Need some advice here....

[J Levine]

I figured I would try the CSR out for this one since I know there are a lot of DIY guys on this board. I bought my house, which was built in 1993, from the original owner who was one of these do it yourself guys from hell. Meaning everything he touched is screwed up. After almost 4 years I have corrected most of his "improvements" but last night I came across some of his handy work that is shocking. Check out the attached pictures. This guy decided to chop out about 30" of the bottom flange and 1/3 of the web out of two of the engineered floor joists in order to make room for a lighting fixture in the ceiling of the finished basement.

The obvious repair is to get two new joists and double them up against the two damaged ones. Unfortunatly doing this would be a major PITA since space is tight and there are a bunch of electrical lines running through the joists that would have to be relocated. These joists are spanning a 12' run between the foundation wall and a central steel beam.

Alternatively I am thinking about boxing in the bottom flange with cold rolled angle iron on both sides through bolted every 12" and then sandwiching the web with 10" x 1/4" steel plate also through bolted. The damaged section is about 30" wide so I was thinking about using 8' lengths of steel to span the section.

What do you think?

 

[fc3]

Hi Jon

You're not going to like the answer. You have to siamese a joist with the molested one. Drilling through the bottom section weakens it. If you don't want to use wood, you could use a piece of steel I beam. It won't require as much height, so you can push the electric wires below it and just shim it at the foundation and at the center beam.

Who did your building inspection? Guy should be shot for missing that. Or maybe...

Best regards,
Frank

 

[mwph]

The angle iron may be a little over kill. (this comming from a guy who has overkilled most of my home repairs).

How about just sandwiching, use glue instead of thru bolting, the molested joists with some stout lumber or plywood & tie them into the undamaged joists on either side.

 

[Four Suns]

I think you have two options. The good news is I don't think you have to do something as expensive and drastic as you are thinking.

The first option would be to install some LVL beams (you can get them at Lowes or Home Depot... they are green... google it) that are the same height as the engineered floor joists. What you would do is install some LVLs perpendicular to the damaged beam such that the load is transfered to the joists on ether side. Basically, you will be boxing in the light fixture and then completely removing the joist section that is cut. Here's a sketch:

You would have to support the joist you are going to cut on the pieces remaining with some floor jacks but you can rent those for a day at a rental place for a few bucks. It appears you have a drop ceiling so you should be able to do this for less than $100 in parts and rental fees... If you have other duct work in there, this may not work... which leads to option 2...

Look on the side of the joist and find who the manufacturer is. Call them and tell them your issue and get the specs on how to sandwhich the webbing with a solid dimensional beams. There will be a distance from the cut flange you will have to go in and a bolt pattern and glue you will have to use. It's not good to cut the flange like this but you can put something like a 6 foot sister joist sandwich up there and the sheer flow from the solid joist will work through the webbing and down to the bottom good part of the flange. You could hire a local Professional Engineer (PE) to give you a calculation and put his stamp on it... I work with a guy here on my house and for a project like that he would charge me a few hundred dollars for the analysis and proper fix (I actually got my PE in Florida many years ago but never used it or kept it up to date).

My 2 cents.

 

[Nehalennia]

.....morons.........
Gary's idea will do it and properly transfer the load.

 

[J Levine]

Excellent suggestions guys, thank you very much.

Gary I am familiar with LVL's but they had not crossed my mind for this problem. The only difference between your sketch and my situation is that the light fixture runs perpendicular to the joists and the guy molested two of them to do this so I would have to span the gap between two of them with the LVL's. I still do not fully understand how the perpendicular LVL's would be tied into the existing joists and how the load carrying capacity of the damaged joists is transfered to the parallel joists through the LVL. I will follow up on your suggestion to contact the engineered joist manufacturer, I also think getting a PE to take a look is an excellent suggestion and thank you for your thoughts.

 

[Four Suns]

They actually make hangers for the engineered joists and LVLs to tie together... I actually built the house I'm in now (served as general contractor) and will see if I can find some pictures.... but getting a PE involved, as well as having a good working relationship with one, is goodness all around.

 

[SR400DB]

I am a general contractor and what Gary has suggested is the right way to go. The only other item to add is you will need to add web stiffeners to the existing joists in the area of the lvl hangers prior to installation, get a PE or SE and have them draw a simple diagram and get a repair permit from the proper authority to avoid disclosure issues down the road. My .02

 

[jrirvine1]

I will respond to this if only because all of the previous response you have received, no matter how well intended is unfortunately incorrect.

What you have are TJI’s that are like individual “I” beams. The bottom cord and some of the osb webbing has been cut, effectively drastically reducing the load capacity. The bottom cord operates in tension and when totally cut renders it useless. The fix is to restore the integrity of the bottom cord and repair the osb webbing between the cords.

