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Confused on a few issues? Post New Topic | Post Reply
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Jeremiah Hein
Posted: Feb 14, 2009 09:15 PM
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Confused on a few issues?
I spent a lot of time at the home show dealing with existing homes problems. I don't fully understand how foam would work in a partial system. Meaning most people had issues with the attic and basement/crawlspace areas and were interested in only doing that part. How would the house work with a closed attic assembly on top of a fiberglass attic floor and walls, any condensation issues? Also how would it perform with the basement ceiling sprayed below a fiberglass attic floor and walls?
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mason
Posted: Feb 15, 2009 10:12 AM
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Take the fiberglass off the floor. Spray foam on the walls. You want the interior air to infiltrate the attic. This makes the attic closer in temperature to the interior. As for moisture, vent it outside from your kitchens, bathrooms,laundry rooms etc. It should not be going into your attic. If you leave the fiberglass the attic will be hotter in summer and cooler in winter. Also, insulate your ducts with sprayfoam, This also reduces potential for condensation while making your HVAC system work much more efficiently. It works great to spray the ceiling of the basement if this area is never going to be living space. However if it is, spray just the walls and the sill plate. Fiberglass installed to the floor of an attic in a vented assembly loses half of its insulation efficiency from convective currents in the attic. (source Oakridge National Lab attic simulator testing). So, if you are going to spray foam do at least the basement sill plate and the attic. |
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Jeremiah Hein
Posted: Feb 15, 2009 08:41 PM
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Thank you for your reply. I was afraid you would recommend removing the existing insulation in the attic. |
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Posted: Feb 16, 2009 06:53 AM
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see the post in building/energy/... section look at the "performance" post...real application,,,real numbers,,,real world... dont be afraid,,,"we have nothing to fear except fear itself...." many peeps "cringe" at the thought of having to remove the filterglass or shredded-paper stuff,, remember,,most foamers are not tinkerbell ('ceptin maybe george!) and can not fly about the attic spraying that "poofy foam stuff" hither and thither,,,and,, this is important in any application,,to do a good job with foam you got to see it to spray it,,,we need to see where we are moving around in that attic,,so we dont go through the lid (been there,,done that)...it can be done with the stuff up there but it will be slow,,and time is money,,and your clients want it cheap too,,,right??? you get my drift... and,,in reality (reality=the state of being real,,thanx jimi!!)suckin the crap out of there is not that bad of a task with the right gear and equipment,,,i sub it out...stimulatein the depressed economy...god bless america...(thank you mexico!!!lol) anyway,,, i have a conditioned lid sprayed to a 8:12 pitched roof with the filterglass left under the attics floor deck (between the attic and 2nd level)... we have a temp transducer at the peak of the roof we have one about 3' off the attic deck we have one about 4' off the floor of the 2nd level we have one on the main level, again at mid ht level,,,, anyway,,,, the peak is 2 degrees cooler than the 2nd level the attic deck is 1 1/2 degree cooler than the 2nd level the 2nd level is usually 1 degree cooler than the main level.... stuff works,,,works well,,, walls that work i think it goes,,,, foamed me just like jelly roll,, and it foamed me... |
