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  1. #1
    Join Date
    Jun 2009
    Posts
    2

    Default Replacement Windows

    I'll soon be replacing some of the double-hung windows on the north side of a 100+ year-old farmhouse. I've read up on how to do it and have been looking through this forum. And I've watched the video on thisoldhouse.com. But I have a question: The void outside the frame where the window weights hang is huge. If I'm screwing the replacement window to the frame of the old window is that going to be strong enough to hold the window? Or should I use screws long enough to span the void and screw into wood on the other side of the void? I was also thinking of filling the void with blocks of wood and screwing them to the house framing, then attaching the new windows to them. Any thoughts or suggestions?
    In the video, Tom Silva fills the window weight void with spray foam. In addition, he drills holes in the bottom of the frame and fills under the sill. I've been reading about not using expanding foam, but instead use the mildly expanding type for windows and doors. With such a large void, am I going to need multiple cans of foam per window? Or can I use the greatly expanding foam for the voids on the sides and the other type for around the window itself?
    Others have written to use insulation to fill the voids, but that's not going to stop the drafts. So I'm definitely looking towards using the foam.

  2. #2
    Join Date
    Jun 2007
    Location
    Fayette County, Ohio
    Posts
    5,622

    Default Re: Replacement Windows

    When you use highly expandable foam in a closed box you are at risk of it expanding and bowing or blowing out one or more of the sides.

    Screwing into the 1 by material should be sufficient. You have the screws, the friction fit, and the caulking or trim all holding the window in place.
    Jack
    Be sure you live your life, because you are a long time dead.-Scottish Proverb

  3. #3
    Join Date
    Sep 2009
    Posts
    1

    Default Re: Replacement Windows

    Our loveable old house has all of it's original 13 windows - which are not so loveable. They need to be repainted, repointed, reglazed and 4 sills need to be replaced. I can't clean the outside windows without a 20 ft ladder. Even with old fashioned homemade windowscreens and storm windows ice still forms on the inside of the windows in winter, is drafty, and still lets bugs inside in summer! We are getting estimates on vinyl replacement windows, hoping to decide soon so we can use the $1500 credit this year, but we're uncertain. We cannot afford expensive windows, but have found someone who claims he will replace the sills, cover the outside moldings, custom fit to size, duplicate 6-over-1 lights, all for $5,600. Will it ruin the character of the house? Will vinal windows torque in the frames, shrink and expand and cause problems? Are expensive custom windows necessary as opposed to this kind of replacement window? And what should watch out for? Will the cladding over the outside of the sill and window moldings promote future rot? Do many old home owners recommend replacements (particularly of this type) or do they regret them? Thanks for your time.

  4. #4
    Join Date
    Sep 2009
    Posts
    37

    Default Re: Replacement Windows

    Quote Originally Posted by JLMCDANIEL View Post
    When you use highly expandable foam in a closed box you are at risk of it expanding and bowing or blowing out one or more of the sides.

    Screwing into the 1 by material should be sufficient. You have the screws, the friction fit, and the caulking or trim all holding the window in place.
    Jack

    Jack is correct. You NEVER use high expansion foam for windows. This will bow the frames in and cause problems with opening and closing the windows. Always use minimal expansion foam or foam that says it's for windows and doors. As far as attaching the windows to the rough opening frame, you have a couple of options depending on the type of window you got. If you got a nailing flange on the window, you will bend it out so that it goes against the outside of the house. Through this you will attach the window to the house. If you did not get a nailing flange you need to have some sort of shimming between the rough opening and the window frame itself. I would honestly take out everything pertaining to the old windows all the way down to the framed in rough opening. Then you would need to add some sort of blocking and shims to come out to the size of the window frame. If you leave a gap between the window frame and the blocks that you are attaching it to, you will end up bowing the frames outward by the screws pulling on it. Don't forget, no matter which way you attach the window to the house, always shim the bottom side of the window frame to support it on the rough opening from sagging.

  5. #5
    Join Date
    Jun 2009
    Posts
    2

    Default Re: Replacement Windows

    I replaced the windows over the weekend. I used the expanding foam in the window weights void. I did it in multiple sprays, letting it expand and start to cure before doing the next level. (I had all weekend and it was nice weather) The first spray was up to the bottom of the opening for the weights. For the second one, I held the piece of wood that goes over the opening for the weights in place, tilted it back at the top and sprayed in to the top of that piece. Then I screwed the piece in place. The foam continued to expand upwards in the shaft. The final spray was from where the pulleys go through up top. Only on one side of the five windows I replaced did the foam expand out through the pulley holes. I taped a plastic bag under that hole and let it expand and fall into the bag.
    I used minimally expanding foam between the windows and the old frame and everything worked out fine.
    I was able to leave the storm windows on the outside, so now there are three panes of glass. The only problem I had with that was trying to caulk the outside of the window where it meets the blind stop. The frame of the storm windows got in the way and I couldn't get the tip of the caulking gun in close enough. I solved that by taping a piece of flexible tubing onto the end of the caulking tube, which extended its reach.

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