Ballasted roofs. How prevalent and how effective at energy efficiency are they?

I dont see a whole lot of these in my area.  Until recently I did not realize that they can be designed to meet 'Cool Roof'. specifications.

 

How many of these do you see in your area?  These are extremely heavy roofs with that much rock.

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Found at the link Hal provided:  "A typical ballasted roof system consists of 10 pounds per square foot (49 kg/m2) of river-rock ballast over an EPDM membrane, rigid insulation and a metal roof deck."
I haven't seen one in years, generally we busy ripping them up & replacing them due to leaks & deterioration - personally I rather see a layer of insulation & a coating, and so would the owners when it comes time to repair or replace it

I agree with you.  I can't remember how long it has been since I have seen one even getting replaced.

 

Here we have the DOE setting standards for ballasted roofs so they can be considered a 'Cool Roof' also along with all the other types of roofs..  This would surely be considered a good thing if it is more energy efficient than a ballasted roof without the coating.  However, ( and speaking only for our roof coating)  there is absolutely NO WAY we would ever give a warranty for this specific application.  Rocks on top of our coating would not phase it's performance in the cold months but would definitrly drop its effectiveness in the hot months.

Spoke to the inventor of our coating yesterday.  He has not seen a ballasted roof in at least 20-years.

Anyone have any ideas where they are still used?????

Apperently ballasted roofs are still used in the UK and other parts of Europe as well as a few areas in the US.  News to me!

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