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Thor. I think I can picture the situation.
If I am understanding it correctly the flitch plate beam would work well in this situation. You could leave the existing rim joist where it is, using it as part of the flitch beam and just build off of the side of it with successive layers of steel and 2×10’s as per engineers specifications. Temporarily support the floor joists while you remove the existing bearing wall. Once the wall is removed you can install standard joist hangers onto the original rim joist. That should take care of the floor load.
The next issue is the trusses. Trusses are specifically designed for each and every situation. For this reason you wont find any information on standard methods of how to modify a roof truss, there’s just to many variables. However that being said I have run into a similar situation in the past with higher live loads than you are dealing with. The idea you mentioned using plywood to gusset the sides of the truss is what we were directed to do by the truss company. Therefor my suggestion would be to contact a truss company and talk to their engineer. They usually understand the dynamics of truss design better than general structural engineers because that’s all they do every day.
I hope these suggestions help, Good luck.
Replies
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Just finished re-doing my kitchen on first floor of 2 story house. Needed to remove bearing wall and replaced with a w8X21 steel beam 14'- 9" end to end. Mounted 2X8's double stacked both sides to carry 2nd floor joists. Beam was perpendicular to floor/celing joists. Through bolted the sandwiched 2X8's with 3/4" bolts and gave steel company bolt hole locations based on centering them in the joist spaces. Offset pattern to the bolt locations with 1 high 1 low thru the beam. Simpson hangers used to hang the joists. The joists had to be cut exact and the beam actually drug on the joists as we lifted it. Simpson hangers require less that 3/8" total separation between joist end and beam. Must be exact as possible. Simpson hangers had to be spec'd for the load also. This beam was small enough we muscled it into place stair step like, as one other poster said. We built up under it with scabs on the end walls and cribbing on the free end until we could slide it back into the pocket we made to the outer band beams. Used hydraulic jacks to get up into final position because of drag on the joists. Actually had to have helpers go up to 2nd floor and jump up and down to load the beam fully. Used shim stock to check that 2nd floor was all the way down onto top of beam after we pulled the outer jackposts that held the 2nd floor up during demo work. Because we have bedrooms over this space and no snow load (SC) to consider, the structural engineer used 100 pounds per square foot as design load. Furred out the underside of the joist with 2X2 to hang sheetrock and clear the deeper beam. Worked good and we are very pleased.
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Matt - Bearing on the flange of an I-beam is a structural no-no. Bearing should be on the web via bolted-on nailer and joist hangers.
Jeff Clarke
*RED FLAG!!!!!! Thor, Ijust thought I would throw something in. I worked on a similar project several years ago. We bolted nailers to either side of an I-beam using 1/2" carriage bolts, I don't recall if it was 16" or 24" centers. (Ok, so it was maybe a little bit more than "several" years ago...) Anyhoo, back to the point... All those bolts buckled and the nailerboards sank until they came to rest on the bottom flange!!! As I recall, it was a 12" beam and the nailers were 2X10 so the sag was fairly substantial. The really fun part about the whole thing, as you might expect, was that it wasn't noticed until well into the trim stage of the project. "Oh what a joy that whole project was from that point on" Anyway, You seem to have gotten a plethora of sound advice and information here, there seems to be a growing number of really talented and knowledgeable carpenters sitting in front of a keyboard these days. One last note, I have gone down to the local rental place and rented a winch type jack (uses steel cables, pulleys, and a crank,) and used it to lift some pretty hefty beams into place. Good luck!
