Exterior window trim advice?

4 years ago

My 1990s ranch home has vinyl windows without trim on the exterior. I’d like to add trim, similar to what this picture shows. It looks to me like this trim was added on TOP of the lapped siding rather than the siding being cut away first. (The trim in the pic is PVC.)

Is this a bad idea? The back (south side) of my house has flat wall boards that look like fake bead board, but the front (north side) has lapped siding. I live in rainy SW Washington state, where we get 40 inches of rain a year!

Obviously I would caulk the cap, but it would be tricky to thoroughly caulk the side edges.

Thanks for any advice you can offer.

Featured Answer

PRO

PPF.

4 years ago

I'd want flashing above the head trim.

https://hammerandhand.com/best-practices/manual/1-flashing/1-2-head-flashing/

Comments (10)

nanitamalia
Original Author
4 years ago
Yes, I agree. What do you think about the sides?
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PRO
Windows on Washington Ltd
4 years ago
Sides are normally just a caulk joint. If you are feeling very industrious, you could rip the trim in a manner to close the gap slightly, but it would be a caulk joint.

The other option here is the cut the siding back in these locations and apply the trim straight to the sheathing wall (if there is any).

How about some pictures and more details about if there is any sheathing and what the rest of the make up is. You are adding a big "speed bump" to a wall that hasn't leaked before and may be introducing some issues in a very wet climate.
nanitamalia
Original Author
4 years ago
Sample front window, with siding. Back window, with T-111 gen 2.
nanitamalia
Original Author
4 years ago
Windows on WA, thanks for your thoughts. I haven’t pulled up any wood to see the flashing (or lack of flashing), so I can’t give you more details other than what the pictures above show. You’re right that I may open a can of worms for a cosmetic improvement!
PRO
toddinmn
4 years ago
you could just butt it up to what looks like a J -channel built in to the window. I think you would be safe to do it without any caulking or head flashing. Putting in a head flashing would not really be that beneficial in this case and can be a real pain to get in correctly.
nanitamalia
Original Author
4 years ago
Thank you for your advice, everyone. @toddinmn, it’s very tempting. Now that I am looking at other people’s window frames, I have window frame envy!
PRO
toddinmn
4 years ago
The pic you showed is a pretty simple design. You could Could pre assemble 1 and just hang it there like a picture to see if like it.
Cheryl Smith
4 years ago
The home we bought a couple years ago is the same. It just looks so unfinished. I have been thinking of doing the same
HU-854057427
4 years ago
last modified: 4 years ago
There is also azek board for trim which is an weatherproof composite which can be cut to size and come is various widths x 8' x .75 inches thick and is less expensive than PVC sold at Home Depot. There is an online company "Architectural Depot.com" which I used to order colonial style brick mold for my front door. Their website is user friendly and interactive in that you pick your style and size you need and the calculator give you the exact price. The order form is online as well. The offer brick mold in wood and polyurethane.