Big Window?

Started by simon, November 24, 2004, 01:56:30 AM

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John   ...

 Going to frame the front wall in a couple days  ... building the 14 x 24 flat roof ..     Planing to put a big picture window in the front to look out over the ocean. A friend owns a glass shop so glass come cheap , would the cantlevered floor joists have any problem holding a 6x12 window ?
Can u for see any problems? ..Any idea what sized header to use...
                                       confused again..Simon ???


The header, as a first guess, might be double 2x12 with 1/2" ply or OSB in a sandwich. This assumes it is in the 24' long side of the house. Use double studs for the trimmers to support the header and make sure you have solid blocking and bearing below. You are putting half the load of the entire wall on two points. If you can, double the joists under this load.

I'm not an engineer and have not done calcs on this. Heavy snow loads could change things.

Ryan B

A few more considerations-
-Due to the large surface the glass needs to be thicker to resist deflection from wind load. Thickness and tempering options based on sqft of glass and wind speed are given in IRC 2000 (I suspect your glass buddy has these).
-Window frame construction to resist wind load also should be given the same consideration. Also if the window will see direct sun the frame has to be made for larger changes in glass movement.
-Most important is the king/trimmer/header connection to the top and bottom plates. These must be sized for the added load (hurricane straps and or angled connection brackets). Imagine 6' of wind load (12/2=6) being transferred to those connections. Normal studs would only have 1.5' wind load based on a common height.

Ryan B