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Best way to repair notched joist (with pic)
I'm redoing my basement and came across a 2X8 joist that was notched
at some point in the past.It is notched approx It is the last joist before the outside sill plate. As you can see it is close to the steel beam. What is the best way to repair it or strengthen it? I was thinking put another piece of 2X8 next to it, one end resting on the beam and extending a good 2 feet past the notch, fastening it with bolts and washers. Any inputs appreciated. http://picasaweb.google.com/lh/photo...eat=directlink |
Best way to repair notched joist (with pic)
On Dec 30, 9:44*pm, Mikepier wrote:
I'm redoing my basement and came across a 2X8 joist that was notched at some point in the past.It is notched approx *It is the last joist before the outside sill plate. As you can see it *is close to the steel beam. What is the best way to repair it or strengthen it? I was thinking put another piece of 2X8 next to it, one end resting on the beam and extending a good 2 feet past the notch, fastening it with bolts and washers. Any inputs appreciated. http://picasaweb.google.com/lh/photo...XHVg?feat=dire.... Your idea seems ok, you might want to raise the existing joist on the side away from the steel I-beam about 1/4 inch before connecting the parallel plate/joist as it will have a certain amount of "give"and by raising the existing joist, putting the plate in and then removing the raiser mechanism, the new pkate will have part of the load. Yoiu could raise the existing joist using a jackpost or even a 2x4 shoved under the joist at an angle and then moving the 2x4 to a more vertical position by hammering it toward vertical. A string and weight next to a ruler or even just a ruler can tell you when the existing joist is raised up the 1/4 inch. |
Best way to repair notched joist (with pic)
On Dec 31, 4:11*am, zxcvbob wrote:
hr(bob) wrote: On Dec 30, 9:44 pm, Mikepier wrote: I'm redoing my basement and came across a 2X8 joist that was notched at some point in the past.It is notched approx *It is the last joist before the outside sill plate. As you can see it *is close to the steel beam. What is the best way to repair it or strengthen it? I was thinking put another piece of 2X8 next to it, one end resting on the beam and extending a good 2 feet past the notch, fastening it with bolts and washers. Any inputs appreciated. http://picasaweb.google.com/lh/photo...XHVg?feat=dire.... Your idea seems ok, you might want to raise the existing joist on the side away from the steel I-beam about 1/4 inch before connecting the parallel plate/joist as it will have a certain amount of "give"and by raising the existing joist, putting the plate in and then removing the raiser mechanism, the new pkate will have part of the load. *Yoiu could raise the existing joist using a jackpost or even a 2x4 shoved under the joist at an angle and then moving the 2x4 to a more vertical position by hammering it toward vertical. *A string and weight next to a ruler or even just a ruler can tell you when the existing joist is raised up the 1/4 inch. If you have a floor jack in your garage, you can use it and a 2x4 to take the load off the existing joist before you sister it. I fixed a broken rafter that way once in a poorly-built shed. *Had to jack up not only the broken rafter but the ones next to it to get the roof nice and even again. Use nails and glue instead of bolts. *A bolt thru a hole will have too much play even when you tighten it. -Bob Bob- Hide quoted text - - Show quoted text - Or timber connecters on the bolts between the joist and your bolt on piece. Such as these. http://www.tecoproducts.co.uk/TimberConnectors.htm Good idea to jack the joist up before tightening. Hugely enhances the joint strength. |
Best way to repair notched joist (with pic)
On Dec 30, 10:44*pm, Mikepier wrote:
I'm redoing my basement and came across a 2X8 joist that was notched at some point in the past.It is notched approx *It is the last joist before the outside sill plate. As you can see it *is close to the steel beam. What is the best way to repair it or strengthen it? I was thinking put another piece of 2X8 next to it, one end resting on the beam and extending a good 2 feet past the notch, fastening it with bolts and washers. Any inputs appreciated. http://picasaweb.google.com/lh/photo...XHVg?feat=dire.... If you can.... Plan A---- run another joist the entire length and rest it on both ends at the same point the existing joist is resting. Basically you're replacing the existing joists load. Plan B --- I would get a metal plate cut and drilled to span the gap, then bolt it to the existing joist. Plan C ---- What you want to do. :-) Caution... If you jack up the joist, be sure to check the floor above to see of any raising of the floor will effect anything. Sometimes raising only a fraction of an inch can make doors "out of plumb", therefore affecting their operation. Hank |