It is not necessary to sister new joists, add steel or header off the damage with LVL’s. I would handle the repair as follows, assuming you do not want to install a totally new TJI.
1- infill the damaged bottom cord with a ripped 2x4
2- repair the osb webbing by sandwiching ½” CDX about 4’ long on both sides of the hole, glue and nail together.
3- take a sheet of ¾” cdx yp sheathing and rip 2 – 8’ pcs the exact width of the joists, which look like about 9.5”
4- glue and nail the ¾” x 8’ rips to both sides of the joist with the repaired bottom cord in the center. Use PL400 glue and #8 nails into the top and bottom cords with the nailing about every 6”.

This will repair the damage while not add too much weight and restore the integrity.

 

[Four Suns]

I will respond to this if only because all of the previous response you have received, no matter how well intended is unfortunately incorrect.

Well... I can tell you that I have engineered joists all over my house and holes are in the floor that are boxed in with LVLs for things such as stairwells, a dumb waiter, an elevator shaft, heating and cooling ducts, etc. and you can box in things like this and retain structural integrity.

 

[jrirvine1]

Well... I can tell you that I have engineered joists all over my house and holes are in the floor that are boxed in with LVLs for things such as stairwells, a dumb waiter, an elevator shaft, heating and cooling ducts, etc. and you can box in things like this and retain structural integrity.

Of course you do, but this is not necessary in this case and would unnecessarily complicate the repair. Also, LVL’s are not needed to header off a single joist as conventional lumber will work nicely, when needed.

 

[wish2fish]

While gary's idea is better than what is there now don't the joist that will help carry the load have to be doubled up? I thought that is what the did around stairs, etc.

 

[Four Suns]

I didn't get from the original post he wanted to remove the light and restore the joists (2 of them are cut).

 

[Four Suns]

While gary's idea is better than what is there now don't the joist that will help carry the load have to be doubled up? I thought that is what the did around stairs, etc.

Depends what is sitting on top of the floor and how big the current joists are.. that's why you should get a PE involved. There are sections in my house where I have 16" webbing and 2x4 stringers on the joists and some of the holes did not have to be doubled up due to the over-engineering of the joists... It all depends...

 

[jrirvine1]

Typically, it is allowable to header one joist only without doubling the adjacent joists.

 

[J Levine]

Thanks again for all the input, it is very helpful. I am going to reach out for a PE or SE. To address Gary's question, I did not mention that I plan on removing the offending light, we were planning to pull them all out to go to can lights this winter. Luckily the moron only did this for one of the lights. He then lowered the suspended ceiling about 2" (on the other side of a boxed beam) so that the other fixtures would clear. Why he did not lower the ceiling when he ran into this problem instead of butchering these two joists I will never know. Even if I remove the light, doubling the two joists would be a bear of a job, not only due to lack of access but the other end of the joists (they are 12' long" is near the main electrical pannel and there are are number of both 110 AC lines and low voltage wire for my alarm system that pass through the knock out holes in the joists. In order to double them I would have to either pull all this wiring out to rerout it or use junction boxes to splice all the lines. I am hopefull that I can use Jim's suggestion above and repair the joists with the approval of a SE or PE.

The joists are marked "Trus Joinst MacMillan Silent Floor Peformance Plus" and are 12" high. A quick web search looks like the manufacture is either out of business or has been acquired.

 

[wish2fish]

Depends what is sitting on top of the floor and how big the current joists are.. that's why you should get a PE involved. There are sections in my house where I have 16" webbing and 2x4 stringers on the joists and some of the holes did not have to be doubled up due to the over-engineering of the joists... It all depends...

what if he decides to put a water bed, refrigerator and a large safe in the room above? :huh:

I can't believe somebody would look at those joist and think that was okay!

 

[jrirvine1]

I am hopefull that I can use Jim's suggestion above and repair the joists with the approval of a SE or PE.

The joists are marked "Trus Joinst MacMillan Silent Floor Peformance Plus" and are 12" high. A quick web search looks like the manufacture is either out of business or has been acquired.

The repair that I outlined has been previously approved by our structural engineer and / or the TJI manufacturer, and has been used in applications where replacement is prohibitive due to access.

Good luck.

 

[J Levine]

Jim

I cant thank you enough for your time and thoughts. I just eyeballed the area again and though I need to R&R some HVAC duct work, I can deffinatly do this type of repair.

Thanks again

Jon

 

[Newbie]

Headering the cut joist to the opposite joists will more than likely require doubling of the opposite joists. You need an engineer to spec the repair but jrirvines suggestion sounds like the best so far. I would extend the packing and sandwiching to 8' though. Typically, repairs will need to extend 2x the distance of the damaged area, which would be 9' overall. You need an engineered letter stating the needed repairs for in the future if you sell the home and it comes up later.

I would also check with mettech, they make all kinds of things for TGI's but I don't imagine there is anything out there that allows for the cutting of the bottom chord, thats a big no no. I think their site is met-tech.com. They may be able to engineer the repair with photos instead of a site inspection by a local also, they have for me in the past.
SB