*Although the attached drawing is a little rough maybe the idea would be helpful. Rather than depend on the integrity of bolts thru the web or worry about the compressibility of the wood spacers or the sag as one poster mentioned or buying Simpson - fabricate and weld brackets to accomodate joist ends. 1/4 inch plate, bent or welded in a U shape, with bottom bearing surface, is equal to or better than anything Simpson has to offer, IMHO. And, it's a single process rather than a build-up. Just measure carefully.Comments? Ralph
*Mark: I agree with the possibility of sagging nailer or even shearing off bolts. The Blue Eyed Devil had suggested welding a plate across the bottom flange to pickup the load. Any nailer would have already been in contact with that plate. Of course plates could also be welded above the lower plate to fabricate a flat horizontal surface to pickup any load from bolted nailers....just more work on the part of the fabricator and welder. I'll be checking on that rental winch-type jack.Bill: Sounds very much like what I have to do. If I read your post right I got the impression that you attached the hangers to the nailer and then lifted the whole thing into place. Were these regular joist hangers like a U210? Didn't you have a rim joist on the second floor and the second floor wall built on top of that rim joist? If you pulled the rim joist, and used the U210's, couldn't you have attached the hangers AFTER the beam was in place. Maybe you used a specialty hanger? My engineer doesn't want to pull the rim joist and the beam will be parallel to it. I don't know yet how he will pick up that side load.Ralph: Ah, a genuine lover of metal crafting. Fantastic drawing. Great way to describe things. I wish I could "zoom out" with Netscape to view the whole drawing. Pretty labor intensive to cut those 1/4" pieces to fit the inside of the beam profile. Been there and done that. Everything better line up because there won't be any changes. I don't think 1/4" is needed to prevent joist rotation with a glued and nailed subfloor but....love the drawing...we need more of that here....how did you make it and how long did it take?To All Posters: I have really gained from this exchange. I gave the engineer this address and told him to take a look. Don't know if he did. The latest is that a MacMillan Parallam PSL (Parallel Strand Lumber) will be used. 7" X 18". Pimary concerns being the torsion on the beam caused by the side loading from the 2nd floor joists.These joists come in a varity of widths so that they can be stacked (say one 3 1/2" with a 1 3/4" on either side) to reach the same design property of a single beam and thus break up the weight into 3 easier to handle lifts. HOWEVER, due to the side loading/torsion concerns the engineer wants a ONE PIECE beam. That is 39.4 lbs per foot or about 700 lbs. Information given to me is that torsion is better controlled with a Parallam (or similar) than the steel I-beam approach regardless of how a nailer is attached. Check with your engineer or let me know if any one has any good/bad comments on Parallam. Thanks Again.....Thor
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New client. Wants to enclose patio just outside kitchen and then remove the old exterior kitchen load bearing wall. Beam has to be recessed into ceiling to make the ceiling of newly enclosed patio and kitchen one continuous plane. Engineer is mulling over size of beam (about an 18' clear span with about half of that supporting the second floor). He started talking glulam, micro lam, etc. but now is considering steel. The beam will run parallel with the 2nd floor rim joist and we will need to join existing 2X10's to the side of the beam. Is there a preferred method of attaching a wood nailer to the I-Beam? Will need wood on both sides. Any prohibition on holes in the web of the beam (or anywhere else?). I also weld. I suppose a nailer could be fitted to beam and held in place with steel tabs or straps. That nailer is going to have to pickup a fair load on the portion with the 2nd story may be some beam rotation to be concerned with. Size of beam not known yet. Any ideas? Thanks Thor
(Meanwhile I'll look for the special wood welding rod my Pappy always talked about.... hard to start an arc but when it goes.....poof!)
BTW...how do you accept/reject one of the replacement word suggestions in the spell checker....I kept looking for an "ignore" box next to each suggestion????
*Thor - When we have retrofitted steel beams, we have used tw methods that have worked out well. You are ahead of the game because you already have an engineer who can spec the details for you. One method is to bolt nailers on the side of the beam, bringing them out far enough to clear the flange, and then using a 2 x 10 to nail joist hangers to. The engineer can give you a bolt pattern to work to. This only works if you have the space to get in there and nail up joist hangers. Incidentally, drilling holes in the web is not a problem, but be prepared to use up a few drill bits. Actually, it's best to drill the holes in the steel first. The bit has to be able to clear the metal shavings from the hole or they will burn out very quickly. Or, your steel fabricator can supply the beam with the holes drilled for a small fee.Another approach is to weld a metal lip on the bottom of the flange. In other words, take some 1/4" plate and weld a shelf that sticks out on one side from the bottom flange. This can then catch the ends of the floor joist when you put the beam in place. You still have to go back and figure a way to ensure that the ends of the floor joist can't twist or pull way from the beam.There are of course other ways. Simpson does make joist hangers designed to be welded onto a beam. But when I tried to get some they were expensive and difficult to get. There is also C-channel, which if your engineer can spec a piece strong enough, is easier to work with than an I-beam because it is flat on one side.As far as any twisting force that may be applied to the beam, its best to have the engineer figure it out, but using metal pipe columns and welding or bolting them to the beam is probably the strongest connection.
