Comercial Balasted epdm roof

Long time reader, first time poster.

A family member of mine wants me to replace a roof on a strip mall that he owns.

It is a balasted epdm roof over ISO. Has 12 Ac units on it.

I could use some help from the comercial guys.

I have no problem doing the epdm or the detail work.

What I have a question with is how do you deal with the gravel?

Thank you for your time

Sell it or pay to have it hauled away.

There are companies that will come vacuum it off for you. If it’s fairly clean you may be able to find some lanscapers or land scape supply shops willing to take it, clean it and resell it. Worst case scenario you dump it.

So do you fully adhere the new epdm to the ISO or have new rock brought in? Sorry for the dumb questions. I really could use the work, and would like to have my ducks in a row before I commit to the work.

What type of EPDM roof are you going to install?

Firestone .060


I am not sure about gravel but I just did a 150 square ballasted system and we used LG pavers. I am not sure if that is in you budget but you could look into it.


The way its done is to remove the ballest with a vac truck slice up the old epdm and fasten a cover board. Then install the new adheard membrane.
Or move the ballest off a section install new epdm loose laid and then move the ballest back onto the new area. Repeat until done.

Whats the pros and cons of using the balasted or the fully adhearded on a comercial job(30,000sf)?

Thanks for all the help.


Just watch that you do not overload the trusses when moving the ballast around.

On a ballested roof you can use large panels where on a adheared roof 20’ are about the max.
Adheared takes more materials like bonding adhesive more seam tape and primer t joints insulation and fasteners ect… vs ballested where you reuse the iso with no fasteners and less seams and detail.
An adheared roof is eaiser to maintain and repair.

If you go back with ballast it very simple you move the gravel then move it back. ballasted roofs are usually 1 1/2" river washed stone applied at 10 to 12 pounds per sq foot. make sure the roof can handle the load. I did a lot of them “thousands of square” way back when.

RooferJ is right, get a couple guys, a couple shovels and a couple wheel barrels. Shovel up the stone into the wheelbarrels and dump it on the other side of the roof. Clean off half of the roof, cut out the EPDM. Install the new EPDM and then shovel all the rock back onto the new EPDM. After you shoveled all the rock over to the new side, replace the EPDM just like the other side. Shovel half the rock back onto the EPDM. A good way to measure is that the rock is only one rock thick, which is like RooferJ said, 10lbs a sqft.

Use a gravel broom top push the rock around, it makes it easier.

if you reuse the ballast make sure you don’t score the rubber. that is not a warranty repair and they split open over time and when they start opening up you will be patching every time it rains or thaws. G-tape you ever been out to the Lakewood Facility at Johnson Controls?

Yep, thats what happens when you push the gravel with a Gravely and plow. I never liked when they moved the gravel that way. I think using a shovel and wheel barrel, even though slower and harder, works better.

When you cut out the old epdm I like to put it over the new membrane like a slip sheet before moving the ballest back.
Most of the time the old rock has spalled and is very sharp.

done alot of repairs on that system.
dont like.
not for fl.