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-   -   How to tell if attic/shingles are getting too hot (http://www.diychatroom.com/f9/how-tell-if-attic-shingles-getting-too-hot-11021/)

Malcolm 08-26-2007 01:11 PM

How to tell if attic/shingles are getting too hot
 
I want to make sure that my roof isn't getting too hot. I took the proper measures to properly vented. What temperatures are considered problematic in attics and shingles. I guess I'm looking for a temperature that would start to cause shingle failure.

Docfletcher 08-26-2007 08:29 PM

Check this page, it has at least some and possibly all of the information information you seek.

Sorry i could not get the link to post but here is the story.


When it's hot outdoors, it's hotter in your attic. A hot attic is bad for several reasons. High temperatures inside your attic shorten the life span of shingles. Excessive heat deteriorates items you store in the attic and can cause moisture problems in your house.

Take its temperature. Hang an outdoor thermometer in your attic, making sure its range reaches at least 130 degrees Fahrenheit. Hang pencil and paper next to the thermometer and record the outdoor and attic temperatures for several hot days.






Note excessive heat. If it's 90 degrees outside, the attic temperatures shouldn't exceed 110, according to home inspector Jamison Brown of AmeriSpec Home Inspection Services in Poquoson. "However, more often than not, around here I find attic temperatures to be in excess of 125 on a 90-degree day," he says. "This overworks the air-conditioning equipment, runs up the cooling cost and shortens the life of the roof covering, or shingles."



Ridge vents help. Excessive heat can escape through ridge vents, which are shingle-covered openings in the peak of your roof. They can be installed on new and existing roofs.



Assess your insulation. Attics can be insulated against heat and cold. Ask an insulation specialist to evaluate your needs.



An attic fan may help. "Generally speaking, if you have a ridge vent and a roof fan, the fan draws its air from the ridge vent and not from the lower air intake ports in the attic," says Brown. "That being said, most of the time a fan would be of no value along with a full ridge vent. Now if the ridge vent is only partial, or if the attic air temperature is excessive (20 degrees higher than the outside air), fans may prove beneficial."

the roofing god 08-26-2007 08:55 PM

SOMEBODY`S LEARNING!:laughing:

Clutchcargo 08-26-2007 09:26 PM

Quote:

Originally Posted by Docfletcher (Post 59816)
Note excessive heat. If it's 90 degrees outside, the attic temperatures shouldn't exceed 110, according to home inspector Jamison Brown of AmeriSpec Home Inspection Services in Poquoson. "However, more often than not, around here I find attic temperatures to be in excess of 125 on a 90-degree day," he says. "This overworks the air-conditioning equipment, runs up the cooling cost and shortens the life of the roof covering, or shingles."

Is that 90F in the sun or in the shade?

the roofing god 08-26-2007 10:50 PM

Ed is the resident "technical"ventilation expert here:yes:

Docfletcher 08-27-2007 12:13 AM

True enough:yes:

Ed the Roofer 08-27-2007 08:30 AM

I am in the process of conducting a ventilation and temperature experiment which will be written about in a ventilation newsletter in the near future.

I have ordered several wireless thermometers and am placing them at verious positions, high in the attic, by the eaves in the attic, on the sunny side roof top and due to the comments here, maybe also in the shaded portion as well.

These temperature readings will be taken 3-4 times per day for at leasty 1-2 weeks before we do the job.

New temperature readings will be taken after we install the Smart Vent for proper intake and the Shingle Vent II for proper exhaust.

The ambient temperature from out side readings and the National Weather Service will also be recorded.

The differential in the before and after scenarios will be recorded to show the variances.

Results should be available in about 4-6 weeks.

Ed

Clutchcargo 08-27-2007 09:25 AM

Thanks Ed, I'm looking forward to the results.
It would be interesting to know the air flow through the attic at various temperatures as well. I would imagine that would be a difficult measurement, however.

Ed the Roofer 08-27-2007 09:38 AM

It is a large bungalow with a 7/12 or 8/12 pitch and a staircase to walk up into the attic.

The thermometor placements should actually be quite easy, but I have to make sure the HO writes down the results at the designated times for the discount I am giving to her.

Ed

Big Bob 08-27-2007 10:11 AM

ED, sounds great!

track Rh and Bar pressure if u can. I think you will find interesting correlations ( effect on convection currents) also hip vs gable ?

Ed the Roofer 08-27-2007 01:16 PM

It is hip style with multiple dormers and a significant amount of ridge lengths.

Are you speaking od a barometer?

Would I need to only place one inside of the attic or also another one outside for any additional statistics.

I am going to Radio Schack later today to order the wireless thermometer.

Please place a link for any additional products for recording these fluctuations that you can think of, if you have time.

Also, what interesting correlations do you think that I will discover?

Ed

Big Bob 08-27-2007 02:13 PM

High Rh/ attic will stay hotter longer.:furious: (Rh is a big factor in insulation values)


NWS info should be ok

exterior site info better ( if the vent folks are helping $ wise on your project)


By tracking you will be able to isolate this variable / compare similar temp & Rh before and after.

barometric pressure changes effect convection currents.

other info to collect might be wind speed and direction. Higher wind speed should = shingle cooling, will this transfer to the attic?

Track rain/ big cooling factor.

Ed, I am glad to see you riding high in the saddle after your hospital adventure.

Best of luck with this.


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