I’m going to be building a small addition on the back of our cabin and would like you opinions on the floor and foundation layout. The cabin is off grid in the mountains and we get snow there.
The existing cabin has three 4x6s set on three piers each. I would like to bolt three new beams to the sides of the existing beams. The other end would set on piers. The load from the ridge beam would be slightly off to one side of the middle beam, will this be ok? Also the right wall will be supported by a 4×12 header that runs the entire width,96″, of the addition. I will put a pier under both ends. The left wall will have a door in it, should I have a pier under that beam mid span as well?
Please look at the drawings, ask questions and give me your thoughts.
Thanks,
Andy
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I can't open the drawings, format unknown. You may want to format them in .gif or .jpg
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Please try these.
Andy
Just bringing this to the top, hoping for some help.
Maybe, possibly, probably...lot of missing detail. Not much labeled in drawings. I can surmise...be back later perhaps after I make some calls, etc.
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What do you want labeled?
The beams are 4x6, they run vertical in the drawing, 2x6 joists run horizontal in the drawing. The parts with the diagonal lines are the ends of the existing 4x6s that the cabins 2x6s set on. The circles are where the footings would be. There are three footings under the existing 4x6s. The only footing not shown is the one that might go under the left most beam, which is where the door is going to be. I would bolt the 24" overlap of the 4x6s together with 1/2"d bolts. In the sketch up picture you are looking at the cabin with the addition on.
Clear as mud?Andy
I was typing as you posted.
To the right of the center beam you will notice a circle representing a pier. There is also one at the wall of the cabin. Those two will be right under the 4x4s that support the header. The upper floor will be a sleeping loft and I planned to run the joists perpendicular to the long wall.
Thanks,
Andy
So joists would be same direction as the beams under the floor? That would take some of the floor load off the jacks supporting the header, but now you transfer the floor load all to the outer single joist on the left bottom position, which would make me want to double it up and be certain of the hanger size and fastening there.Also I see floor joists are 2x6? Can they be any deeper?Most of your explanation is as I surmised. It is never wise to assume in structural work tho.
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Yes, the loft joists would be parallel to the floor beams.
I can double up the rim joist or use a 4x6 from corner to corner which is 16'.
I could use a bracket like the simpson cct in the pier to hold the beam and rim joist or bolt heavy duty "L" brackets to the beam and rim joist.
Right now there would be about 10" between the dirt and the bottom of the floor joists, using 2x6s. I can't raise the floor, but I could excavate down some to create a larger distance.
The cabin's floor is 2x6s at 16" centers on top of 4x6s at about the same span, that's why I went with them for the addition. Not that what was done before is necessarily correct.
On spot that you haven't mentioned, yet, is the bolted connection between the existing 4x6 and the addition 4x6. Care to comment? The plan was to use 6 1/2" bolts through them. The addition beams would not rest on the pier unless I put some blocking down to the existing pier.
Let me thank you again for you help.Andy
that connection is no bid deal since you are placing piers under both ends of the new. A one foot lapp may be enough. You are only stopping the addition from sliding sideways with that joint.When asking about depth of floor joist, my choice here would be to use 2x8 full length ( what was it, 16'?) and place the center beam with piers under them at the location where the point loads drop down, and double the outer one.
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OK, glad I took time and another look. I had misunderstood a part of that. Still lot of missing detail.
But what concerns me most is not the relation of ridge beam to piers ( whether direct stack or not) but the location of those point loads that support the header. That header is carrying an upper floor and a portion of the roof load. That means a potential for something in the neighborhood of one and a half tons on each point load which lands on a single joist. I would look for a pier directly under each of those locations.
Whether to do that by moving your center floor beam over there or by doing one of several other alternatives I can't say without the whole package.
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