Extending Window Jams

[DIY_Rick]

Hi,

I just recently installed drywall for a neighbor in his basement, he has now asked me to extend the jams so that they meet the edge of the drywall. The problem is, the jams need to be extended about 6.5 inches. The window openings in the new walls constructed in the basment (2 X 4 walls about 1/2 inch from the cinder block walls) are already framed out. He has left about an inch on each side of the 2X4 for jam extensions and shimming. he would like the Jam extensions to be wood so that he can stain them.

What is the best way to accomplsh this? My first thoughts are biscuit joins using the existing jams and 1 X 8 board ripped to size. Someone else suggest pocket screws but then we would have to remove the drywall and framing to get the tools in there. Dowels - similar to biscuits I guess.

Any help would be greatly appreciated! If you need more info, I might be able to get a close-up picture of the windows.

[Rich]

Images are always handy to see actual conditions :)
I'm not sure if I would hard connect to the existing window jamb. Would be better to dado the jamb extension behind the existing window to allow for expansion / contraction.

[DIY_Rick]

Thanks Rich.

Here is a photo of the window setup. It would be difficult for me to get any tools on the back side of the jamb on the window itself. The piece I am attaching, which will be 1 X 6, I can do almost anything with.

Again any help would be greatly appreciated.

Thanks,

Rick

[Rich]

IC Rick.
I think the best would be to butt it into the frame. One problem with that is there isn't much to bear the weight of the extension jamb right next to the window - so you'll probably have to put some backing in there.

[TnAndy]

I'm curious......how do you view the photo.....all I see is a box with the Jpeg title and some info about the photo.

Anyhow, on the jambs.....

I build a "box" on extension jambs of any depth more than an 1" or so....that is, nail all four pcs together before putting it up to the window......that way it helps support itself. Then attach to the side walls and shim where accessible.

[Dragon]

That is the way I would do it as well.

[mfinley919]

I would tear out the existing jams and replace with all new. Eliminates all the issues of butting new to old, eliminates the much bigger issue of the new and old jams not matching each other once stained.