Sometimes a roof leak can be caused by the architectural design.
It rains, and often it rains hard.
Roof water has to not only move easily away from the house, but be diverted into gutters that are sufficiently sized to handle it.
In this case we have living space roof draining onto the steep garage roof, and into a valley which diverts the water toward the siding.
From there it moves into a valley which drains into a thin, 6' long gutter.
A gallon of water is represented by 11"x21"x1".
During heavy rains hundreds of gallons of water are diverted not only against the house, but then into a small gutter.
Water goes where it is directed to go.
The water from the upper roof meets the steeper lower roof and gains speed. More water during the rain increases the volume which gains more speed. Volume and angle cause water to increase in speed.
When I see this roof design, often the speed of the water forces it in.
The client arrived, and this was the first thing we talked about. I predicted what we might find inside.
In this case the only place it was coming in is in the garage. But I was right. It had rained the night before, hard, and this spot and areas nearby measured 100% moisture.
I enhanced the photo a bit to make the stain stand out. Inside the garage, unless you are looking, the stain is hard to see. The seller may not have even known it is there.
And my thermal camera, Mighty Mo, saw that the water intrusion was larger than the stain that was manifesting. Stains are not necessarily indicative of the entirety of a leak.
And this leaking had been happening for some time.
Fortunately it was only in the garage and it had not yet migrated into the house - a bedroom upstairs and an office downstairs.
What do I do? Observe and report.
What does the client do? Ask to have it investigated professionally and repaired.
What does the seller do? Decide whether or not to address it.
And the deal proceeds from there. The home inspector did his job - his client is informed. And everyone is aware of what is going on.
My recommendation: rely on the experience of your home inspector! Very often whatever you are looking at, like this roof design, the inspector has seen before! Hence the prediction in this case. Even if there had not been leaking, this roof design will always be there and the potential for the condition is there, unless there is flashing put in place to prevent it.
Jay Markanich Real Estate Inspections, LLC
Based in Bristow, serving all of Northern Virginia.
Office (703) 330-6388 Cell (703) 585-7560