*Thor:Order your steel with holes predrilled through the web. Then you bolt up your 2x10 (or whatever) nailers to each side with ½" carriage bolts. The flange of the I beam will still be protruding beyond the nailers and will support the end of your 2x10 floor/ceiling joists. Joist hangers may be required too, as specified by the PE. The joists will have to be notched so that the ceiling will be nice and flat. Typically, in a situation like this, a 10" beam would be used - something like a W10x33.BTW - Spell checker? Only used the new BT spell checker one time....
*I've bolted 2x's using spacers right through the web as has already been said. I've never tried the hangers made to be welded to the beam but I've wondered if they might be easier if the fabrication was done on horses so that the hangers could just be slipped over the existing floor joists.your engineer will give you the bolting schedule so don't sweat that detail.
*Thanks for everyone's imput. Still haven't heard back from the engineer but will pass on the suggestions. Of course one of the reasons I needed this info was to get a jump on estimating the cost for the client so your ideas are most welcome.I believe that the beam and the "nailer" will probably have to be positioned parallel and up against the rim joist so various joist hanger configs may not be possible. I believe the engineer did not want to remove the rim joist as the 2nd story wall (cantilevered over the existing exterior bearing wall by about 18") is partially bearing on the rim. Typical platform framing. I will have some of the ceiling drywall removed and temp supports so I will have access to the underside of the 2 X 10 joists and the rim joist. I'm sure the engineer will figure how to transfer the load. I sure that the rim joist attached to a nailer on the beam won't cut it. (end nailed, and relying on shear strength of 16's....no way...this is changing from point loads on top of a bearing wall to side loading a beam the way I see it)One more interesting requirement. Trusses. About 3/5's of the 18' span consist of engineered trusses that make up the roof line along side the portion of the house that has a 2nd story. These trusses run all the way from the front of the house, form the ridge, and then run over the rear exterior bearing wall (the wall that needs to come out) AND continue out to form the patio cover. I know this is a little difficult to picture mentally.The new beam must do three things. It must be recessed into the ceiling (invisible), because part of the area has a second floor it must pick up that load at the end of the 2nd story floor joists (instead of under the joists) AND it must support three trusses at a point 18 to 24 inches out from where the trusses now rest on a bearing wall. If I haven't lost you yet read on. The trussed portion must also be supported with the beam being recessed into the ceiling (presently formed by the bottom chord). This means cutting the truss. Engineer says he is working on a way to gusset the truss (plywood sandwiching the truss) so that the load is transferred out 24" to the new beam. I remember reading articles about recessed flitch plate beams but so far have been unable to find anything about modifying an engineered truss. Anybody have info on that? My motto has always been to never cut a truss but this engineer has been around for quite a while and it may be possible. Maybe another truss specially engineered could be sistered to the existing. The load is far less than the portion that is 2nd story. We have a 30# snow load, 10# dead, no live load on this trussed portion. Maybe I'll try to get an electronic picture or drawing to post. Never done that here...anybody know how? Thanks Again, Thor (bypassing the spell checker.....3/15/00 0900 MST)
*Thor, if you save your electronic picture - or scanned in picture, as a .JPG file, we should be able to open it. Put the file name in the "enclosures" box.jim
*Having trouble visualizing an 18" cantilevered second floor sitting on the same load bearing wall as a roof truss... Sure you don't want to just slice the whole building off at the load bearing wall and rebuild with new construction?Wouldn't it be easier to leave the trusses as is, place the beam in the original load bearing position and re-joist the cantilever? IE Support the cantilever, the second floor, and the trusses. Rip out the rim joist, notch the second floor joists, cut back or remove entirely the cantilever joists and slide the beam in so the second floor joists are resting in the flange. Then notch and install new joists (again resting on the flange) to carry the cantilevered second floor.
