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
Hi Jay,
What crappy work on the venting. Was there no ridge venting installed at the ridge? I don't see any. Ridge cut too small like you said it needs 2 inches on each side of the ridge. Not Two inches total.
Many builders want to show off their work. But after we get there they don't want us back. They have nothing to be proud of. Until shown how to do it right the first time. They will continue to do it the wrong way till caught by a inspector.
Have a good day in Bristow my friend.
Best, Clint McKie
Yes, Clint, I said it should be about 4" wide total. But even if it is wide enough, if covered by shingles and air can't move the width is immaterial.
Good morning professor; my lesson for today is "Dead air is friendly to mold and rot!" Thank you for the lesson.
I have to agree. Dormers are nothing but a hole in the roof that lets water in. Great post! Congrats on the feature!
'Tis Ken, especially in below ground living spaces or crawl spaces.
I understand the reason - making houses all look different - but given the choice, Michael, I would choose one without dormers.
After 25 years and no big issues, now I have to go up and peek at the underside of my dormers
Ed - well done they should last a long time!
Jay, Who'd have thought dormers could be so potentially complicated? Good to know!
Unprofessionally done, Bliz, they are opportunities for weather to destroy!
Mistake, stupidity, or laziness? Hmmm, maybe all three? Dormers are a nice architectural design, more so if they go into a room upstairs, or open a ceiling area. If they are just "dummy's" for looks, it makes no sense to me.
It is a dummy detail Fred. But for looks only. As these mistakes are amateur ones, due to the "professionalism" in new construction that I so often complain about.
Jay, something as simple as a decorative piece can cause long term problems. Another good reason for a pre-drywall inspection. Catch these things before a problem occurs.
Good morning "Father of Pre-Vention".....akin to Mother of IN vention....good point....decor can be a chore !
I have to agree that a pre drywall inspection is a must to ensure all items are correct. It is expensive when they have to go into the wall.
Hi Jay.... capes with a gable roof lack light and space upstairs.... gambrel capes have the floor space and then the gable dormers are not needed....
That's the idea Mike! We try to catch, too!
Very good word S&D! I like it!
Harry - despite the builders continually saying that with so many inspections by the supervisor and county that a home inspector isn't necessary?
Barbara - I like a gambrel roof detail, but you're right about them not needing dormers.
Too late, I have three dormers that look to be done properly. Thank goodness.
ANother great post with lots of helpful information. I never really thought about the fact that fake dormers are more of a liability.
Never would have thought that fake dormers could cause so many issues.
Jay -- if they are going to put dormers on for decorative purposes - one would think they would take the extra care to make sure they weren't just creating future huge holes in the roof.
And I am happy for you Tammie!
They are a liability in that they are more vulnerable to weather than no dormers Marc.
Frank - even real dormers can cause those issues!
Steven - that's essentially what they are. Look at the gap on the wood trim just under the shingles, yet to be painted. That kind of gap is typical. They will fill it with caulking. Not good!
Jay - I almost never see all sides of wood painted. Its a forgotten area, out of sight out of mind.
Morning Jay wasn't aware of the painting of all sides of the wood. I learn something new everyday here on the Rain.
I agree Eric. Bare wood is bare wood, no matter where it is. And one the end, bare wood is a zillion straws.
James - see the response to Eric! But think about it - wood has six sides.