Best way to repair notched joist (with pic)
"Mikepier" wrote in message ... I'm redoing my basement and came across a 2X8 joist that was notched at some point in the past.It is notched approx It is the last joist before the outside sill plate. As you can see it is close to the steel beam. What is the best way to repair it or strengthen it? I was thinking put another piece of 2X8 next to it, one end resting on the beam and extending a good 2 feet past the notch, fastening it with bolts and washers. Any inputs appreciated. http://picasaweb.google.com/lh/photo...eat=directlink That sure is a scary picture. Just to make you think. How long has it been that way? What problems has it caused? For what reason was it cut? Do you really need to do anything? Colbyt |
Best way to repair notched joist (with pic)
On Dec 30, 10:44*pm, Mikepier wrote:
I'm redoing my basement and came across a 2X8 joist that was notched at some point in the past.It is notched approx *It is the last joist before the outside sill plate. As you can see it *is close to the steel beam. What is the best way to repair it or strengthen it? I was thinking put another piece of 2X8 next to it, one end resting on the beam and extending a good 2 feet past the notch, fastening it with bolts and washers. Any inputs appreciated. http://picasaweb.google.com/lh/photo...XHVg?feat=dire.... I would move. You have far too many different colored objects in that area for any repair of the joist to be effective. |
Best way to repair notched joist (with pic)
On Dec 31, 7:19*am, Hank wrote:
On Dec 30, 10:44*pm, Mikepier wrote: I'm redoing my basement and came across a 2X8 joist that was notched at some point in the past.It is notched approx *It is the last joist before the outside sill plate. As you can see it *is close to the steel beam. What is the best way to repair it or strengthen it? I was thinking put another piece of 2X8 next to it, one end resting on the beam and extending a good 2 feet past the notch, fastening it with bolts and washers. Any inputs appreciated. http://picasaweb.google.com/lh/photo...XHVg?feat=dire.... If you can.... Plan A---- run another joist the entire length and rest it on both ends at the same point the existing joist is resting. Basically you're replacing the existing joists load. Plan B --- I would get a metal plate cut and drilled to span the gap, then bolt it to the existing joist. Plan C ---- What you want to do. :-) Caution... If you jack up the joist, be sure to check the floor above to see of any raising of the floor will effect anything. Sometimes raising only a fraction of an inch can make doors "out of plumb", therefore affecting their operation. Hank I have my kitchen floor above with ceramic tiles. Thats my only concern about jacking up the joist with tiles cracking, getting loose. I can't run another full length joist, too many obstructions. Rather than use bolts, can I use lag screws? |
Best way to repair notched joist (with pic)
That sure is a scary picture. Just to make you think. How long has it been that way? At least 30 years. What problems has it caused? None that I'm aware of For what reason was it cut? It was notched for a 2" PVC pipe that went outside to the sprinkler system. Below the picture used to be a pump with a pipe going in the ground. Do you really need to do anything? I don't know. I figured now I had the walls opened, I would try to at least do something. |
Best way to repair notched joist (with pic)
On Fri, 31 Dec 2010 02:12:34 -0800 (PST), harry
wrote: On Dec 31, 4:11Â*am, zxcvbob wrote: hr(bob) wrote: On Dec 30, 9:44 pm, Mikepier wrote: I'm redoing my basement and came across a 2X8 joist that was notched at some point in the past.It is notched approx Â*It is the last joist before the outside sill plate. As you can see it Â*is close to the steel beam. What is the best way to repair it or strengthen it? I was thinking put another piece of 2X8 next to it, one end resting on the beam and extending a good 2 feet past the notch, fastening it with bolts and washers. Any inputs appreciated. http://picasaweb.google.com/lh/photo...XHVg?feat=dire... Your idea seems ok, you might want to raise the existing joist on the side away from the steel I-beam about 1/4 inch before connecting the parallel plate/joist as it will have a certain amount of "give"and by raising the existing joist, putting the plate in and then removing the raiser mechanism, the new pkate will have part of the load. Â*Yoiu could raise the existing joist using a jackpost or even a 2x4 shoved under the joist at an angle and then moving the 2x4 to a more vertical position by hammering it toward vertical. Â*A string and weight next to a ruler or even just a ruler can tell you when the existing joist is raised up the 1/4 inch. If you have a floor jack in your garage, you can use it and a 2x4 to take the load off the existing joist before you sister it. I fixed a broken rafter that way once in a poorly-built