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Terry1
Split Floor Joist Question
Terry1

I've begun to fix the open issues in my 1921 home. One of the 1st floor floor joists is split at the notch that was cut into one end. The split runs about 4 feet. I'll probably have someone either sister the bad area or possibly replace the entire 11' joist. In the meantime I thought I'd glue the crack, jack it into place and install a joist hanger.

The problem is that every joist has a small wedge removed right under the "tab" portion that plugs into the center beam. (Sorry about the terminology. I don't know what some things are called.)

Anyway, I was planning on using a Simpson LU28R-18 old work joist hanger on the 2x8 joist. Because of the wedge that's removed, there would only be about half an inch of the bottom of the joist that would actually sit on the hanger. One other potential problem would be that 2 of the joist nails happen to line up right at the split so only 4 of the 6 joist nails would give solid support to the joist. The 8 that will nail into the center wooden beam will be fine.

So my question is should I just go ahead and use the LU28R-18 and be happy that at least it has better support than it has had for the past who knows how many years (we've had the house for 2 years and it's always been this way), or is there a better way to improve the support?

Here are a few images. One shows the split joist. Number two shows an intact joist (that dark line near the top is discoloration, not a split), also showing the wedge cut out. Again all the joists have this removed. The third shows a quick drawing of how only about half an inch of the joist bracket would support the bottom of the joist (although the nails would also give some support).

Thanks for any assistance.

Terry

Split 2x8 Joist

An intact joist showing the "wedge" removed under "tab". (Sorry about my terminology :o)

Top shows how hanger (purple) would only support about 1/2" of joist at bottom due to removed "wedge"

HandyAndyInMtAiry
Re: Split Floor Joist Question
HandyAndyInMtAiry

Terry,
You are not alone, I had the same thing in our house. Our house is now 126 years old. We had a few joists that were, not as bad as the one you have shown, but still had cracks. I went above and beyond with the repair. The joists in our house are 2x12's I had a welding shop in town create some "U" shaped pieces of steel 10" tall on the sides to fit the joist width, and that are 4 - 6 feet long using 1/4" steel. I also specified they drill holes in the sides of each and hold across the bottom side. The holes in the sides are for sliding a 1/2" bolt thru. These are every 6 inches, and the smaller holes along the bottom side of the "U" are every 4 inches. I used some structural lag screws to come in from the bottom side. This is to pinch the joist back together. I glued the crack before installed the "U" shaped steel. I then used a couple jacks to ensure the "U" is nice and tight, as far up the joist as possible. I then drilled holes into the bottom side of the joist to screw in the lag screws and then drilled holes in the sides, from side to side, to slide the 1/2" bolts thru. After all this, I use joist hangers that were sized for double joists. I then installed the joist hangers on each end. I did of course sister a couple pieces of 2x12's on both sides of the joists where needed. I places one piece basement jacks under the areas that I modified the joists. On the other joists, that were not cracked, I sistered a 2x12 on each side, gluing and bolting. Using the jacks to level the floor, this worked perfectly. I hired a young man to help me, and this took us about a month of saturdays to complete.

Hope this gives you some insight and ideas.

Handy Andy in Mt Airy NC
Andrew

Jack
Re: Split Floor Joist Question
Jack

If it were me, I would glue and nail the split piece in place then sister a piece of steel plate slightly longer than the split. Drill nail holes and drive nails near the top and into the split off piece.

Jack

keith3267
Re: Split Floor Joist Question
keith3267

You can take a piece of 1x6 that is as long as the center beam is tall. Cut a 2" wide notch from the top down to the bottom of the notch on the joist. This should fit up against the center beam and surround the joist as if the center beam were suddenly 3/4" wider at that point. Glue and nail/screw this in place. Now your joist hanger will be an additional 3/4" out so that should give you 1.25" of support.

Be sure to use 16d nails or 4" long screws to attach the hanger to the collar so they go well into the center beam as well.

I would also glue the crack and use either flat steel plates to support across the crack in several places, or take more hangers, hammer the wings flat and just use them as braces in several sections along the crack.

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