On new construction I see a lot of dormers on roofs that are simply interesting architectural details and have no function other than to look good.
Dormers as architectural details CAN look good, but can rot quickly.
I say that for lots of reasons.
There is usually a lot of wood.
Of course, wood has six sides! All sides MUST be primed and the exposed faces painted with two coats ON TOP OF the primed coat.
They say to never say never. In my experience (that is my disclaimer) builders NEVER prime all six sides. During an inspection I can see from the brush strokes that the contractor did NOT use two coats.
And worst of all, OFTEN the painting is done when it is too cold outside, which sets the paint up for failure.
I have had many posts about painting DONT'S, but HERE is one about when it's too cold to paint.
The paint peels and the wood rots.
OFTEN the joints are not mitered well, with wide gaps and very unprofessionally. Of course, the gaps are filled with caulking. Caulking does not last very long. Gaps open up and the wood rots.
But here is one important point.
Do you see the raised shingles at the top? Those are the so-called ridge vents.
They are a slice out of the roof through which air travels to help ventilate the space. Such venting is essential.
It helps carry off heat and moisture.
From the inside these dormers are open to the general attic space. You can see the big opening cut there. And intentionally! This is so air will flow. Convection moves the air from the soffits to the ridge vents. Heat and moisture is carried off as this air moves.
But looking inside those dormers from inside the house, I can clearly see the bottoms of shingles!
Number one, the vent is pretty narrow. It should be about 4".
But number two, the cute vent might be visible from the outside, but air cannot escape if the slot is covered by shingles!
CLEARLY THIS IS A ROOFER, OR HELPER, WHO DOES NOT UNDERSTAND WHAT HE IS DOING.
If heat builds up and air does not move, the space becomes more conducive to the amplification of molds and rot. Dead air is friendly to mold and rot!
I looked out the window and from this room saw four other houses with the dormer detail.
Typically, in my experience (there's that disclaimer again), when a mistake is made in one place the same contractor will make it over and over! I will never know, but I would LOVE to see under those other dormers on those other houses!
In time, as these dormers begin to rot, people will chalk it up to wood doing what wood does. Sure, the installation is crucial, but so are the physics! These dormers are set up for failure, just like the paint job.
My recommendation: a pre-drywall inspection looks at everything. Houses are composed of systems which all interact to make it healthy and properly built, or the opposite. Pre-drywall is one great way to see how those systems interact.
Jay Markanich Real Estate Inspections, LLC
Based in Bristow, serving all of Northern Virginia.
Office (703) 330-6388 Cell (703) 585-7560