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scrappy25

Box Boy crosspost from windows forum- logistics and who builds?

scrappy25
10 years ago

No response on the windows forum for 2 days- crossposting here for advice.

My house was built in 1979.
I would like to replace my south facing eating area window (two Anderson narroline double hungs 39" wide x 45" tall, total 78" wide x 45" tall) with a box bay that can be used as a window seat for the breakfast area. Currently the window is 36" off the floor. Ideally a box bay would be 16" off the floor but I am worried about tempered glass requirements that are in effect for glass surfaces less than 18" from the floor. If 16" off the floor, that would be a 78" wide by 65" tall box bay. If I use the same width window I believe that the existing header can be utilized.

Questions
1. One possible problem is that the window is already in a 2 foot bump-out from the house that is 18 feet wide to include the kitchen and eating area. Am I running into structural problems by adding a box bay? The existing roof overhang including gutters is 24" so the box bay could be 18 inches deep (including the 4" wall thickness) for a nice seating area without requiring a new roof.
2. If I use single or double hung windows where the lower pane is 36 x 30 inches, can I avoid the tempered glass issue since each pane is less than 9 sq feet? Thinking of using fixed panes for the smaller side windows.
3. Is there an existing vinyl manufacturer that makes box bays or do they have to be constructed on site? If constructed on site, could this be created with stock windows or do they have to be custom?
4. Definitely Low E. Any other recommendations for a south facing window?
4. Can a good window company take care of all this or do I need a general contractor? I am in the Baltimore area so any recommendations are appreciated. (ie if WOW could do this project I would be thrilled)

thanks in advance for your advice!

Comments (21)

  • snoonyb
    10 years ago

    There is another part of the regulation used in the determination where tempered glass is required and that is that the glazed area cannot exceed 60" in height.

    Do you know if there is a post between the two existing windows?
    Do you know the height of the header?

    If you choose a wood or vinyl unit, and it can be ordered as a complete unit, there will be a bottom window mullion which will be at least 2" wide, plus the height of the lower frame member, which should bring the glazing well above the 18" minimum.

    A competent handyman with a helper or two can easily accomplish this.

  • sombreuil_mongrel
    10 years ago

    If I'm reading you correctly, you are going to have window glass as the backrest for the seating? Or windows starting above the backrest height? (which seems much more user-friendly, and you don't have to worry about aunt Brunhilda's butt shattering the glass.)
    Casey

  • scrappy25
    Original Author
    10 years ago

    Thanks,

    I currently have two double hungs starting 36" above the floor. In this picture you can see the 2 foot bumpout wall on the right, in line with the edge of the white cabinet. The recessed lights are just inside the existing 2 x 12" header for the kitchen/breakfast area bumpout.

    I was thinking of two double hungs side by side down to the window seat cushions (16-18-20"?). Similar to this picture from dlgibson.com, but only down to the window seat level. The box bay would not continue to the floor.

    {{!gwi}}

    Casey, you have a good point, but almost every picture of a window seat on google images is down to Aunt Brunhilda's butt (LOL for that visual). Also, I was thinking that the window would be ordered in one piece including the seat portion. If the window does not go down to the seat that seems more like on site construction? Is this what you are thinking of?

    snoonyb,, there would be a post between the windows I think, still am unclear whether this would be best installed as a factory mulled window or as on-site construction. Existing header for the existing bumpout is probably dual 2x12's from our peek through a hole that I cut in the kitchen soffit a while ago.

    I did not understand the first part of your post completely but if I use double hungs I believe that the top of the bottom unit is 30"+18" =48" so it will not be 60" above the floor.

    I am having trouble finding a manufacturer that will make a 90 degree box bay with double hungs. I find them with casement windows but I am pretty sure that casement windows are large enough to force me into tempered glass.
    If I cannot find a manufacturer, would a window company have the carpentry skills to build this? I need the trim done also to tie into the siding.

    An alternative is to not have the sidelites like in the 3rd picture, just the double hungs on the back of the box bay,

    LMK what you think for logistics and construction.

  • snoonyb
    10 years ago

    What you are looking for is pretty common from lumber yards, here on the left coast, as a unit, to be inserted into a prepared wall opening.

    Depending upon how you are attaching and supporting the it, framing or corbels, will determine the depth of the top and bottom plywood shelf.

    As you can see in your examples the glazing will be well above the 18" above the floor, with a 16" seat height.