shed. Â*Had to jack up not only the broken rafter but the ones next to it to get the roof nice and even again. Use nails and glue instead of bolts. Â*A bolt thru a hole will have too much play even when you tighten it. -Bob Bob- Hide quoted text - - Show quoted text - Or timber connecters on the bolts between the joist and your bolt on piece. Such as these. http://www.tecoproducts.co.uk/TimberConnectors.htm Good idea to jack the joist up before tightening. Hugely enhances the joint strength. Almost as effective, and a lot less work, is to lay a 2X4 under the joist, well slathered with glue, and using a 4X4 on a jack, or a jackpost (I would NEVER use a 2X4 on end for that kind of jacking). jack the joist up so it is inline with the rest of the joists and spike the 2X4 to the bottom with a row of spikes, spaced about 6" apart. You would be building a "spar" or "truss" as strong as the original beam by using the 2X4 as a "spar cap" in tension. Whoever did that notch sure didn't have any concept of what they were doing!!! |
Best way to repair notched joist (with pic)
On Dec 31, 11:39*am, Mikepier wrote:
On Dec 31, 7:19*am, Hank wrote: On Dec 30, 10:44*pm, Mikepier wrote: I'm redoing my basement and came across a 2X8 joist that was notched at some point in the past.It is notched approx *It is the last joist before the outside sill plate. As you can see it *is close to the steel beam. What is the best way to repair it or strengthen it? I was thinking put another piece of 2X8 next to it, one end resting on the beam and extending a good 2 feet past the notch, fastening it with bolts and washers. Any inputs appreciated. http://picasaweb.google.com/lh/photo...XHVg?feat=dire... If you can.... Plan A---- run another joist the entire length and rest it on both ends at the same point the existing joist is resting. Basically you're replacing the existing joists load. Plan B --- I would get a metal plate cut and drilled to span the gap, then bolt it to the existing joist. Plan C ---- What you want to do. :-) Caution... If you jack up the joist, be sure to check the floor above to see of any raising of the floor will effect anything. Sometimes raising only a fraction of an inch can make doors "out of plumb", therefore affecting their operation. Hank I have my kitchen floor above with ceramic tiles. Thats my only concern about jacking up the joist with tiles cracking, getting loose. I can't run another full length joist, too many obstructions. Rather than use bolts, can I use lag screws?- Hide quoted text - - Show quoted text - I don't see why lag screws wouldn't work, just make sure you pre-drill the correct size hole. I lagged some "modern-day" 2 x 4's to the 50 YO 2 x 4 studs in my garage for shelving. New wood to new wood was a breeze but I snapped the heads off a couple of lags using the same sized hole in the older wood. It was much, much harder and required a slightly larger hole. I would also make sure there were some threads in both pieces of wood. I don't think that you would want all smooth shaft in either piece as the threads would hold everything in place better. |
Best way to repair notched joist (with pic)
On Fri, 31 Dec 2010 08:49:57 -0800 (PST), Mikepier
wrote: That sure is a scary picture. Just to make you think. How long has it been that way? At least 30 years. What problems has it caused? None that I'm aware of For what reason was it cut? It was notched for a 2" PVC pipe that went outside to the sprinkler system. Below the picture used to be a pump with a pipe going in the ground. Do you really need to do anything? I don't know. I figured now I had the walls opened, I would try to at least do something. You say you have the walls opened. If this is in a wall, simply support it on both sides with studs. If it hasn't gone anywhere in 30 years, it's unlikely to now. However, I'd do something about it too. |
Best way to repair notched joist (with pic)
On Dec 30, 10:44*pm, Mikepier wrote:
As you can see it *is close to the steel beam. By this, do you mean that the gray object slightly closer to the camera than the notched beam is a structural steel beam? If it's a full length beam that the flooring above sits on, then I'm not sure the wood beam is worth worrying about. I would ask for other opinions after answering that question though. I'm no engineer. |
Best way to repair notched joist (with pic)
wrote:
