Simply put, a flawed gutter design can damage the house.
Remember the axiom -
WATER IS THE KILLER OF HOUSES.
It is self evident. It is true. It is and it will always be. And inside and out.
Notice the arrows.
Problem 1 has a red arrow.
Problem 2 has yellow arrows.
Dealing with Problem 1 first, it looks like the whole roof is sinking to the left.
What can't be seen from this photo is the siding on the left is rotting above and below the roof.
The roof decking is rotting.
See the two downspouts above the red arrow?
Together they discharge 100% of the roof's rain water onto that small front roof, and therefore to that small front lower gutter.
OF COURSE THAT'S TOO MUCH WATER FOR THAT LITTLE ROOF AND LITTLE GUTTER! IT IS NOT A WIDE GUTTER!
A gallon of water is contained in a roof surface area of 21" x 11" x 1". It is what it is! So, during a heavy rain, a raging flood is happening onto that small front roof.
During a 1" rain storm, that would mean 348 gallons of water would drain toward that small front gutter. It is not designed for that much water in such a small amount of time.
Someone tried to help this situation by putting another small piece of flashing at the corner under the left downspout. Too little, too late.
And the cracked, rotting siding was also repaired, with a drywall screw!
It seems to me that drywall is the only thing that drywall screws are never used for!
So we have a damaged roof, damaged siding, and obviously a damaged structure and the front porch roof is sinking.
THE FRONT PORCH ROOF DID NOT HAVE A CHANCE!
Problem 2 is interesting as well.
The sidewalk has settled dramatically, erratically, along with the front stair. Many trip hazards have developed. But why?
Look at the yellow arrows. They point to the buried discharge locations for two downspouts!
Over the small front roof that downspout is from the neighbor's house. It discharges in the front yard right beside the subject house downspout, beside the front sidewalk.
The homeowners solution? Pack a couple wheelbarrow full loads of Virginia clay soil to fill the huge holes which no doubt used to exist there!
So we have 100% of the water from the subject house roof, along with 2/3 the water from the house next door, draining beside the front sidewalk.
THE SIDEWALK DID NOT HAVE A CHANCE!
So, both the house and the sidewalk are being slowly killed every time it rains.
My recommendation: builders simply have to be smart about gutter and downspout placement and discharge. Every time I see what will eventually be an overwhelming gutter situation on new construction I bring it up pre-drywall. While utterly common sense, my comments are NEVER appreciated by builders. Yet they will agree to alter it. The physics and fluid dynamics of gutter water are not hard to understand. The math is hard, the concept is easy. Too much is too much. And in some contexts the larger, wider gutters and downspouts are necessary. The larger materials should be considered more often than they are.
Jay Markanich Real Estate Inspections, LLC
Based in Bristow, serving all of Northern Virginia.
Office (703) 330-6388 Cell (703) 585-7560