Originally Posted by supermike
I just finished siding my new 2500sqft shop with dutch lap and found there is no need for utility trim under windows or soffit. Where you cut the siding for the last course determinds how the siding sits in the j mold and if ripped plywood shims are required to be nailed behind the cut top edge of siding. This will keep the siding pushed out far enough so that the punched out tabs stay engaged into the inside lip of the j mold. All it requires is carefull measuring so the last course piece is not to big or to small so the tabs engage properly.
That sounds like a good idea except it won't work on windows that have a built it 'J' because there is no curled under lip in the windows 'J' like there is in regular 'J' trim for the punched tabs to latch on to.
That said, however, I'm wondering if maybe no utility trim would even be necessary under windows whether the windows had built in 'J' or if you used 'J' trim under windows that didn't have it.
What I mean is, why wouldn't the portion of that course under the window just stay in the 'J' ?
The bottom of that course is latched onto the preceding course plus the portion under the window is still connected to the full height of the course on either side of the window.
I think it would be too stiff to just droop down even if it weren't latched onto the preceding course.
It might be necessary, however, to pad out with plywood or whatever to keep the cut edge from bowing in from its normal Dutch style projection.
I think I'll do a test on some scrap pieces to see how that works out.