On Fri, 31 Dec 2010 02:12:34 -0800 (PST), harry wrote: On Dec 31, 4:11 am, zxcvbob wrote: hr(bob) wrote: On Dec 30, 9:44 pm, Mikepier wrote: I'm redoing my basement and came across a 2X8 joist that was notched at some point in the past.It is notched approx It is the last joist before the outside sill plate. As you can see it is close to the steel beam. What is the best way to repair it or strengthen it? I was thinking put another piece of 2X8 next to it, one end resting on the beam and extending a good 2 feet past the notch, fastening it with bolts and washers. Any inputs appreciated. http://picasaweb.google.com/lh/photo...XHVg?feat=dire... Your idea seems ok, you might want to raise the existing joist on the side away from the steel I-beam about 1/4 inch before connecting the parallel plate/joist as it will have a certain amount of "give"and by raising the existing joist, putting the plate in and then removing the raiser mechanism, the new pkate will have part of the load. Yoiu could raise the existing joist using a jackpost or even a 2x4 shoved under the joist at an angle and then moving the 2x4 to a more vertical position by hammering it toward vertical. A string and weight next to a ruler or even just a ruler can tell you when the existing joist is raised up the 1/4 inch. If you have a floor jack in your garage, you can use it and a 2x4 to take the load off the existing joist before you sister it. I fixed a broken rafter that way once in a poorly-built shed. Had to jack up not only the broken rafter but the ones next to it to get the roof nice and even again. Use nails and glue instead of bolts. A bolt thru a hole will have too much play even when you tighten it. -Bob Bob- Hide quoted text - - Show quoted text - Or timber connecters on the bolts between the joist and your bolt on piece. Such as these. http://www.tecoproducts.co.uk/TimberConnectors.htm Good idea to jack the joist up before tightening. Hugely enhances the joint strength. Almost as effective, and a lot less work, is to lay a 2X4 under the joist, well slathered with glue, and using a 4X4 on a jack, or a jackpost (I would NEVER use a 2X4 on end for that kind of jacking). jack the joist up so it is inline with the rest of the joists and spike the 2X4 to the bottom with a row of spikes, spaced about 6" apart. You would be building a "spar" or "truss" as strong as the original beam by using the 2X4 as a "spar cap" in tension. Whoever did that notch sure didn't have any concept of what they were doing!!! Or use a piece of 1/4" steel flat bar to close up the bottom. Put some tension on the steel if you can. But even without tension, it would hold the joist together if it ever decides to break. And most importantly, it would *look* a lot safer than what you have now :-) -Bob |
Best way to repair notched joist (with pic)
Mikepier wrote:
Plan A---- run another joist the entire length and rest it on both ends at the same point the existing joist is resting. Basically you're replacing the existing joists load. Plan B --- I would get a metal plate cut and drilled to span the gap, then bolt it to the existing joist. Plan C ---- What you want to do. :-) Caution... If you jack up the joist, be sure to check the floor above to see of any raising of the floor will effect anything. Sometimes raising only a fraction of an inch can make doors "out of plumb", therefore affecting their operation. Hank I have my kitchen floor above with ceramic tiles. Thats my only concern about jacking up the joist with tiles cracking, getting loose. I can't run another full length joist, too many obstructions. Rather than use bolts, can I use lag screws? Lag screws would be better than bolts. Bolts have a small, but significant, wobble-factor. Don't forget to slather the sucker with about a quart of glue. Maybe some strapping... |
Best way to repair notched joist (with pic)
Whatever technique you use for attaching, scab or sister that joist on
both sides, not just one side. Sonny |
Best way to repair notched joist (with pic)
On Dec 31, 12:33*pm, Sonny wrote:
Whatever technique you use for attaching, scab or sister that joist on both sides, not just one side. Sonny Why? |
Best way to repair notched joist (with pic)
On Dec 31, 11:39*am, Mikepier wrote:
If you can.... Plan A---- run another joist the entire length and rest it on both ends at the same point the existing joist is resting. Basically you're replacing the existing joists load. Plan B --- I would get a metal plate cut and drilled to span the gap, then bolt it to the existing joist. Plan C ---- What you want to do. :-) Caution... If you jack up the joist, be sure to check the floor above to see of any raising of the floor will effect anything. Sometimes raising only a fraction of an inch can make doors "out of plumb", therefore affecting their operation. Hank I have my kitchen floor above with ceramic tiles. Thats my only concern about jacking up the joist with tiles cracking, getting loose. I can't run another full length joist, too many obstructions. Rather than use bolts, can I use lag screws?- Whatever you do will be better than what you have. Screws should be ok. Put constrcution adhesive between the boards. Hank |
Best way to repair notched joist (with pic)
On Dec 30, 10:44*pm, Mikepier wrote:
One more thing..... If you can sandwich a piece of plywood ( the thicker the better, the longer the better) between the 2 boards with adhesive, that will fix your problem for sure. Hank |
Best way to repair notched joist (with pic)
When you say adhesive, is liquid nails good?
