Q&A - Can You Put Rocks on a TPO Roof?

Georgia homeowner asks about the possibility of putting rocks on a TPO (thermoplastic polyolefin) roof. 

Chris, from Georgia, asked the following: 

Can you put rocks on a TPO roof? If so, why would you? 

Roofing expert, Brenna from Innovative Roofing Group, had this to say in response: 

Technically yes, you can use rocks, or ballasts, on a TPO roof in conjunction with a slip sheet, but it's more likely that you'll see them previously installed than added to a roof afterwards. They're typically used as a cost saving measure, or a way to provide protection to the existing roof system. The ballasts weigh down the membrane which means fewer fasteners and less adhesive is needed for support.

Roofing expert, JD Gustavel from Bone Dry Roofing Company, replied: 

Yes, you can put rocks on a TPO Roof.

Personally, I had a special circumstance with a job where a radio tower was present near the roof system. Rock was installed on the TPO Roof to safeguard from potential icicles that formed during the winter months. These icicles could have fallen and damaged the roof system without some sort of protection. Mainly rocks can be used on a TPO Roof to safeguard from potential damaging weather.

Roofing expert, April from Pittman Waller Roofing Company, said this in response: 

You can put rocks on a TPO roof to act as a ballast and provide UV protection; however, it is rare and not recommended by Pittman Waller Roofing Company, LLC.

Roofing expert, Jordan from Elite Exteriors, had this to say in response: 

Gravel is not recommended on TPO roofs. Tpo roofs typically aren’t designed to hold the extra weight and adding gravel adds no benefit. 

Gravel is typically used for two primary reasons, one to protect underlying roofing materials on built up roofs and two to secure/weigh down roofing material on single ply flat roofs. 

This last part isn’t fact, but in my experience TPO needs to be clear and open. It is recommended to clean off debris and dirt to prevent puddling and premature deterioration near seams. 

Continue the conversation in our Forum!

Have a question? AskARoofer.

Find your local roofing contractor in the RoofersCoffeeShop® Contractor Directory.