I have this idea for roof insulation.....

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  #1  
Old 07-20-20, 01:05 PM
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I have this idea for roof insulation.....

So it's hot now in NJ and the weather is foretasted to stay in the 90s with no rain...just the Sun beating down on us.
I was wondering....I have a roof in good condition but it's darker in color....I imagine the Sun is heating up the roof, and even with my attic insulated with R40 is still getting to brutal temperatures which surely impacting the inside temperatures and making my central air unit work harder and longer etc....

So...how about this; I can get a few large...say 4x10 ft pieces of radiant bubble insulation - I am talking about that very light silver foil material and just attach it with several dabs of glue to the shingles to form a large reflective surface.

Now - this would be only a temporary "experimental" solution - after several days or if winds pick up - I would go up on the roof and take it off.

Few concerns:
What glue to use to ensure that it doesn't damage the shingles ?
ANy risk for air traffic (though I barely ever hear an airplane) that such large reflective surface may blind the pilot?
Any other comments....??
Of course I know this is just temporary and not a real solution..I realize it will look crazy for a few days ....
However, for the 2-4 days my idea is to measure the amount of heat being reflected and reduction in A/C usage.

Thanks!
 
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Old 07-20-20, 02:04 PM
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If the slope of your roof is not excessive you might want to weight down the reflective surface. If you use dabs of glue you need something adequate to hold the material and yet release in a wind situation before it pulls the roof tabs up. unless you cover your entire roof how will you determine what value your experiment has?

Doubt air traffic would be affected but do you have any roadways in view that could be?
 
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Old 07-20-20, 02:57 PM
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My house is positioned East - West....meaning one side of the roof facing East is "heated" till about 12 noon while the other side stays in relative shade.... and then as the Sun goes over the house, the West side is exposed.
I am thinking to cover only one side.... and compare to previous days reading as well as side to side (from 10AM till 2PM = assuming 2 hrs before and 2hrs after the noon should be equally hot in terms of Sun radiation.
Grass on both sides so don't need to account for radiant heat reflecting off of the surface - which would probably make the 12 to 2 reading higher than the 10 to 12).

pretty crazy stuff..... if you guys haven't guessed it - I am a scientist by education.... and people tell me I am very analytical.... but this COVID19 and just staying at home 90% of time , I guess, is pushing it to the limits ...LOL
 
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Old 07-20-20, 03:23 PM
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Here is an excerpt I found discussing the affect of attic temperature on a home's cooling needs which I think applies to your hypothesis.

Professor Bill Rose, Research Architect, Building Research Council-School of Architecture University of Illinois, found that “in roof cavity assemblies which are poorly insulated (less than R-10), ventilation can reduce cooling loads by 25 percent. However when these assemblies have thermal resistance greater than R-25 ventilation has a negligible effect.” If an attic is under-insulated the solution is insulation, not attic ventilation.
 
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Old 07-20-20, 05:11 PM
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Pilots quote from Bill Rose is good.



As for experimenting you and I are a bit too late to be testing anything new. So much research has already been done the problem becomes digging it out and interrupting the research language. Here is a link on a presentation by Danny Parker, another name to watch for. I think it is the 4th image that shows the bottom of the rafters covered by the reflective foil. I would prefer that to on top of the shingles but he may also have some of the numbers you hope to gather.

https://www.coolrooftoolkit.org/wp-c...-Cool-Roof.pdf

Bud
 
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Old 07-20-20, 05:36 PM
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I don't know what the point of "experimenting" would be when there are already well known studies that have been done on the subject. A white roof will be cooler than a dark roof... metal roofs are cooler than asphalt shingled roofs and a white metal roof will be cooler than a galvanized metal roof. And the best roof color and type (if you are after the most reflective / coolest attic) is white tile.

https://www.greenbuildingadvisor.com...our-roof-color
 
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Old 07-22-20, 09:00 AM
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the idea came from the TV ads for Sunsetter - the retractable awnings.
Yeah...there are several types of shingles and roofing materials, but rather than replacing the entire roof....could I potentially achieve huge savings by simply having a $200 worth of reflective foil which I could roll out over a large portion of the roof and safe hugely on electricity.
I am not talking about doing any major upgrades, roof replacement, major labor or materials expense.
Just simple reflective foil rolled over the roof.... which in my opinion would be WAY BETTER than actually any new roof materials from Energy efficiency POV....of course the only shortcoming is that such foil is NOT appropriate as a permanent solution....
 