|
Best way to repair notched joist (with pic)
On Dec 31, 12:09*pm, Larry Fishel wrote:
On Dec 30, 10:44*pm, Mikepier wrote: As you can see it *is close to the steel beam. By this, do you mean that the gray object slightly closer to the camera than the notched beam is a structural steel beam? If it's a full length beam that the flooring above sits on, then I'm not sure the wood beam is worth worrying about. I would ask for other opinions after answering that question though. I'm no engineer. Yes that is a steel beam spanning the center of the basement with joists running perpendicular. |
Best way to repair notched joist (with pic)
On Dec 31, 1:11*pm, Mikepier wrote:
On Dec 31, 12:09*pm, Larry Fishel wrote: On Dec 30, 10:44*pm, Mikepier wrote: As you can see it *is close to the steel beam. By this, do you mean that the gray object slightly closer to the camera than the notched beam is a structural steel beam? If it's a full length beam that the flooring above sits on, then I'm not sure the wood beam is worth worrying about. I would ask for other opinions after answering that question though. I'm no engineer. Yes that is a steel beam spanning the center of the basement with joists running perpendicular. I'm confused. Is the "beam" you are referring to in the lower left of the picture right above the yellow romex that loops to bottom of the picture? If so, why does it look like wood? It looks like it's a piece of wood with possibly a steel plate attached to the face of it. Not that that has anything to do with the repair of the joist. It's just that it doesn't look like a "beam", at least not to me. Am I missing something? |
Best way to repair notched joist (with pic)
On Dec 31, 12:29*pm, "HeyBub" wrote:
Mikepier wrote: Rather than use bolts, can I use lag screws? Lag screws would be better than bolts. Bolts have a small, but significant, wobble-factor. At a maximum inch and a half embedded the lag would not be nearly as strong as a bolt through a correctly sized hole. Not even remotely. R |
Best way to repair notched joist (with pic)
On Dec 31, 1:07*pm, Mikepier wrote:
When you say adhesive, is liquid nails good? Any polyurethane construction adhesive would do. R |
Best way to repair notched joist (with pic)
On Dec 31, 11:52*am, wrote:
Whoever did that notch sure didn't have any concept of what they were doing!!! They knew exactly what they were doing. They knew they didn't give a damn and wanted to be finished as quickly as possible. R |
Best way to repair notched joist (with pic)
On Dec 31, 1:23*pm, RicodJour wrote:
On Dec 31, 12:29*pm, "HeyBub" wrote: Mikepier wrote: Rather than use bolts, can I use lag screws? Lag screws would be better than bolts. Bolts have a small, but significant, wobble-factor. At a maximum inch and a half embedded the lag would not be nearly as strong as a bolt through a correctly sized hole. *Not even remotely. R But in this case would it matter? Serious question, I'm no structural engineer. With a 2 x 8 sistered across the notch, extending let's say 2 feet on each side, and then glued and lagged in, let's say, 4 (6?) places on both sides of the notch wouldn't that be more than enough to fix the current problem? Would bolts really add anything worth considering or would they amount to overkill? Of course, that's not to say that bolts wouldn't actually be easier to install. |
Best way to repair notched joist (with pic)
I'm confused.
