# How does one fill a large void in a window sill?

Hello. The windows in my Mom's house were just replaced. Apparently they had to move the windows about 1/4" forward from where the previous windows were (according to the person who installed it, this was necessary to get a good seal so air couldn't get it - apparently the previous windows had not been installed correctly and didn't have a good seal) so on each window there's now about 0.25" space on the window sill (between the sill and the window).
I asked the window person what to do about the void. He said to fill it with a piece of wood so I'm attempting to do that. The other alternative I guess is to use wood putty or bondo to fill in the void.
I measured the void on one window to see what size of wood I would need. Upon doing so, I found out the distance between the window and edge of the sill (the depth measurement) varies significantly as you go from one end of the window to the other so that one piece of wood with the same cross-sectional area would not fit well.
Solving this is a head scratcher for me. The space seems too big to fill it all with wood putty or bondo (the size of the void on each window is roughly 35" wide, 1" high, and 0.25" deep so it would be a lot of wood putty or bondo).
I'm guessing the thing to do is fill each void with several pieces of wood, each piece having a different depth (since the depth of the void changes as you go from one end of the window to the other) and glue them in somehow (or nail them in with small nails and top it off with wood putty) and then fill around those pieces of wood with wood putty or bondo. And somehow make all this look like a continuation of the existing window sill after the sill and void are painted.
I'd appreciate any ideas on how to solve this problem. I'd also appreciate responses from people who have used a lot of wood putty (or bondo or whatever) to fill a large void like what I have and how it worked out.
Thanks!
Steve
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Steve wrote:

If the window was moved forward horizontally why is there a gap vertically? ___________

Why didn't you tell him he left the void and he should fix it? ____________

Take a piece of wood 3/8" or so greater than the distance from sill to top of gap. Now cut a rabbet in it so that the tongue is just slightly less than the tallest part of the gap. Cut it to length, whatever width you want, make it pretty, put plenty of caulk on the tongue, bottom and rabbet and shove it into gap. Wipe off excess caulk (you want it to squeeze out).
--

dadiOH
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Bondo or putty is a hack job. Don't even think about it
You have a couple of choices. If I could see it in person or a photo I may have a better ideal, but here is a couple of suggestions. If I'm reading this right there is a gap between the sill and window not the sill edge toward the room.
Replace the sill entirely using a wider piece of wood. If you want to dress it up, use marble or Corian instead of wood.
Shape the wood to fit. This requires some tools, such as s aw to cut it as close to the dimension as possible, then use a plane to get the perfect fit. A small block plane is ideal for that sort of thing.
Another possibility is to fill the void with caulk to seal it, then put a thin piece of trim over it.
--
Ed
http://pages.cthome.net/edhome/

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on 10/6/2007 2:35 PM Steve said the following:

How about replacing the sills? If worse comes to worse, buy oak boards and make new sills yourself, or have a carpenter make them. How many are we talking about?
--

Bill
In Hamptonburgh, NY
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Steve wrote:

Your mother's windows were a wood common opening. The installer put the replacement windows against the outside stops, so they wouldn't have to cap off the exterior. In doing so, you see the results on the interior.
The installer should have trimmed out the interior with 1/4 round.
The other option was to install against the inside stops, and cap off the exterior with aluminum. This is the preferred method, especially if the inside woodwork is stained, and not painted.
It appears, your installer did not want to complete the job for a nice appearance. This is done often, by bidding a job low to get the installation. But, you get a half-assed job. Sometimes, it's just to cut corners, and put more profit into the job. Other times, some just don't know how to do the job right.
Check your contract, to see exactly what was included with the installation.
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Steve wrote:

What are the new windows made of? uPVC/ Aluminium! Seems to me that this was an unprofessional job, though I speak from the other side of The Pond, so contract conditions could be different. If the frames are timber, do you have enough space to put what we call quadrant beading between the cill and the window frame? I guess you should have.
HTH
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Two choices that I see:
Insert backer rod to control the depth of caulk and prevent 3 sided bond. Use a good grade of caulk. I would use polyurethane, NOT silicone. Use good painter's latex if you plan to paint.
Use some trim. Choices, at a real lumber yard: lattice, 1/4 round, base shoe, door stop. If the trim has a shape, it will need to be coped or mitered. Lattice trim could be square cut. This will need paint. There are prefinished non-wood trims that are quite easy to work and install.
--
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Keep the whole world singing . . . .
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I can't provide any ideas not already presented, but I would make one suggestion. Don't use that same contractor again and if anyone asks for a recommendation, let them know to avoid the hack you had.
--
Joseph Meehan

Dia \'s Muire duit
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If I understand your question correctly, I had the same problem when I replaced my windows. It doesn't mean that the old windows weren't installed correctly, it means that the new windows are "thinner" than the old ones, say 3.25 inches deep instead of 3.5. When the new windows are pushed back against the exterior stops, an interior gap is the result.
As Dan suggested - backer rod and caulk will solve the problem. See this site for info on backer rod:
http://tinyurl.com/2ghkrf
Don't try the borgs to purchase - none of my local home centers carried it nor did anyone in the paint/caulk department know what it was. I went to a contractor supply house and paid between .05 and .065 per foot depending on the thickness. The supply houses sell it in bulk by the foot as opposed to packaged in pre-cut lengths. It's much cheaper than way. I used 1/4" or 3/8" around all 4 sides of my windows before caulking the interior. There'e really no good way to caulk deep gaps without it...that's what it's made for.
My concern is that if the contractor did not seal the inside of the window along the sill, what else didn't he do? By sealing both the exterior and interior edges of the entire window, you create the desired dead air space.
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