Replacing rotting window trims

Old 07-20-08, 09:31 AM
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Replacing rotting window trims

Original window trims are rough sewn cedar (2x4). Sidings are T1-11 for upper wall and stucko for lower wall on my 2-story house. The trims are half raised (half buried) from siding.

I replaced some rotting trims with pressure treated 2x6 (cut to size) in the past. My bad . Pressure treated lumber constantly twists, rips caulk, and requires more frequent maintenance than cedar. Now I want to replace all trims with composite wood. Ideal replacement would be 2x4, but local Lowes carries only 1x6. Here is my plan.

1) Remove trim and fill the space with exterior plywwod cut to size. This will make the surface flush with siding. If I find the right thickness marine plywood, I will use it.
2) Seal the gap between plywood and siding with siliconized latex. Paint over. Now the whole thing is rain worthy.
3) Nail 1x6 composite decking to plywood. Purely decorative.

My goal is least maintenance. Will I achieve it?

PS: My concern is if the plywood will also twist and rip caulking. Keeping the joint leak proof is the key.

PS: I live in Florida.

Last edited by puter; 07-20-08 at 10:28 AM.
Old 07-20-08, 10:56 AM
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Fill the space with a slice of T1-11. That way one sheet will probably do the whole house, and it will be the same size as the original siding.
Make sure your sealant is paintable.
Composite decking isn't 1x6. It is 5/4 x 6 with radiused edges, is that what you want? If not, you may can trim the radii off and wind up with a 3 1/2" board. You will have to screw the decking to your house, so make sure the backer will be substantial enough. Hopefully there is OSB or something behind your siding.
Old 07-21-08, 09:50 AM
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Thank you. I don't think there is any paneling behind the wall. Furring stip is the only nailing point for the wood siding.

Regarding the trim piece, there is window frame that I can screw t1-11, and I can screw composite trim to t1-11. I hope I got the picture right.

By the way, I have a different question and I would like to post a photo. How can I do that? Thanks.
Old 07-21-08, 06:29 PM
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I don't exactly know how .. but most post pics thru a free site like

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