Adding Exterior Window Trim Over Siding

Set the depth just deep enough to score the sheathing and the siding will come right off.

Adding exterior window trim over siding.

We used pressure treated 2 x 4 s for the trim around the windows and the doorway and then we had to create trim corners for both the inside and the outside corners like the ones in the picture above. Snap lines on the siding where you want to cut say 2 2 1 2 from the window and use a plywood blade backwards in a circ saw. If you just use 1 by stock 3 4 inch thick and rabbet the back inside edge to go over the flange the edge thickness won t completely cover up most lapped siding such as side wall shingles that are 3 4 inch where the layers overlap. The trick to installing exterior flat stock trim around a flanged window is having the trim sit flat in plane with the wall while the trim s outer face is proud of the siding for aesthetic reasons.

There is no need to remove all of the siding to install the trim. If we installed the trim after the siding we would have had to caulk a ton to fill in for the different levels the layered siding creates. Black is also a great anchoring color for exteriors featuring natural stone in various shades of gray. Most window trims are made from cedar or other types of wood.

Selecting the right window trim. Exterior window trim on vinyl siding if your home has vinyl siding and you d like to add vinyl window trim you will first need to remove the existing siding and j channel from around the windows. Window trim is necessary to every exterior. Black exterior window trim can be made from wood metal fiberglass vinyl or other materials.

I did this on a window replacement last year.