Doors and Windows - installing replacement window: from inside or outside?

Hey all. I want to replace an old (50 year old) doulbe hung wood window with a vinyl sliding window. I checked for dimensions.

Now how to install it!? Some people tell me I have to remove the outer trim and maybe even have to break some of the stucco in order to install it from the outside, nail the window's flange to the casing, and then patch the stucco and seal. That sounds like a lot of work, because of the stucco mainly.

Some other people tell me I should just cut off the flange, and install it from the inside, driving nails from the inside of the window into the casing (so that the nails will be parallele to the plan of the window). That sounds much easier (no worrying about the stucco).

So which way do you recommend? Thanks!

Since you are dealing with a stucco exterior, install it from the inside. Don't use nails to secure it to the existing jamb -- use 3" deck screws. Make sure to place them so they don't interfere with the windows operatiion. And, assuming that the new window is vinyl, leave the heads of the screws out an 1/8" or so from the frame of the new window.

Thank you so much for the quick answer. I'm going to replace the window this afternoon. One thing confuses me: I guess the deck screws I'll buy will have flat heads, right? The replacement windows are 100% vinyl. Why should I leave the screws out 1/8''? Why not screw them so they are flush with the interior frame of the window? Are you afraid they'll split the vinyl?

And as far as insulation, what should I do: seal to the trim outside, put some foam around the new window, then seal on the inside? Any pieces of wood to put on the inside, or once the new window is screwed in, just seal and that's it?

(PSSSSST)....Don't say "foam" to Lefty.....you'll get him up on a soapbox ! :) ahahahahaha...

Seriously, don't use the "Great Stuff" type polyurathane foam or you'll bow your window to where it won't work if you're not REAL careful......they do make a latex foam ( called Door and Window foam) that doesn't expand as much and remains soft afterwards instead of getting rock hard like GreatStuff.....or use the tried and true: strips of fiberglass insulation stuffed into gaps ( and don't overdo that either )

But let's go back to your original post a minute......

You said you have "replacement" windows that have a nailing flange......technically, that is a new construction window....true vinyl replacements don't have a flange....and they also are already pre-drilled on the side jambs for screws. The holes are located generally behind a cover at the bottom outside sash track, and the upper inside sash track. The cover hides the screw heads later when reinstalled.

As to wood inside, IF you have measured your replacements correctly, you'll have to pull the inside stop moulding off ( the strip of wood that keep the inside wood sash in place normally) to get the vinyl window in place.....the vinyly window SHOULD be 3 1/4" deep >IF< you got the right type window and that just happens to be the thickness of two wood sashes, so your replacement will go out to the outside stop ( what holds the outer sash in place ) and you put the inside stop moulding back in place after you caulk around the window-to-old-wood-jamb point.

If you don't have holes or a cover to hide the screws, you could drill a 3/8" hole in the FIRST layer of vinyl in the sash track in those locations.....just drill deep enough to go thru the first layer, but not the layers on below that. Then your screw will countersink on into the hole, but the lower layers of the multi-chamber vinyl will catch the screw head and hold the window in place. They also make a white vinyl cap that fits a 3/8" hole, so you can hide the hole....look at hardware stores or woodworking catalogs for them.

WOW! This is invaluable info. I won't replace the window today, probably in a little while, so that's great great information. When I went to LOWE's here in southern california, I couldn't find any vinyl windows that don't have a flange. They window guy suggested that I just cut off the flange, and discard. I'll ask them again, though (I can exchange the one I have). Your explanation of new construction vs replacement windows makes much more sense than any of the store's employees. Thank you!

Now as far as the insulation: Do you:
1) Place caulk on the interior of the exterior stop moulding, where the window will rest.
2) Insert and screw the window in place.
3) Place fiberglass/low expansion latex foam between the window and the casing.
4) Seal with caulk.
5) Nail the interior stop moulding back into place.

Correct?

Once again, thank the both of you for all this info.

The guys at Lowes didn't know much ????? Wow....Imagine that !!! ahahahahaha.......you're actually lucky to even FIND any.....at our Lowes, they scurry like cockroaches when a customer approaches, scared they might actually have to do something :)

I put the window in first, then caulk the inside corner created by the vinyl window meeting the outside stop, not "bedding" a caulk layer to set it in like you describe....doing so and if you have to shift the window any is gonna make a mess on the outside new window frame....secure first, caulk later.

Other than that, yeah that's pretty much it.

Lowes there SURELY carries custom replacements....if not, shop around other places.....look in the yellow pages for any aluminum and vinyl supply place.....best place to look for replacements and get somebody that knows something rather than a BigBox store.

Click back thru about a years worth of posts here......I and others have posted a LOT of valuable info on how to measure and replace windows. Worth the time.

Thanks Andy. The guy at Lowe's was actually pretty helpful, except for the fact that they didn't seem to carry replacement windows. I'll look somewhere else.