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How To Tell If An EPDM Roof Is Wet

How to tell if an EPDM roof is wet.

EPDM (Ethylene Polypropylene Diene Monomer) is a synthetic rubber roofing surface, produced by Firestone, and if installed properly will last 15 - 20 years depending on the amount of direct sunshine it gets.

Key words:  installed properly.

Like any product, if a roofing surface is not installed well or according to manufacturer instructions, it will experience problems, sometimes early on.

Known problems associated with improper installation, or age, with EPDM can include ponding (puddles) which develop because there is not a proper slope, improperly prepared under surface onto which the synthetic rubber is glued, bubbles, tears, poor flashing, and edges which do not adhere properly.

This corner was popped up on this recently replaced front porch roof. 

It looks to have been like that for some time.

Obviously water can get underneath.

We have had a lot of rain lately, and it rained hard the night before this inspection.

In addition to this popped-up corner, there was evidence that ponding happens each time it rains.  Wrinkles could also be seen, and felt, on the surface.

The pond (puddle) had evaporated by the time of the inspection, but its location was evident.  It was clearly evident!










Waiting until after the sun had set and the roof surface was cooled in the shade, any residual moisture remaining under the surface of the roof will stay warmer for a longer period of time.  It virtually shines through to the camera.

Looking at the digital image taken by the thermal camera on the left, the area where water sits over the surface during every rain storm is quite apparent.  The wrinkles at the edge and into the material are also evident.

Comparing the thermal image of that same location one can see the warmer spots, as indicated by the yellow and white areas, which has the same shape as the ponding areas on the left.  That roof subsurface is wet!

Wetness leads to damage, and under an EPDM surface that damage cannot be seen. 

When does it become manifest?  After the damage has progressed enough that the roof sinks in, or collapses completely the subsequent repair is dramatically more expensive. 

To catch it now, in the earlier stages, is much more cost effective!

My recommendation:  thermal cameras, and thermal imaging, can reveal unseen problems during many inspections.  Sometimes multiple problems!  They can show problems with insulation, electrical connections, mechanical systems, moisture intrusion into the house, air intrusion and evaporative cooling.  This home inspector has taken thermal images of all those things and revealed those problems to buyers before the purchase.  That is information!  The home inspector's job is to observe and report.  A thermal image, when interpreted correctly, can provide definitive information, and demonstrate issues in ways that cannot be demonstrated any other way.



Jay Markanich Real Estate Inspections, LLC  

Based in Bristow, serving all of Northern Virginia.

Office (703) 330-6388   Cell (703) 585-7560


Comment balloon 33 commentsJay Markanich • July 29 2018 10:59AM
How To Tell If An EPDM Roof Is Wet
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