Adding a large window - structural question

[johnnyreb]

We're thinking of adding a large (4' x 8') window to an existing log home. I'd like to have just a single pane of glass but I'm concerned about the structural integrity of adding this.

Here's a pic of what I'm thinking of doing...

http://s17.beta.photobucket.com/user/harleye/media/2012-12-04190954.jpg.html

The X is where the window would be placed. Basically I'd like it centered between the molding of the door on the left side and the end of the wood floor at the bottom right of the photo. The wood beam that you see at the top spans the length of the house and supports an upstairs loft. I'm concerned that removing that 4x8 section may cause problems with the structure.

Would those 2 lengths of beams above the proposed window be enough support? Although I'd rather just have a single pane of glass, would I be better off with a "3 piece" window something like this that would have the vertical support between each pane?

http://s17.beta.photobucket.com/user/harleye/media/IMAG0041.jpg.html

[johnnyreb]

Don't know why my pics didn't show up in first post.

Here are the links...

This is what I'd like to do with one pane of glass - http://i17.photobucket.com/albums/b75/harleye/2012-12-04190954.jpg

And here's the second photo with the "3 piece" option - http://i17.photobucket.com/albums/b75/harleye/IMAG0041.jpg

[StressMan79]

well, rebel.

you can't count on the beam under the girder, since there is a splice right in the middle, I don't think that the one beam below it will be adequate. Your "log" house will settle, so you can't reinforce the sides with steel. in short, you can do it, but it won't pass my analysis muster. Oh, one more thing, generally windows look best if the top lines up with the top of the doors. You are already low there, Why don't you put two thinner windows separated by a 3x girder width centered in there?

-Peter

P.S. you have to copy/paste the image tag from photobucket to get the pics to post. Like this (without the star):
http://i17.photobucket.com/albums/b75/harleye/2012-12-04190954.jpg
http://i17.photobucket.com/albums/b75/harleye/2012-12-04190954.jpg

[rreidnauer]

Single piece of glass? Not easily. At best, you'd have to cut back those two courses above the window opening, and install an engineered beam (paralam) and vertical structure on either side of the window to carry load down to the foundation.

Three separate windows with load carrying verticals in between them would probably be your best option.

That splice just above the window still would concern me though, with so much load being carried by the second floor girder.

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[rocklock]

Boy, there are a bunch of questions that need to be asked...
1. How thick is your wall?
2. Do you have stuff running through the walls?
3. Has your settling stopped... How long has the wall been there?
4. How can you support the floor above while you are cutting the window?

If these are 'Logs" are six inches thick, I would want to support the floor above while making windows. I personally would want to have vertical 4 by 6 bucks for my windows. In my case, even though my logs do not shrink, I have 4 by 10 bucks for all my windows and doors.

Log homes generally don't have lots of windows because of support problems... except mine. I have 21 windows, sky lights and doors.

[Timberwolf]

+1 to the responses above. Because of the girder, spliced beam, height, gable vs side wall (not to mention what is in the walls) etc, I would not go with an 8ft window there. Perhaps two 4 foot windows centered in the spaces between the girders and the other openings. Even then, I'd be concerned about the structural integrity of the wall and would want an engineers stamp (may be required where you live, and isn't a bad idea regardless).

Hey Rocklock, that's not fair! ;) I have three 8ft windows and one 8ft door one of my walls alone. :)

[johnnyreb]

Boy, there are a bunch of questions that need to be asked...
1. How thick is your wall?
2. Do you have stuff running through the walls?
3. Has your settling stopped... How long has the wall been there?
4. How can you support the floor above while you are cutting the window?

If these are 'Logs" are six inches thick, I would want to support the floor above while making windows. I personally would want to have vertical 4 by 6 bucks for my windows. In my case, even though my logs do not shrink, I have 4 by 10 bucks for all my windows and doors.

Log homes generally don't have lots of windows because of support problems... except mine. I have 21 windows, sky lights and doors.

1. The inside of the wall that you see in the picture is a flat surface. The exterior of the log is rounded. At the widest point they are 7.5". At the narrowest point they are 6.5"
2. The wiring comes up from the bottom of the walls to the outlets and switches. The window would not interfere with the wiring.
3. The home was built in 1993. I purchased the home in 2007.
4. The "window guy" that I had come out said that they would temporarily brace the beam until the new window was in place.

[Timberwolf]

Before I let the "Windows Guy" take a chainsaw to my house, I'd want a "Structural Engineer Guy" familliar with your style of log home sign off on the plan.

I also agree with Stressman's comment about the height of the window(s), it should be at the same height at all the others (usually dictated by the door height.

[rreidnauer]

Agreed about the window guy's thing. From his statement, he is saying he'd provide temporary support while the window opening is cut, and remove it once the window is in. I'm pretty sure there are no residential windows, even fixed-pane, meant for structural loading. Best to get advice from someone who doesn't have a stake in the profits of it's installation.

I wouldn't do anything along what you're planning without a structural engineer taking a look at it first.

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