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Old 07-22-20, 10:41 AM
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With R40 in your attic the house below is so well isolated from the attic's heat that anything you do in the attic has little to no affect down inside the house.
 
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Old 07-24-20, 06:04 AM
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Dane - that's an interesting statement....few papers I looked over said that in extreme heat (90F or above) the insulation while protecting the rest of the house will transfer some of that accumulated heat, up in the attic, down.
There were some numbers from AZ or NM showing attic temp close to 170F....and the claim that no amount of regular approach to insulating would be able to prevent heat transfer down to the actual living spaces
The idea was to add reflective material between the rafters to help transfer the radiant heat back out to the roof again ...so you effectively reducing the attic temp. by as much as 25F.
 
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Old 07-24-20, 06:49 AM
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Hi Paul, just following along.

You said "There were some numbers from AZ or NM showing attic temp close to 170F....and the claim that no amount of regular approach to insulating would be able to prevent heat transfer down to the actual living spaces"

That statement isn't entirely correct. The heat transfer will be reduced with additional insulation but it will never go to zero and reducing it is what you want.

R-40 is a modest amount of insulation, think code level minimum. But codes are based upon many factors like cost of insulation and cost of energy and nothing prevents you from adding more, other than total weight and your wallet. Also the type of insulation contributes to how much attic heat makes it way down to the ceiling below. Fiberglass is probably the worst as light can shine through it and that means radiant energy as well.

As for radiant energy a reflective surface below the roof deck or bottom of the rafters would help.

Bud
 
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Old 07-24-20, 06:59 AM
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I have not read any papers but you seem determined to do this so do it.
If wind gets under it then you may wake up in Kansas.
Or if you do not only want to save air conditioning costs but actually make energy cover the roof in solar cells.

As far as attic temperature did the attic have proper ventilation?

Also heat rises so the heat transfer to the room would be minimal, in my opinion.
Where it does make a difference is in the winter with heat conducting up and out of the room.

 
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Old 07-24-20, 10:34 PM
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And whatever you save in energy costs by covering your roof in foil could be kept in a separate account for future hospital bills when you fall off the roof.
 
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Old 08-08-20, 03:56 PM
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OK , Handy Man - Good Jack of most trades Not an Expert in any one , but My Attention to Details &
Memory like Elephant as to Even the Vary Words and How - those were Stated on said Day . . May Helped Me
During Inspection of Jobs Sites & Products : Involvement & Interactions with Clients , Contracts Details , Persons Involved , Time of Day etc. Are very Good . . enough about Me ..

I gave a Quick read to this ? about Foil on Roof - Yes it would make a Large Difference to Tune of 40 Degree
Even If was R48 in Attic .. " Heat Radiating is Like a Toaster " Entire Roof Assembly , Wood , Metal Brackets
Nails , Screws , Insulation , Duck Work , an Approx 5-6 Tons of Asphalt & Under Lament for Grand Total
approx 10 Ton . .Sun Bakes in BTU's for 6-7 Hours from 8:am to 3am maybe even 5Pm If You Home is Higher then Surrounding Homes or Sun has a Clear Shot at Roof . . Then Only Then does some Cooling with Wind and Shadows start to Pull BTU's in other Direction .

It will take 7-9 Hours for Cooling or Normalizing to take Place - Unless Your Roof is Ventilated Very , Very Well
Plus Night Time Temp. Drop is Fast , like 12 Degrees by 9am

Only Then will the BTU's ~ Start to Run the Other Direction .. Now that entire Assembly Plus "Your Ceiling"
Drywall which Add's in another 3 Ton - has to Normalize . . As Most of U probably have Your Stat on 75 ~77
Certainly 135 Degree in Attic on a 12/6 Roof is NOT Unheard Of . .

