Not understanding this and being frank, I call this an architectural flaw - and poor roof design.
1. Lots of square feet of roofing surface.
2. A steep roof on both sides of a long valley.
3. The valley directs that water right at the house.
4. There is faux stone.
5. The gutter is small.
So, during a heavy rain we have hundreds of gallons of rushing water, hitting the corner of the house, and overwhelming a small gutter.
What happens when that happens?
Damage, and then, sooner or later, the water will make its way inside.
This house is only six years old.
Water hitting it is getting behind the faux stone, and behind the gutter and into the structure.
It has not made its way indoors yet, but it will!
What might a thermal camera see when the water begins coming inside?
It would likely see a little something very much like the image to the right.
Where was that image taken. On an older house, with a similar roof arrangement, in someone's house you all know. In the image you can clearly see the moisture, the studs and roof rafters, and drywall tape coming loose, literally falling down.
This problem would have been mostly, if not entirely, avoided IF the valley did not rush the water into the house, the gutter was larger and there was kick-out flashing at the edge of the house to divert water away from the faux stone and into the gutter.
There you go, to the right is another view of that leaky spot above, but with the Christmas Season color palette selected!
My recommendation: sometimes problems on a house are set up in advance by architectural design or the translation of that design into a 3D structure by the builder on site. No matter what, when that happens, other measures, different measures, have to be employed to resolve the issue. In this case my suggestion above of a wider gutter and kick-out flashing would help. Those things, however, will not solve the problem created by the many gallons of rushing rain water smashing into the house.
Jay Markanich Real Estate Inspections, LLC
Based in Bristow, serving all of Northern Virginia.
Office (703) 330-6388 Cell (703) 585-7560