Is the "beam" you are referring to in the lower left of the picture right above the yellow romex that loops to bottom of the picture? If so, why does it look like wood? It looks like it's a piece of wood with possibly a steel plate attached to the face of it. Not that that has anything to do with the repair of the joist. It's just that it doesn't look like a "beam", at least not to me. Am I missing something? There is a 2X4 resting flat on top of the I-beam that runs the whole length. |
Best way to repair notched joist (with pic)
On Dec 31, 1:40*pm, Mikepier wrote:
I'm confused. Is the "beam" you are referring to in the lower left of the picture right above the yellow romex that loops to bottom of the picture? If so, why does it look like wood? It looks like it's a piece of wood with possibly a steel plate attached to the face of it. Not that that has anything to do with the repair of the joist. It's just that it doesn't look like a "beam", at least not to me. Am I missing something? There is a 2X4 resting flat on top of the I-beam that runs the whole length. Oh...I see it now. It's an I-beam and that bundle of wires runs under the top horizontal. I didn't notice the rust on the vertical part until just now. Thanks! I wonder why they used a 2 x 4 on top of it. Just seems like something that could crush of a joist was positioned on a soft spot. In my house they set the ends of the beam in a bed of concrete to get it to a height where the joists rest right on the beam. |
Best way to repair notched joist (with pic)
On Dec 31, 12:23*pm, RicodJour wrote:
On Dec 31, 1:07*pm, Mikepier wrote: When you say adhesive, is liquid nails good? Any polyurethane construction adhesive would do. R A two part epoxy is even better. Sister the joist on both sides with 3/4" plywood of substantial length and the lost strength should be totally recovered. Joe |
Best way to repair notched joist (with pic)
On 12/31/2010 9:20 AM, Colbyt wrote:
wrote in message ... I'm redoing my basement and came across a 2X8 joist that was notched at some point in the past.It is notched approx It is the last joist before the outside sill plate. As you can see it is close to the steel beam. What is the best way to repair it or strengthen it? I was thinking put another piece of 2X8 next to it, one end resting on the beam and extending a good 2 feet past the notch, fastening it with bolts and washers. Any inputs appreciated. http://picasaweb.google.com/lh/photo...eat=directlink That sure is a scary picture. Just to make you think. How long has it been that way? What problems has it caused? For what reason was it cut? Do you really need to do anything? Colbyt That close to center beam, and to the fully-supported joist on outside wall, unlikely to fail catastrophically. But just on general principles, I'd sister it anyway. From over the beam to maybe 18-24 inches past the notch. A couple 16s to baste it in place, then some staggered carriage bolts on each end. If that isn't possible, then a 2x4 or steel strap lagged into the bottom of the joist to take the stress off of the cut section. Unless a 4-foot level on the floor upstairs shows any sag, I wouldn't even bother to jack it. Hard to say what it was for, without inspecting the space for other clues, like on the outside wall. Maybe a long-gone oil fill line? I've seen worse, in more critical locations. Held fine for years, then one day somebody walks through carrying a piano, and 'crack'. Carpenters have long been of the opinion that plumbers and electricians should be prohibited by law from owning sawzalls. -- aem sends... |
Best way to repair notched joist (with pic)
On Dec 31, 1:07*pm, Mikepier wrote:
When you say adhesive, is liquid nails good? Yes, that'll work. Don't be shy with it. Hank |
Best way to repair notched joist (with pic)
wrote in message ... On Fri, 31 Dec 2010 08:49:57 -0800 (PST), Mikepier wrote: That sure is a scary picture. Just to make you think. How long has it been that way? At least 30 years. What problems has it caused? None that I'm aware of For what reason was it cut? It was notched for a 2" PVC pipe that went outside to the sprinkler system. Below the picture used to be a pump with a pipe going in the ground. Do you really need to do anything? I don't know. I figured now I had the walls opened, I would try to at least do something. You say you have the walls opened. If this is in a wall, simply support it on both sides with studs. If it hasn't gone anywhere in 30 years, it's unlikely to now. However, I'd do something about it too. For Mike, After 30 years it has done all it is likely to do, but I agree with both you, I would scab it on each side if possible extending 18-24" past the notch. Thereafter I would forget about it. -- Colbyt Please come visit http://www.househomerepair.com |
Best way to repair notched joist (with pic)
On Fri, 31 Dec 2010 09:43:09 -0800 (PST), DerbyDad03
wrote: On Dec 31, 12:33*pm, Sonny wrote: Whatever technique you use for attaching, scab or sister that joist on both sides, not just one side. Sonny Why? It won't twist. |
Best way to repair notched joist (with pic)
On Dec 31, 7:17*pm, "