  • _sophiewheeler
    10 years ago

    I don't see what your resistance to tempered glass is. It's a safety issue, and you NEED tempered glass for your application. Kids and highjinks, or even an older person misjudging the distance are facts of life around a kitchen table. Where I am, the AHJ would consider the surface distance to be the window seat, not the finish floor height, and all applications involving a seating area require tempered glass. Would you rather cut someone's artery and have to call an ambulance if they lean back too far or would you rather just sweep up some crumbs of glass and make a joke. It's criminally negligent to not do this with tempered glass, and you can bet that what anyone who falls through it and cuts himself will say so. Your insurance company might just get out of paying the claim and it be all on you.

    If you can't afford to do the project properly, wait until you can.

  • scrappy25
    Original Author
    10 years ago

    Hollysprings, thank you for your terse and valuable advice. I will take it to heart. Any idea what the cost of additional tempering is? Would only the lower half of a double hung need to be tempered? Although if I want tempered I could move to the casements.

    snoonyb and casey, thank you for your input. Based on your advice I have refined my thoughts as to the construction of the bumpout and finally after much searching found a picture of my idea. It is from a Fine Homebuilding article, "Designing and Addition that Looks Right", 2009.

    As you can see, the windows here are high enough that Aunt Brunhilda will not have a problem. Is this type of structure something that can be purchased at a lumberyard and set into the opening, or is this site built?

    thank you
    Nancy

  • _sophiewheeler
    10 years ago

    It's site built by a carpenter if you want it to look the best and fit the site conditions, as well as a budget. Only very small box bays or "garden windows" are going to be feasible to purchase assembled. It's a weight and racking issue. You'd need a heck of a lot of bracing and a small crane for install if you had something that size pre assembled.

  • snoonyb
    10 years ago

    Really hollysprings;
    "Where I am, the AHJ would consider the surface distance to be the window seat, not the finish floor height, and all applications involving a seating area require tempered glass."

    So, the "window seat", would be required to meet floor live and dead loads?
    What about the 16" height, which exceeds the max. riser height, or the 24" seat depth, which is below the required landing width?

    Or does the code, not matter?

    Or is it the abdication of personal responsibility?

    You are also mixing commercial and residential applications, and chairs, it's a window seat, in a residence.

    scrappy25 Either, or, and the lumber yards I would purchase from are not in the least bit concerned about "racking" and I've already addressed weight.
    These are a common installation here on the truly left coast.

  • scrappy25
    Original Author
    10 years ago

    OK, I really appreciate everyone's help. I will ask at my local lumberyard. I am probably going to get tempered even if it is not code, due to safety factors. I do want the windows somewhat lower to the ground because I see from these pictures that I posted that my windows are somewhat short and squat, and the pictures that I like have a vertical axis longer than the horizontal. You all have been really helpful, thanks.

    Snoonyb, is the "left" coast the west coast? I have not heard that term before.

  • sombreuil_mongrel
    10 years ago

    This could be executed so that the loads could be borne by shear panels concealed within the design, if proper fasteners and adhesives were deployed. Even if you built it like crap, it would not fall down, but to keep it square and sag-free will require some ingenuity. Cantilevering the floor joists to carry it would be the way to have built it from new, but that may not be an option.
    You are going to basically build the wall section below the window as a truss, tied into the walls with solid 3/4" plywood fins well-affixed to very solid corner posts which have to perfectly mate with the top and bottom plates of the main walls. The 3/4" plywood overlaps the corner posts 3 1/2 " (or 5 1/2 if 2x6 walls) I'd maybe go so far as to make the wall corner posts out of LVL or structural fir, and attach to the plates with metal brackets and lags so you know they will never work loose.
    Then the "truss" would get bolted/glued to the plywood fins, the remainder is infill framing to make up the R/O's, and create the seat, etc.
    That's how I hang box bays off of wall framing.
    Casey

  • scrappy25
    Original Author
    10 years ago

    Casey, I am in the medical field so your words are a little greek to me, but in my research I came across these diagrams posted by "Tom" on fine homebuilding forum halfway down the linked post. I will also insert his drawings here directly so that it is easily visible. Is this what you are describing? If so, which part is the truss and are the plywood "fins" a frame of plywood that juts out from the house framing? Does Tom only have the bottom part of the plywood "fins" shown in his drawing?
    The views are from the inside of the window.
    Do I need a structural engineer to sign off on this small project?

    I found another diagram from studiohamlet.com, "Structural solutions for small bumpouts" which may represent what you are describing.

    In this last drawing, I am confused by the "Sidewall detail". Is that a cross-section looking from the side, or looking from the top? Is your "truss" the "torsion box hung on a ledger" described here?

