Need flat roof help

I was asked to help find leaks on this flat roof. I think I did, see pic 2, there were about 5 of these plumbing vents, and four had similar gashes in them, I am guessing it is ice damage.

I still have some questions, pic one is a close up of the roof membrane, those boulders are actually normal sized pea gravel. The membrane looks to be a single layer of roll roofing with granules, then tar on top and then gravel. The flashing was added some time after the roof was installed, its only function seems to be to protect the membrane underneath from damage, flashing is not sealed, just sits on top of the gravel.
Can someone tell me more about this roof construction? It doesn’t seem to sesemble the BUR commercial roofs I am familiar with. The rest of the house had ‘maintenance issues’ too.

Hi Erik,

It’s really hard to tell from the pics of course.
Roll roofing with granules can be mineral paper roofing.
Or it can be modified bitumen (torch down) with granulation.

Tracking down roof leaks is best left to a specialist imho.
They have some very expensive and specialized devices
to “read” what is going on under the top layers.
And water intrusion is so difficult to assess visually.

I would recommend staying away from such work in the future.

I know ice up your way is different from Maryland but I cant see how
a gash like that could be caused by ice on a flat roof.


They need some IR work:D that is how you find leaks on a flat roof;-)

Most likely a snow shovel hit the vent. I fully agree with Tom and Charlie. I would stay away from such work and refer to a competent IR person and go with him and learn.

Picture 1 is showing ‘counter flashing’. It was mainly used to protect the membrane flashing from UV and physical damage. Usually you see it over top of felt and asphalt flashing, but the practice carried over even when they started using modbit flashing. it is not used much anymore as most membranes these day are inherently UV resistant.

Picture 2 is showing snow removal damage, probably from a shovel.

Picture 3, I would guess it is a felt and asphalt roof with modbit flashing, as was the style for a short period of time before roofers were more comfortable with modbit field membranes.

That’s why I was there. IR was inconclusive, no delta T even though the sun had gone down, also it does not appear to be a BUR roof, the reason for my question. But there were those nasty holes in most of the vent boots…

According to the maintenance people the water level after a rain was high enough to reach those holes, plus water was ponding away from the drains, so my recommendation was to replace the boots and consult with roofer or engineer to fix the ponding.

Ya have to get to know Mother Nature she is a big help with Delta T. ??? how long since your last rain before you scanned.

I just bid 3/4 of a million sq ft between two jobs if I get the jobs I will take the rest of the year off:mrgreen::wink:

Ya need to have the roof swept of all ponding water prior to your scan

In some areas you may have to wait for several hours to see retained moisture in a flat roof structure depending on day temp and drop after sunset.

I saw this thread and I wanted to give my insight in commercial moisture analysis as I am a in the process of obtaining my RRC. (Registered Roof Consultant). I’ve noticed that when asked to find the cause to a specific leak in commercial style roof; that it is theoretically impossible to know where the leak may actually be coming from a visual standpoint. (I believe nick said something like this in his response back to you) That’s not to say it can’t be determined either just means nothing is a 100% once it breaches the roof surface. This is because in many cases where moisture is penetrating the roofing material through variable causes can travel through the roof system to the next weak point. (Water can even travel up hill to a degree by materials that waterwick or absorb) Example being absorbed upward in the insulation membranes. infrared is a good tool to help assist in detecting moisture within a roof structure (non-visual). But keep in mind ther are alot of variables to note when using one to detect moisture with in the roof. I currently offer two types of testing for not only detecting the moisture with in the roof but the percentage of moisture with in a roof system. The equipment I use is a capacitance and or nuclear testing procedure. These forms of testing will cost thousands of dollars to purchase the equipment not to mention the fees that might also go along with it. Hopefully this gave you a little more insight to why its something that’s left to a professional. If anyone has any disagreements please indulge me as I’m here to learn as much as possible as well.