wrote: On Fri, 31 Dec 2010 09:43:09 -0800 (PST), DerbyDad03 wrote: On Dec 31, 12:33*pm, Sonny wrote: Whatever technique you use for attaching, scab or sister that joist on both sides, not just one side. Sonny Why? It won't twist. So I guess the assumption is that a new piece of 2 x 8, glued and screwed/lagged/bolted to one side would have enough strength to twist the existing joist if it should twist as it aged? I can see that, especially with the notch cut out. How about if 2 layers of 3/4" ply were glued up and used on one side? That wouldn't twist would it? Would that be stronger than a single piece of 3/4" on each side? Just curious, that's all. If 2 layers of 3/4" ply were used as the sister, glued and screwed |
Best way to repair notched joist (with pic)
On Dec 31, 6:13*pm, DerbyDad03 wrote:
On Dec 31, 7:17*pm, " wrote: On Fri, 31 Dec 2010 09:43:09 -0800 (PST), DerbyDad03 wrote: On Dec 31, 12:33*pm, Sonny wrote: Whatever technique you use for attaching, scab or sister that joist on both sides, not just one side. Sonny Why? It won't twist. So I guess the assumption is that a new piece of 2 x 8, glued and screwed/lagged/bolted to one side would have enough strength to twist the existing joist if it should twist as it aged? I can see that, especially with the notch cut out. How about if 2 layers of 3/4" ply were glued up and used on one side? That wouldn't twist would it? Would that be stronger than a single piece of 3/4" on each side? Just curious, that's all. If 2 layers of 3/4" ply were used as the sister, glued and screwed Why sister both sides? (ideally) It's a symmetry thing. The original un-notched beam was symmetric with respect to the vertical load it carried. Sistering only one side creates a non-symmetric joist. Probably a minor / second order effect but symmetry is ideal. Adding 3/4" plywood to both sides of the joist restores symmetry to the system. The chief engineer I worked with for nearly ten years taught me "God likes symmetry". To repair the joist I would jack the notched beam slightly (to sister a member without relieving the load by jacking leaves the sister unloaded by the existing load). I would cut two sisters from 3/4" plywood, glue and mechanically fasten in place. As per other posts, the plywood should extend at least 18" beyond notch. My choices of fasteners would be. 1) Senco M2 style staples; 2" o/c all directions, both sisters. 2) .148" dia plywood shorts; 3" o/c 3) Simpson SDS 1/4; 4" o/c To get the sisters to take load you have to transfer shear from the notched beam to the sisters. That means jacking & good tight fastening (glue & staples, nails or lags). Bolts are typically installed with over sized holes, not the best way to transfer shear. Keep the jack in place until the glue dries. cheers Bob |
Best way to repair notched joist (with pic)
My choices of fasteners would be. 1) Senco M2 style staples; 2" o/c all directions, both sisters. 2) .148" dia plywood shorts; 3" o/c 3) Simpson SDS 1/4; 4" o/c What is number 2? |
Best way to repair notched joist (with pic)
On Fri, 31 Dec 2010 18:13:42 -0800 (PST), DerbyDad03
wrote: On Dec 31, 7:17*pm, " wrote: On Fri, 31 Dec 2010 09:43:09 -0800 (PST), DerbyDad03 wrote: On Dec 31, 12:33*pm, Sonny wrote: Whatever technique you use for attaching, scab or sister that joist on both sides, not just one side. Sonny Why? It won't twist. So I guess the assumption is that a new piece of 2 x 8, glued and screwed/lagged/bolted to one side would have enough strength to twist the existing joist if it should twist as it aged? I can see that, especially with the notch cut out. How about if 2 layers of 3/4" ply were glued up and used on one side? That wouldn't twist would it? Would that be stronger than a single piece of 3/4" on each side? I'm not a structural engineer, but I'd say no. Symmetry is your friend. Just curious, that's all. If 2 layers of 3/4" ply were used as the sister, glued and screwed I don't believe two layers is twice as strong as one (fasteners, glue joint, etc.) Opposite sides would have twice the fasteners and glue. ...though I don't think the fasteners do much here. |
Best way to repair notched joist (with pic)
On Dec 31 2010, 1:11*pm, Mikepier wrote:
On Dec 31, 12:09*pm, Larry Fishel wrote: On Dec 30, 10:44*pm, Mikepier wrote: As you can see it *is close to the steel beam. By this, do you mean that the gray object slightly closer to the camera than the notched beam is a structural steel beam? If it's a full length beam that the flooring above sits on, then I'm not sure the wood beam is worth worrying about. I would ask for other opinions after answering that question though. I'm no engineer. Yes that is a steel beam spanning the center of the basement with joists running perpendicular. I should have been more clear. I meant the gray object at the top of the photo that seems to be running parallel to the notched beam. |
Best way to repair notched joist (with pic)
I should have been more clear. I meant the gray object at the top of
the photo that seems to be running parallel to the notched beam. HVAC duct running inside the joists |
Best way to repair notched joist (with pic)
On Dec 31 2010, 11:43*am, DerbyDad03 wrote:
On Dec 31, 12:33*pm, Sonny wrote: Whatever technique you use for attaching, scab or sister that joist on both sides, not just one side. Sonny Why? Maximum strength. |
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