The brickmoulding can also be used with siding; the name refers to any relatively narrow and deep moulding with a stepped profile.

Your aluminum-clad window has a nail-fin that is slid into a groove on all 4 sides of the frame. That fin lies flat against the sheathing of the house (usually but not always over the weather/air barrier) and gets nailed in place. Then self-adhering flexible flashing is applied over the nailing fin (preferably covering the frame to fin joint because it is prone to leaking).

Then casing trim is added over the flashing on the top and sides (but not the bottom because that detail tends to leak). The trim can be 3/4" or 1" thick depending on the thickness of the wall cladding. It can be wood or PVC. It can have a backband molding at the outer edge and/or a crown molding at the head. It could be flat 3 1/2" or 4 1/2" wide or brickmoulding. The choice depends largely on the design of the house and your budget.

The company also makes the extruded aluminum "brickmoulding" that you mentioned. It snaps into the window frame in place of the normal nailing fin installation. Then the nailing fin is attached to the outer edge of the brickmoulding. The brickmoulding and the fin both lie flat against the sheathing and the flashing is installed as described above and then the exterior wall cladding is added.

Check out the detail on their website under trim options.

Here is a link that might be useful: aluminum brickmoulding option

IÂm very confused by this as well. Macv  IÂm afraid you talk over my head - I obviously have a lot to learn.

I clipped this picture from a previous thread. Brutuses wrote: "We used treated wood with our hardi plank siding".

This is what I would like to do (along with a sill and apron) but donÂt know how. Was the top (more intricate) part of the trim laid on top of the siding? I would think trying to cut siding to butt up to that part of the trim would be very difficult if not.

The photo appears to be of conventional window trim with a crown molding at the head although the fiber-cement siding may have been furred out from the sheathing with strapping.

The siding always butts into the trim. It is not difficult to scribe the siding to the trim profile using common tools any finish carpenter would have. Some things require more skill and experience than others.

Here is a link that might be useful: PVC window trim

So macy, you are saying that the aluminum brickmoulding would be done in place of the other, casement moulding? Or would I need to do some extra, casement moulding? I was thinking about just doing that, but I figure that the matching clad moulding is there with no problem, so I may as well use it.

Also, as I understand it, the clad brickmould only goes for the top and the sides, and not along the bottom. I suppose that I would need to put some type of moulding there as well. I would prefer that the clad be all around, though.

Another question - when I would go to paint the siding, would I have to worry about not being able to clean the aluminum?

You can use the aluminum brick molding alone or with additional trim or use flat casing trim in place of it. If maintenance is a concern you can use PVC instead of wood trim. You should also compare costs if there are a lot of windows.

I don't know how the sill is treated in this window but the brick molding should most certainly NOT be placed under the sill. The only way I know to make a window look reasonable and not leak is to add a sill nosing that extends left and right under the jamb trim and projects outward over the siding. ATW make two different sizes of PVC sill nosings.

I don't understand the issue with cleaning the aluminum.

WeÂre in S California. It doesnÂt look like ATW sells here. Do you know of a window trim manufacturer that does?

ATW just makes it easier; you can always make the pieces out of cellular PVC as shown in the link.

Here is a link that might be useful: PVC window trim