid roof will not leak. And if moisture can find its way in under those rare cercumstances of high wind, rain and other factors coming together to cause an occasional, then the water vapor can find its way out when the roof heats up on a dry day. Absolute worst case you need to replace a sheet of plywood fi you do have aa leak. I went overboard, knowing I was using foam, and also used a watershield underlayment. I had no leaks with the underlayment alone.

We will be going from 2 100,000 BTU air furnaces and a 40,000 BTU water heater to handle 3500 square feet to a 120,000 BTU FHW system to handle 5,000 square feet. Between the added cost of the radiant system I have installed and the spray foam, payback will be, well, never. I will likely cut my fuel usage in 1/2 but the cost of the system upgrade was very high. Upside is a radiant heated home is very marketable, so in theory one would recoup most of the investment on the back end and also enjoy a very evenly home while living there.

There are many white papers / studies on spray foam insulation. Read the research, not opinions.
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Old 03-03-2012, 03:16 PM
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I had closed cell sprayed in my civil war era home. Worth every penny. I would add that it should be covered by a lifetime style roof, and flashed extremely well. I went with grand manor shingles with a 50 year warranty, lead coated copper flashing and valleys, etc.
If theres a leak, its going to be real hard to pinpoint, so I made sure that the roof was done right.
Makes zero sense to spray the deck of a poorly shingled/flashed roof.
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Old 03-03-2012, 03:39 PM
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Spray foam is the absolute best! Have it throughout the whole house! Great product!
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Old 03-03-2012, 03:42 PM
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howmuch does it cost to get the underside of a roof sprayed ?
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