Floor Joist Repair

a two story home, I took out the ceiling and noted a cracked joist that ru ns a 20 foot span under my kitchen and dinning room, there is no center sup port and it is supported at the ends on top of cinder block and set in conc rete. The crack is 8 feet from the wall in my laundry room which is under m y kitchen and extends approx. 3in from the bottom edge into the beam across a 1 foot span. The beam is a 2x12x20. To repair this I want to sister it a nd build a frame to support it in the middle which I can accomplish by addi ng a door way to the laundry room. I want to put king beams on either side approx. 48in apart and have a 3 foot opening into my laundry room. I was go ing to use 2 stacked 2x4s to make the header. My question, Is this adequate support? What can I do to make this better? I just want to make sure I do this right, Thanks for your help.

You call it a joist in one place, a beam in another. It would seem if it's a joist, then with a 48" wide support under it, that support over the door will not carry just one joist, but two or more. Really need more info on t he whole situation. A 20 ft span with no mid-span support doesn't sound right , so I agree, you're on the right track. All those joists would need mid-span support.

John T.

Now that we know where the crack is, you will be arrested for possession of an illegal drug substance. It was nice of you to reveal the location of this narcotic, so we can swiftly put you in prison without further delays.

The FBI

Sister the joists full length with 2X12. If you can't get 20 footers, use 16 footers on both sides, staggered end for end, plus 4 footers to fill in the length - bolt and glue. The header above the door opening is stronger with 2X4 lumber set upright, 2 or 3 wide, than on the flat

I read it as a 1 foot long crack in a 2 x 12 .. .. not near to the edge or to the end. My first thought was sandwich it with 5/8 plywood - - 3 - 4 feet long - glued & screwed .. And I thought that might be over-kill ... dunno. John T.

On Wednesday, January 3, 2018 at 10:00:16 PM UTC-5, snipped-for-privacy@ccanoemail.ca wr ote:

of a two story home, I took out the ceiling and noted a cracked joist that runs a 20 foot span under my kitchen and dinning room, there is no center s upport and it is supported at the ends on top of cinder block and set in co ncrete. The crack is 8 feet from the wall in my laundry room which is under my kitchen and extends approx. 3in from the bottom edge into the beam acro ss a 1 foot span. The beam is a 2x12x20. To repair this I want to sister it and build a frame to support it in the middle which I can accomplish by ad ding a door way to the laundry room. I want to put king beams on either sid e approx. 48in apart and have a 3 foot opening into my laundry room. I was going to use 2 stacked 2x4s to make the header. My question, Is this adequa te support? What can I do to make this better? I just want to make sure I d o this right, Thanks for your help.

Could also be a shear crack and nothing to worry about. Get someone who kn ows what they're doing to look at it. This is not DIY stuff.

And IF you DIY, rather err on the side of extreme overkill than marginal deficiency.