bay addition

[dwh039]

want to add a small addition to our kitchen. the addition would extend out under the soffits of the house (14") and would be 6-7 feet wide. The exterior wall will have a window and door added. So basically it will be a box or bay addition sticking out the side of the house. What is the best way of building the floor. Do I cut the header at the end of the floor joists and extend the joists out? or do I just use hangers and add the joist to the floor header (the one that is sitting on top of the concrete basement wall) from the outside? Thanks for any replies.

 

[glennjanie]

Hello DWH, and welcome to the Fourm:
I'm picturing your bay being made of two small windows on about a 45 degree angle; one on each side, with a larger window in the middle.
Another way they are sometimes built is with one wide window and two narrow windows squared on the end. I will answer for each type.
Type 1. I would cut the header at the widest point of the large window, extend a joist out on each side of that window, put single joist headers on each angle part and a double on the straight part; leaving the rest of the existing header in place. You would not have any part that makes the sub floor span more than 13" which would be a strong support.
Type 2. Again cut the header at each end and extend a joist out from each end, use a double header between the two and you will have sufficient strength to hold the addition. Also leave the existing header in place.
For either one, if the joist location you need does not land on an existing joist, you can go 4' to 6' into the existing floor space and add a block across between the existing joists then fasten the new joist to that block.
I turst that is clear enough but, if you have fruther questions, post back and we'll go at it a different way.
Glenn

 

[Square Eye]

For only 14" I would be very tempted to not cut the rim joist..

You could get a metal fab shop to weld up a few large metal brackets that would sit on the footer and bolt through the foundation. You'll still have to have an 8 - 10" header across the top of the addition where the existing wall is now, so... exactly what will be the gain?
Make sure you know exactly where the soffit will be in relation to the door height and the window height. The soffits are very low on my house because the roof pitch is high.

Consider everything before you start cutting.

 

[dwh039]

For only 14" I would be very tempted to not cut the rim joist..

You could get a metal fab shop to weld up a few large metal brackets that would sit on the footer and bolt through the foundation. You'll still have to have an 8 - 10" header across the top of the addition where the existing wall is now, so... exactly what will be the gain?
Make sure you know exactly where the soffit will be in relation to the door height and the window height. The soffits are very low on my house because the roof pitch is high.

Consider everything before you start cutting.

I was actually thinking about doing that as well. I could easily weld some brackets myself, but I wasn't sure if this would meet code or not.

 

[Daryl in Nanoose]

Why not just pour a pad of concrete and drill in and set the rebar into the exsisting foundation and go from there.