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window trim for vinyl siding and other questions - carwashguy - 05-20-2020

Wild turkey posted a question last week inquiring about vinyl siding.  I need to reside my house and I'm going to use Harvey industries Premium non-insulated Vinyl but I need to make some choices about trimming out the window and doors.
First let me tell you about my wall assembly.  From the inside out there is 7/8" drywall (it may be some type of cement board and plaster), 2x4 wall with fiberglass insulation, 3/4" plank sheathing covered in tar paper, masonite pressboard clapboards covered in Aluminum siding.  
My intention is to remove the Aluminum, Masonite and tar paper but from there I'm not sure the best way to proceed.  I'd like to add 2" of foam board insulation and that adds a lot of things to be concerned about.  I need to add the correct house wrap,  apply the 2" foam board and trim out the windows to accommodate the added thickness created by the insulation.  i found this video which is great but I don't like the choice of window trim material https://www.youtube.com/watch?v=cOU83YWJ4Jg
Is it possible to trim the windows using PVC boards?   I think I read somewhere that the PVC trim makes a lot of noise because of expansion and contraction.  Does anyone know if this is accurate? Any recommendations for an alternative material


RE: window trim for vinyl siding and other questions - goaliedad - 05-20-2020

Trim the windows with 2 by 4’s or thicker as needed, wrap that with aluminum, put it the foam and siding


RE: window trim for vinyl siding and other questions - srv52761 - 05-21-2020

Check the siding manufacturer’s literature.  There is a limit to the depth of foam board you can use.  I went with 1” iso board.  Normally the reflective side goes toward the exterior.  With vinyl the reflective side goes towards the interior.  Fill any gaps around rough openings and corner studs with canned foam first. Tape all seams, of both the foam boards and the tyvek.


RE: window trim for vinyl siding and other questions - MstrCarpenter - 05-21-2020

I've wrapped many homes with foam insulation; including my own. The thickest I would do is 1". I put 3/4" Dow on my ranch when I ripped the roof off and changed it to basically a cape w/ dormers. I chose 3/4" to be flush with my window/door casing. (The sills were extended and wrapped with alum. up to the stool cap.) With wrapped sills, and a substantial head casing I can just use vinyl siding window casing that negates the need for lots of ugly "J" channel. My opinion is that it's the air tight envelope with no thermal bridging rather than the thickness (R-value) is what makes this improvement so valuable. Recently there was a thread about insulated vinyl siding. There's no real R-value in it because you haven't really slowed an air flow.


RE: window trim for vinyl siding and other questions - tomsteve - 05-22-2020

(05-20-2020, 09:05 PM)goaliedad Wrote: Trim the windows with 2 by 4’s or thicker as needed, wrap that with aluminum, put it the foam and siding

i like the look of this and prefer aluminum wrapped window trim. no maintenance. if ya go this route, break/bend the top piece so it runs up the wall a bit.


RE: window trim for vinyl siding and other questions - Turner52 - 05-22-2020

As tom steve said. Let it run up the wall on the top piece minimum. Works as flashing. When I did it on my last house I did it on all 4 sides. It was an old farmhouse and the wide window trim installed on new windows gave the old look we wanted. Did the same on the corners. Did not want the vinyl siding outside corners.