Calking on the aluminum capping on the exterior windows

When you put aluminum capping on the exterior windows on the outside side, do you put caulking on the open side. This is the side away from the window. I have heard one guy say you should not because you want moisture to go out. Can you please advice?

Generally no but it depends on the application. What type of house do you have (brick, siding, hardieplank)?

Brick

It does depend on the application, although caulk should ideally be little more than "cya" and aesthetics for water penetration. Proper flashing detail(including the wrap) along with low expansion foam should have the opening completely sealed and managing water properly. Caulking in a place that should not be caulked CAN cause problems.

you don't caulk brick to allow the moisture to escape and plus it would look horrible.

If you don't caulk the capping to the brick and mortar you will have gaps everywhere since not all brick work runs perfectly in a vertical line. Bugs and all kinds of critters will find this attractive to build their nest and condos. Since we don't have actual pictures of your project and statement like "you don't caulk brick and it looks terrible" is ridiculous. When caulking brick most guys will go with something like OSI quad for white or colors since it's a heavier sealant than silicone and tends to be applied in a nicer bead that wouldn't require tooling. Silicone is this application (size bead) especially if it's white or clear will get pretty dirty. For clear I recommend Geocel which stays very clean for a clear hybrid exterior sealant. Regardless, a good looking cap job and install can be wrecked by a bad caulk job!

Well said.

+1

Bad caulking is bad caulking but brick should be capped. It is not a water management issue as much as it is a petulance issue.

Don't me wrong, you don't want bulk moisture movement through there, however, the current construction methodology (i.e. brick veneer) does have a drying plane behind it.

It should be attractively and well sealed. IMHO

How are you feeling?