Hello, all.

I built a shed this summer -- single slope roof. I put on a dark green metal roof. All of this in preparation for building our house next summer -- also single slopes with metal roofing.

It was a very sunny day when putting the roofing on the shed and I was shocked to see how blinding the reflection off the roof was. I believed that the dark green color would minimize the reflection. I was seriously mistaken.

My question is: Has any one experienced, or heard of problems with neighbors complaining about the reflection off metal roofs? I have neighbors across the road from me and would hate to buy and install the metal roof and have complaints. Also, are there better/worse colors? Ways to reduce the reflection?

Any input would be appreciated.

Thanks
North-Cooke

North-Cooke;

a bare galvanized roof , while blinding at first will dimish and become dull in a couiple of years. The dark green will minimize the reflection, but it will also absorb more heat ( not a good thing in summer)

I appreciate the reminder about a dark colored roof being a heat sink.

But I live pretty far north (59 degrees N) and our summer climate doesn't really make this an issue.

North-cooke

I would be surprised if the roof slope and sun angle work together to produce a reflection that your neighbors will see and even more surprised that even if they did, it would be a problem for them.

The reflections from hi performance glass windows CAN be problematic, however.

Bruce

Posted By north-cooke on 22 Nov 2010 01:05 PM
I appreciate the reminder about a dark colored roof being a heat sink.

But I live pretty far north (59 degrees N) and our summer climate doesn't really make this an issue.

North-cooke

Dark colors in roofing also cause extreme expansion, that can be problematic

What Bruce said- unless your neighbors across the street are 100' of elevation higher than your house, the solar geometry and optical reflection rules say they're not going to get a blinding glare off your roof- EVER.

But off your vertically oriented glazing, maybe...

If the roof pitch is between 4:12 & 6:12 the combination of unfavorable solar incidence angle, high emissivity of the finish and convection cooling of the roof would moderate any expansion issues, even if oriented due south. At 59 degrees latitude the angle toward the sun on roofs of that pitch will reflect a large fraction of the total insolation, presenting a very marginal oblique cross section to the sun, giving it a much smaller effective-area for solar gain even were it very absorptive. At 12:12 & oriented due-south you'd be getting substantial summertime gain though- enough to matter. If it's oriented more than 45 degrees off of due south it pretty much doesn't matter what the pitch is, as long as it's steep enough to convection cool (~3:12 or higher.) On that sunny summery day when installing it you probably would have noticed by that burning sensation when you touched it if extreme thermal expansion was going to be a problem, eh? ;-)