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Living room window sill and trim question

marklevinson1's Avatar

Join Date: Mar 2006
Posts: 28

03-13-12, 08:49 AM   #1  
Living room window sill and trim question


I have installed all new windows in my house and have also done the interior trim for them with no issues. They are double hung Andersens with a rabbet and dado type setup for the window to receive the sill. You can see that in the first picture here, the rest are of the living room window:


I am about to do my living room window which consists of a center picture unit and 2 flanking casements. In the picture you can see I have put the jambs in place without nailing/screwing them to see what I am dealing with first. I am not sure how the sill fits into this scenario. Would the bottom jambs be replaced with a sill instead? Or would the sill go underneath the jamb? Or something else entirely. Obviously I have not worked with extension jambs before so any advice would be appreciated.



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chandler's Avatar
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03-13-12, 03:39 PM   #2  
Picture windows quite often don't incorporate a sill per se, as they are sometimes, not always, cased completely around. It is a personal choice, however. If you wanted a sill, it would take the place of the bottom jamb extension and extend with "ears" at least 3" or so on either side to accept the downward molding on the sides. XSleeper will be along shortly to give his take on this, so hang in there.

marksr's Avatar
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03-13-12, 03:45 PM   #3  
If I'm seeing the pics correctly, if you didn't install a sill, you'd need to add some drywall to cover the bottom edge...... but maybe that would be easier than incorporating a sill.

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XSleeper's Avatar
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03-13-12, 05:47 PM   #4  
Well, you guys pretty much covered it...

You don't necessarily "need" a sill (stool) since you can picture frame those extension jambs as-is if you miter every corner. But if you like the look of the sill and apron, like you have pictured in that first illustration, and want the same look on these windows, I would suggest that you use your extension jambs (attach them permanently) and then just add a 1" wide nose onto the front of the extension jamb.

When I have done that, I like to glue and nail some additional material onto the BOTTOM of the jamb extension (after it's installed) so that I have a little wider of a surface to glue/nail this stool nose to. I just rip some wood down to the right dimensions on a table saw- doesn't matter what, since it's all getting covered up... and glue and brad nail it onto the bottom of that bottom extension jamb. Then I'll take that 1" wide stool nose... glue it up... and affix it about 3/16" below the top edge of the extension jamb, nailing right through the front of the nose. The 3/16" "step" creates a little reveal there, to match the reveal that will be on the other 3 sides. The length of the stool nose should be about 1" longer than the outside dimension of the casing. The casing is also installed about 3/16" away from the inside perimeter of the jamb.

marklevinson1's Avatar

Join Date: Mar 2006
Posts: 28

03-14-12, 06:30 AM   #5  
Excellent! Thank you so much.

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