Tar and gravel roof


Hi to all

I would like to know if it is ok to sweep the gravel off the roof. Then go over the rest of the roof with insulation board and epdm. Or do I need to remove the tar and gravel both to the wood?

Thank You


Depends on a lot of factors… weight, number of existing roofs, saturated roofing, deck conditions, etc.

If you dont know this, you might want to pass on the job.


I am going to give a price to remove the old roofing. I think it would be the best thing to do. But the owner was trining to save money. I just like to say thank you for all that you do on this web site. You help a lot of people out. This is the place to come if you don’t know something. All of you are good at helping.

Thank You


This is on a grocery store. There is only one existing roof on this store. There is no leaks in the roof. The roofing deck feals fine.


What about a slip sheet?


If it is a big job, then you might want to have the loose gravel vacuumed. we normally scratch the gravel surface of loose stone and debris.
The product that you want to put down is called recover board and it separates the epdm from the asphalt.
If you are going to ballast the rubber, then you can get away with an inexpensive fan-fold 3/8 insulation, and then just put your roof over it, like new construction. If you are going to fully adhere the epdm, you might need a mechanically fastened or adhesive applied rigid insulation that will take the adhesives. I suggest Hunter Panel…you can get it from 3/4 to 4 1/2 inches thick. I guess you could go fan fold with mechanically fastened,

The condition of the existing roof/insulation
system needs to be analyzed before you just cover it over, especially if there is moisture trapped under it. Hope this helps…David


Remove all loose gravel then fasten 1" iso with 12 fasteners per sheet and fully adhere the epdm. If the underlying roof is dry you will be fine. Id stay away from the wood fiber board if you can its garbage compared to iso.


worse things have been done.



iso board or densdeck. fiberboard is crap and absorbs water like a sponge.