    Thanks for your patience.
    Nancy

    Here is a link that might be useful: Box Bay framing

  • scrappy25
    Original Author
    10 years ago

    light bulb moment for the "sidewall detail" of the studiohamlet.com diagram. It is a "top view" with the bumpout on the right extending inferiorly on the page. The reason I was confused is because Tom's diagram from the finehomebuilding forum has the sidewalls partially sitting on the house framing, INSIDE the wall opening, but the studiohamlet.com diagram has the side wall OUTSIDE the wall opening, only the inside 3/4 plywood projects into the house framing. I think I prefer the hamletstudio version because it leaves a wider window opening. Casey, which one do you use?

    Am I right in thinking that if I keep the box bay the same width as the existing window, that no new beam is needed above the bumpout opening?

  • snoonyb
    10 years ago

    CA, unfortunately, is even further left than the current administration.

    I am not.

    The method that I employ differs from "sombreuil_mongrel" and that pictured, in that the supports slope or are angled down to the sil, which eliminates the "undershot" and the forgotten affect of moisture accumulation from landscape plantings.

    There is more than one way to skin a cat.

  • sombreuil_mongrel
    10 years ago

    My method is closer to the magazine scan; they engineered it to carry more load, i.e.: a water-filled soaking tub, and perhaps some of the roof load, though that's not completely clear.
    They do show my idea of the fins (in plan view, looking down from above) so you can see how they are fastened to the framing of the main wall, and if the posts are fixed, the plywood cannot rack, and the box beam is thereby supported firmly. This is only for shallow box bays like you window seat, not for a floor.
    Casey

  • scrappy25
    Original Author
    10 years ago

    Thanks all, your answers have been really helpful in getting my thoughts formed on the best design for this box bay seating area. If the local lumberyards cannot provide what I need, I will favor Casey'splywood fins to get the larger window size.I am sure that whatever carpenter/contractor I choose will have his/her favored support, whether a box or angled. I don't think I have the landscape problem since there is a deck on the exterior that is a few inches below house first floor level, and that deck is about 2 feet off the ground.

    Appreciatively, Nancy

  • scrappy25
    Original Author
    9 years ago

    HI Everyone, I wanted to update on my bay window in the eating area. It was installed yesterday and is beautiful, what a difference it makes to have the bumpout and the larger window! My previously planned kitchen expansion has contracted to just this but I am super pleased with it.

    I found online that Sunrise windows are well regarded and has a "projected frame" window that is made at the factory, so emailed them. They put me in touch with their local contractor. Many emails and two meetings later (I also had a door replaced and a new exterior door placed), the window part was constructed in one day. I asked for foam insulation to be added all around and then covered with Azek to be sure that the window stayed warm. Sunrise only offered this type of bay with the windows going all the way down. My next project is to create a flip up wood shelf that can sit on the seat when closed and act as a back support when opened.

    Total cost for the window, extra insulation, trimming with Azek,and installation is about $5000 all told and they considered the corbels sufficient support, so no torsion box needed. Some electrical had to be moved down also. The header and window width is unchanged.

    Absolutely worth it and it's amazing how easy the new windows and doors are to operate. My patio door went from a two handed, full body planted heaving opening effort to single finger opening. The new windows in the bay move with a few fingers. When they are closed up the garden sounds completely disappear, unlike our old windows . Super low air infiltration.

    Next is the kitchen remodel in the existing space, finally!

    Before

    After

    This post was edited by scrappy25 on Wed, May 14, 14 at 9:33

  • renovator8
    9 years ago

    The building code is not the final word on safety but it is a good place start.

    Safety (tempered) glass is only required where a very large force is likely to be placed against glass and that generally means where someone might be walking fast and fall against the glass. A force less than that should not break window glass.

    This rule would not usually apply to window seats and it only applies to the bottom edge of a glass panel greater than 9 s.f. in area that is within in 18" of the floor and if the top edge is within 36" of the floor. A floor means a walking surface not a seat and it must be within 36" horizontally of the glass.

    The more important issue is if you think someone might hit the glass very hard and be injured. The cost of tempered glass for two windows should not be an issue.

  • scrappy25
    Original Author
    9 years ago

    thanks, we got the tempered glass for the bottom two panes just to be on the safe side. A small price for peace of mid.

  • mrtanman
    9 years ago

    @ Scrappy , I am looking at doing something very similar to your project . Basically, I want to replace a " walk around" bow window (110 inches wide ) . The window is under a "covered porch " Can you tell me did you need to pull a permit for the project ?

    thanks

  • scrappy25
    Original Author
    9 years ago

    Not sure if we had to have it permitted but I did since we had some windows changed to doors elsewhere in the house as well. Best to call your county housing inpection office to ask. Ours is very helpful to homeowners.HTH

  • renovator8
    9 years ago

    Any change in a code controlled element should require a permit and windows are code controlled in terms of safety glass and energy efficiency.