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jasonc
Fixing Window Jamb Extensions

I just built a new home and am down to installing window casings. I have about 28 Anderson windows with factory installed jamb extensions. The extensions protrude beyond the drywall by as much as 1/4" at the top and taper down to 0" at the bottom. The taper is due to the use of window wraps on the exterior that are overlaid at the bottom thus making the wall thicker. I am having trouble installing the interior casings because of this taper and the jamb sticking out beyond the drywall. It is my understanding that ideally you want 1/16" to 1/8" of jamb beyond the drywall all around the window. I cannot remove the jamb extensions. How can I fix this problem in place? Thanks - Jason

KKelly
Re: Fixing Window Jamb Extensions

Andersen Extension Jambs are a Tongue and Groove wrap which is why we don't normally have them factory installed, the whole point is the extensions are adjustable. If they are not factory installed, we normally adjust them during installation to compensate for inconsistency. Your supplier probably didn't say, but Andersen gives you the choice and, regardless, they're very easy to remove or adjust.

This is a little difficult to explain without a picture but. Put a 3/4" straight cut bit on your router and set it flush with your router base plate and then set that flat on your window wall. The problem is, turn the router on and it cuts nothing. Now, raise up one side of your router plate by attaching a 1/2" piece of anything to one side of the bit and lower your router bit flush with that. Now, if you turn the router on, anything not flush with that 1/2" piece gets cut away. That's how we cut away extending window jambs or anything else.

I hope that makes sense.

JLMCDANIEL
Re: Fixing Window Jamb Extensions

Although the router is fast it is possible that you will do some serious damage also. For no more than what you need to remove, I would use a hand plane and plane the extension down to the proper level.
Jack

KKelly
Re: Fixing Window Jamb Extensions

I would like to use a hand plane too Jack but Andersen Jamb Extensions, as most factory applied jamb extensions, are stapled together. A hand planer could, unless under the best hand, pull them apart and make things worse. In my opinion, a router requires less skill than a hand planer.

jasonc
Re: Fixing Window Jamb Extensions

Thanks. I think I understand but just one question. Does the 1/2" piece then ride on the drywall? I agree this sounds pretty good, but I can also see where just one wiggle of the router could gouge into the jamb.

KKelly wrote:

Andersen Extension Jambs are a Tongue and Groove wrap which is why we don't normally have them factory installed, the whole point is the extensions are adjustable. If they are not factory installed, we normally adjust them during installation to compensate for inconsistency. Your supplier probably didn't say, but Andersen gives you the choice and, regardless, they're very easy to remove or adjust.

This is a little difficult to explain without a picture but. Put a 3/4" straight cut bit on your router and set it flush with your router base plate and then set that flat on your window wall. The problem is, turn the router on and it cuts nothing. Now, raise up one side of your router plate by attaching a 1/2" piece of anything to one side of the bit and lower your router bit flush with that. Now, if you turn the router on, anything not flush with that 1/2" piece gets cut away. That's how we cut away extending window jambs or anything else.

I hope that makes sense.

bsum1
Re: Fixing Window Jamb Extensions

How about using a belt sander?

bsum1
Re: Fixing Window Jamb Extensions

Yes sir,like using the router using caution. The sander might be a little easier to balance than the router.

brettmarl
Re: Fixing Window Jamb Extensions

i'd love some clarification on this thread, as i'm confused about one part. i'm a bit of a noob, so bear with me :)

if the jam extensions stick out past the drywall in a 'tapered' way (ie. lets say 3/8" at the top, and 0" at the bottom), then won't planing them flush to the drywall cause the reveal of the extensions to look bad when finished? ie. it won't be even, and will also taper - and might be quite noticeable.

would a better option to be build up the wall with mud to bring the un-planed jams flush, feathering it out a long way to ensure it isn't visible to the eye.

llobeck
Re: Fixing Window Jamb Extensions

I have a similar problem - we removed paneling in our living room as part of our updating - it seems previous owners planned the windows around this paneling. We're ready to trim but realized the window casings extend out at least 1/4" past the drywall. How do we trim the windows and make it look flush?:confused:

JLMCDANIEL
Re: Fixing Window Jamb Extensions
llobeck wrote:

I have a similar problem - we removed paneling in our living room as part of our updating - it seems previous owners planned the windows around this paneling. We're ready to trim but realized the window casings extend out at least 1/4" past the drywall. How do we trim the windows and make it look flush?:confused:

1] you can rabbit out the trim
2]you can use a belt sander to sand the jambs down
3] you can use a router and sled to cut the jambs down
Jack

Donnie_Baseball
Re: Fixing Window Jamb Extensions

I searched the forum and did not find quite what I need, but his thread was the closest, so here is my problem:

I just bought a new home last fall, and am finishing my basement (learning as I go). I now need to make and install window jam extensions for my vinyl (Anderson) windows. I have found several sources discribing how to prebuild a picture fram or box. While these discriptions mention that the depth from drywall to window should be even, mine are not, with up to a 1/4 innch variance from top to bottom, and there is not room to add an additional "shoe plate". I barely know how to run a table saw, moreless rip boards on an angle. Is there a simple (or not so simple) solution? [Or do I need to call my builder to fix (rehang) the windows?]

Thank you for your help and insight in advance.
~Donnie B

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