Thread: Caulking proud window trim on Mansard roof

I had a new roof (architectural asphalt) put on my 1967 Mansard styled house last year. Today, I am sanding, priming, and painting a window on one of the steep sides of the roof. This window (sometimes called eyebrow windows) is proud of the roof plane. I have added caulk to all of the wood joints of the frame and trim. My question: Is it good practice to add caulk where the painted wood of the window frame meets the roof tile?

I can see a trace of aluminum flashing in certain spots around the window framing, but it appears that most of the 1/2" gaps between the tile and wood have roof felt behind them. This particular window is subject to severe ice-damming. So I am concerned about moisture making its way behind the 1x wood used to build the frame.

I am now wondering is it proper practice to caulk (say silicone for its flexibility) around windows that sit proud on a mansard roof?

Thank you,
Michael

Similar Threads:

• Single Wall Window Installation
• Window seal problems! Help!
• Window safety locks
• Window in combo bath/shower area
• Leaking window

Originally Posted by Michael Civisca

I had a new roof (architectural asphalt) put on my 1967 Mansard styled house last year. Today, I am sanding, priming, and painting a window on one of the steep sides of the roof. This window (sometimes called eyebrow windows) is proud of the roof plane. I have added caulk to all of the wood joints of the frame and trim. My question: Is it good practice to add caulk where the painted wood of the window frame meets the roof tile?
I can see a trace of aluminum flashing in certain spots around the window framing, but it appears that most of the 1/2" gaps between the tile and wood have roof felt behind them. This particular window is subject to severe ice-damming. So I am concerned about moisture making its way behind the 1x wood used to build the frame.
I am now wondering is it proper practice to caulk (say silicone for its flexibility) around windows that sit proud on a mansard roof?
Thank you,
Michael

Hi Michael,

Difficult to say without a photo. Also, I am not in a cold climate, and things may be a bit different there, but I will do my best. Maybe someone from your climate will chime in too.

Caulking is typically a good idea, particularly in exposed areas and wherever you want to keep water out. The one place that I would suggest avoiding caulking is at the bottom edge of the window trim (under the sill, for instance). That way, if water gets in from above, it has a place to get out. This is not always the case (once again, a picture would help).

I am not a fan of silicone caulking for the exterior. I prefer one of the polyurethane caulkings. Good products, stay flexible for years and can be painted. Pretty stinky and difficult to work with. Wear gloves. As a matter of fact, wear old clothes because the stuff gets everywhere.

Thank you Gunnar:
I did, in fact, leave the bottom edge open for drainage. I decided to go ahead and caulk the to side edges of the exterior frame with silicone. I never worked with the poly caulk, but I will try it on some other areas.

I did get in touch with a few roofing/siding companies after posting my question. Interestingly enough, I found one company that caulks with silicone between the j-channel and window frames after installing vinyl siding. Their theory is to keep moisture from getting behind the cladding and causing issues if for instance the house wrap underneath is not sealed correctly.

I do like silicone (usually colored) for exterior because, it too, remains flexible through the cold periods here in Western New York. I know painters don't like it due to the inability to paint it. Although there is now a silicone/acrylic blend caulk which is flexible and paintable.

I am interested to see what other inspectors have to say about the Mansard/Window issue.

Pictures?

Here is the type of window that is on my house. After researching a bit on the internet, it was incorrect to call it an eyebrow window in my original string.

So, where the window frame meets the roof tile is the area in question. On my house, roof tile cover the top part of the window