I Site an few Examples - I Completely redid a 2.5 Story Victorian Top to Bottom .. 102 Year Old Building ..
Today it's 120 Years Old .. 17ft Walk Up Attic with a Landing x 5ft wide Stairs - Attic Floor 2 x 8's Covered with an Inch of Wood - Stuff with 2.75 R Inch Blown in , They like to Quote 2.95~3.15R so with Wood
Easily Good R21 when most these Old Homes were lucky to have R13 . . 12/12 Roof 34 Sq. & 100% Ice Shielded ..3 Big Sky Lights

10ft Ceiling in Late afternoon Rooms upstairs would be 78-80 just a few Window Units for Entire 3000 sq. ft
6 Bedroom 3 Baths , NOT Counting Attic Nor the Basement .. - It would take until Midnight to Cool Off . .
In Mornings Hot Summer - wouldn't need Window Units - Until afternoon 3PM ..
Added Much Higher Ventilation ( Ridge Vent & 6" Holes covered by Grills ) all along Sun Exposed Side ..
24" Soffits on this Home with 1.125 Thick Wainscoting on under side of those Soffits - that took some Doing ..
End Result ~ Cooler Attic by 15-20 Degree - Home Cooled Off Way Faster and so A/C Units shut off earlier . .
more Often ..

Sorry for the Short Story - that has Turned in Novel : LOL

2nd Example :
Another Home 875 Miles Directly South Near - Smokes - so some Shade & Coolness compared to Texas . .
Even thou there are Two Huge Oak Trees , afternoon Sun is Relentless & R44 Placed in Attic Up from R14 in Attic - Only Delayed Heat Waves - coming into Home .. Even Ground - 6ft Down gets Warm in South ..
Thee Eventual Heat ( Radiation ) Driving it's way Down into Home .. after studying this issue for some time
Ridge Vents would Only Help a Little - as many Homes in South are Hot Boxed , to Keep Out Bugs & Rodents ..
Plus Humidity ~ Condensation Issues ~

This Home only 40 years old - seem to do Worst then Victorian ..
Looking into Cool Roofing - it is a Must in South - Plus all Cities down here have a Huge Issue with Heat Island Effects

I could Elaborate on Even more Reasons .. these Homes are like this after 167 Home Inspections in this Area along .. many are Way Worst then 2nd Example I'm Describing ~ It's No even a Dark Roof , it's Light & Medium Gray . .


Leaving Window Unit on Upstairs and doing IR Readings on Ceilings & Walls - Temperature Invasion
Say that Again :
High Temperature Invasion from Attic is NON-Stop - until - 11-12PM sometimes on Warm Night
2:30Am in Morning - It's just Plain Nuts - How Much Energy these Homes in South Burn !

That said I have Lowered the Electric Bill from $320 a month to $154.00 being Highest . . 2 Bills Before & After .
Most are around $110.00 - Full Basement , No Attic ( 5-6ft ) high is all , 2 Baths Small Soffits . .
Way to may Old Windows . . That $110 also includes ~ Water & Gas !

Summarizing By all Means do as Much as Possible to Lower Your Bills & Be More Eff%
Cool Roofs will Not Hurt You even in Northern Adirondacks ..

Only REALLY Good comment from up above was the Solar Roof - Placing Solar onto a Roof will Shadow the Entire Area - like the Ones that Mounted with 4-6 inch Space and Easy Removal - encase Roof has to have Maintenance Future . .

Buy Yourself a IR Gun - those are so Cheap Now . .
Invest in Single or Double Bubble - Dual Foil Sided have it Placed at Lease 1.5 Inch away from Under side
Roof Sheeting .. I just Bought Two Rolls 200ft Long x 3ft wide ..
I also ~
Have some Other Data on Back Porch that was Done in a Manor to Study the Very Effects asked about Talked about in this Thread ..

See Ya on the Cooler Side .. I have Planted 172 Trees & Bushes on Our Properties over last 40 Years
Donated to get 1 Million Planted and just Last Yr. took out into Wild 4500 Oak Acorns in several Area's all over the Smoky's , Blue Ridge Park Way , along Several Rivers . .
 
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Old 09-11-20, 03:11 PM
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Thanks for sharing..... glad to see somebody appreciates the idea.... For me it was more of a concept / test validation....
I don't want to hijack my own post - but in all honesty..... I really think the majority of Construction /Materials companies are sort of Monopolies.
Surely they invested a LOT of money into production, distribution and installation of their products but I just can't believe there is SO LITTLE innovation and progress.
We still use wood and gypsum wrapped in a paper to build majority of our houses....
I know for a fact that far superior materials are available and IF MASS produced would be parity in cost.....just not enough volume and competition to accelerate the progress.
I also recognize that techniques and materials have improved considerably but comparing to progress in other industries..... still way behind
 
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Old 09-18-20, 05:34 PM
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Hey - Paul how did Your Experiment Turn Out ?
 

Last edited by XSleeper; 09-18-20 at 06:10 PM. Reason: removed fluff (non-beneficial)
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