Need advice on Window Jamb Extensions

Old 03-13-22, 06:56 PM
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Need advice on Window Jamb Extensions

We had a 4 season sunroom built but to keep the cost down to what we could afford, we are doing the interior finishing jobs. I've gotten most of it done or at least have a plan for it. However, I'm a bit confused on the best approach for the window jamb extensions.

The depth is about 4 and 3/4 inches, the windows are all 60" tall and range from 48 inches wide to 96" wide. I've got the concept of you build a box slightly smaller than the window and use it to fill the space between the window and the edge of the wall, but I'm a bit stuck on what wood to use. Our house is done in golden oak (yes I know it's dated but I'm fine with it and I'd like it to match the rest of the house). I've seen some prefinished wood at the local hardwood store and it runs $40 per 8 foot length. The unfinished oak is only $5.00 a board cheaper so hardly seem worth the effort of staining it myself. I get that lumber is expensive right now but does this seem in line or is there a cheaper/different product I should be looking at?
Old 03-13-22, 07:14 PM
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You can get oak plywood, it will probably run you $80 a sheet. But if you have a table saw you would get... 48 divided by 4.5 or 5.... so about 9 or 10 rips 8 feet long from it. (So $10 each) Then you would need to band the edges of the plywood, with either an iron on veneer or glue on oak screen moulding, or a thin rip of solid oak onto just the edge that you will see. (The edge the casing gets nailed to.) That will add a little more cost to it.

Everything is expensive, more so now than ever, so hope you can afford it.

Then you could also cheat a little. One thing I have done before is cut narrower rips... such as 3 1/2". Then nail on 1 1/4" of cheap wood, or even mdf. Shoot your jamb together. The cheap wood or mdf goes next to the window. Then I cover that up with an oak door stop moulding on all 4 sides. It's actually nice to do it that way if there are any tapers... the door stop goes right next to the window and covers any gaps. And looks a little fancier.

Base shoe also looks good but is smaller. But you might get an extra rip or two out of the plywood.
cjzimmer2 voted this post useful.

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