attic insulation
#1
02-15-04, 10:19 AM
attic insulation
i live in arizona. i have a pitched roof, flat ceiling. the attic is currently insulated between the ceiling joists. i am wondering if i can further reduce heat by attaching styrofoam/reflective insulator to the above roof joists, leaving air space at low and high end of joist. would this hurt the roof? would it help reduce the heat in the attic? the reason for wanting to do this is arizona's extreme heat and airconditioning venting (also insulated) being in the attic. will also be installing an attic fan to blow the heat out as soon as the sun goes down. (for all those who wonder why arizona does not go on daylight savings time--we want/need the sun to go down)
#2
02-15-04, 11:36 AM
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Welcome aboard! 
Heard of using a foil coated paper in the matter you're talking about, attached to underside of the roof trusses. Reflects the sun's heat & keep attic temps down in the summer. This was in southeastern Texas, only thing I wonder about was the reflected heat adversely affecting asphalt based shingles. Just my $.02
Heard of using a foil coated paper in the matter you're talking about, attached to underside of the roof trusses. Reflects the sun's heat & keep attic temps down in the summer. This was in southeastern Texas, only thing I wonder about was the reflected heat adversely affecting asphalt based shingles. Just my $.02
#3
02-15-04, 01:08 PM
If you go to any of the .gov www on this they say that the foil get a dust on it after a very short time and it is no good. Also Im with Awesomdell here. They have come out with a roof board to use for sheeting on the roof. It has the R/B glued right to it . I dont know what it will do to the shingles .
Now on the fan in the attic . Its not for night. You want a good attic vent fan that works on a tstat all the time. Check the vents you have now is there enough there. That fan in the attic we look at as almost a 1/2 ton of AC for the cost of a small fan runing
We like to tell people to think like this. that roof up there is there to keep the sun ,rain and snow off the insulation of the home and thats all. if its open all around thats just fine. Would more insulation help?
Spent some time in Phoenix and Douglas know it can get warm.
ED
Now on the fan in the attic . Its not for night. You want a good attic vent fan that works on a tstat all the time. Check the vents you have now is there enough there. That fan in the attic we look at as almost a 1/2 ton of AC for the cost of a small fan runing
We like to tell people to think like this. that roof up there is there to keep the sun ,rain and snow off the insulation of the home and thats all. if its open all around thats just fine. Would more insulation help?
Spent some time in Phoenix and Douglas know it can get warm.
ED
#4
02-16-04, 08:52 AM
sounds like just putting the fan in on a thermostat is the best--leave the roof--another question--vent size per square foot???cubic foot??? of attic???--and--fan sizing???
i grew up in a house with a "night attic blaster"--when you turned it on it was strong enough to open vents in the second floor ceiling and really move some air--those were the no airconditioning days--
i grew up in a house with a "night attic blaster"--when you turned it on it was strong enough to open vents in the second floor ceiling and really move some air--those were the no airconditioning days--
#5
02-16-04, 09:20 AM
OK attic fan on a tstat attic sq ft X 0.7 = C FM
Vents old way was 1 sq ft for every 150 sq ft new is for every 300 sq ft . When you have a high R on the insulation.
Now this should be 1/2 in and 1/2 out
Oh ya the night blaster that would be like the swamp coolers they use out there.
ED
Vents old way was 1 sq ft for every 150 sq ft new is for every 300 sq ft . When you have a high R on the insulation.
Now this should be 1/2 in and 1/2 out
Oh ya the night blaster that would be like the swamp coolers they use out there.
ED
#7
02-17-04, 09:48 AM
What you come out with for how big a vent you need for the attic. Say 200"tot. Ok you should have 100" comeing in and 100" going out. Like 100" in the over hang of the home and a 100" up there in the gable or button vents ED
ED
