Caulking them is a mistake and the caulking is likely to fail prematurely.
Caulking j channel around windows.
In a hard rain you better believe rain will get in that seam.
If they need if it needed to be caulked they would have done that.
One of the things to keep in mind especially with newer construction is the lack of roof eave overhang.
Caulking can be placed behind the j channel during installation sealing the seam between the j channel and the house wrap also sealing the seam between the j channel and the window itself.
There are window wrap products that are made specifically for wrapping a window or door to stop water from entering the opening.
But if done incorrectly it can lend a sloppy amateurish look.
You can use some painters caulkon the inside where the window meets the casing or the drywall.
And you generally don t have to caulk between the back of the j channel and the side of the window.
If it was installed correctly there shouldn t be a draft coming from this area.
Caulking on the interior is mainly for aesthetics.
Caulking the j channel to the window or door can actually create a dam and allow water into a wall cavity instead of allowing it to travel down the exterior and away from the opening.
They re not like large pieces of siding which may have substantial expansion contraction.
Many vinyl siding installers do not realize the importance of the house wrap and its job as the sole water barrier because many people incorrectly believe that vinyl siding keeps the water out.
While paint does tend to somewhat glue these pieces together caulking them is never advised and can cause permanent damage.
Caulking windows to give them a finished look inside and out and seal out leaks and drafts is a fairly common diy task.
Researching the proper steps for installing j channel.
Installing j channel around windows can be a difficult part of the installation process.
Bottom of siding boards should not be caulked water is meant to exit through the bottom of each board.
On the other hand if the j channel isn t caulked to the wood or vinyl window frame i call it out as an incomplete installation.