*Thor. I think I can picture the situation.If I am understanding it correctly the flitch plate beam would work well in this situation. You could leave the existing rim joist where it is, using it as part of the flitch beam and just build off of the side of it with successive layers of steel and 2x10's as per engineers specifications. Temporarily support the floor joists while you remove the existing bearing wall. Once the wall is removed you can install standard joist hangers onto the original rim joist. That should take care of the floor load. The next issue is the trusses. Trusses are specifically designed for each and every situation. For this reason you wont find any information on standard methods of how to modify a roof truss, there's just to many variables. However that being said I have run into a similar situation in the past with higher live loads than you are dealing with. The idea you mentioned using plywood to gusset the sides of the truss is what we were directed to do by the truss company. Therefor my suggestion would be to contact a truss company and talk to their engineer. They usually understand the dynamics of truss design better than general structural engineers because that's all they do every day.I hope these suggestions help, Good luck.
*Scott: Whoa! The "easier" way would be to "rip" and "notch" and "remove".....I gotta get a better mental picture of this "easier" way. Better yet I need to post a sketch (maybe an Etch-a-Sketch). The existing patio roof is supported partially by the trusses that span the entire 1st floor and partially by a cut roof. As is typical the entire roof was just replaced. The idea is to not disturb the basic existing patio roof BUT the client does not want any kind of beam breaking up the ceiling plane from the kitchen to the addition. A portion of the second floor is built right to the edge of the cantilever which includes the rim joist. I will try to sketch something out and post it....I appreciate the ideas.Thor
*OK. Here is an attempt at a plan view of the existing house with kitchen on 1st floor, cantilevered 2nd floor, already covered porch (to be enclosed), and the trussed area. I had to zoom in to see the lines as solid...don't know how it will come out when I post it. It's a JPG file. Thor
*Sounds like a flitch plate situation to me but my advice is to be patient and wait for the engineer. If he can't spec a doable job, get a second opinion. Seems like your customer is a little too pusshy. That's ok if he pays the bills on time but when he's asking for the impossible he needs to realize that it just takes alittle bit longer to do! If you let him push you into doing something questionable or posting an estimate before all information is in it'll be your pocketbook and reputation on the line. Keep it professional and you'll; be able to sleep at night.
*Thor, we have often ran into similar situations. The builders will normally have a 1/4" x 11" plate welded on the bottom and extended out to catch the joists. It is quite common here.I actually worked at a structural steel supplier for three years prior to becoming a carpenter. I have personally welded hundreds of these plates. Most were only hanging off one side of the beam to support a dropped family room which were poplular in the 70's. Ocasionally, the plate would extend past both edges. It's really not that big of a deal, and it is done here all the time without engineering reports. The 18' span will require a heavy beam probably somewherein the 51# per foot range. The engineer should be able to tell you in five minutes.blue
*Good ideas. Just to clarify...Nobody is in big hurry. Many of my customers have waited a year for me to schedule their job. I'm slow but I like to see things done right...of course sometimes its hard to make any money that way. I made my post because sometimes it takes awhile for comments and my estimates are pretty complete...sometimes I forget stuff though. Like right now I'm thinking how I can get that 1/2 ton of beam in place. When I was welding on this stuff we had forklifts and gantry cranes. I guess I could tear up their back yard...better add that to my estimate list.I feel honored that after browsing this forum for about a year that I actually got a response from the famous "blue eyed devil" himself. I like the plate idea too...now where did I put that 7018 rod. Hmmm...according to my I beam book I'm looking at a standard I beam weighing 50# per ft with dimensions of at least 12" in depth and 5.477 in flange width. Would that mean that the 11" plate would extend out both sides of the flange about 2.75"? Just wondered about that rather unusual 11" dimension. Thor
*Blue:If you're resting the joists on the bottom web (or a plate nailed to the bottom web), are you notching the bottom of the joists to give you a flush ceiling?
*:50# per ft with dimensions of at least 12" in depth - thought it might come to that. Smoothing over a 10" depth beam only means dropping the ceiling 1/2" to flush the joists out. Dropping the ceiling 2 1/2" is going to be noticable. If I were the client, I'd rather have a beam break the ceiling, than have the ceiling dropped that much (just my opinion).How are you going to handle the beam? I'm in something of a similar pickle.
*Thanks for the chuckle Thor.Thor, I think I remeber using 7018 rod too! It's been a long time, but I remeber the stuff made me look like a pro welder! We used to weld 1" long tack welds about 12" apart. We stocked 1/4 x 9" and 1/4 by 11" plates. These plates were more often installed as flitch plates, sandwhiched between 2x12's and bolted. This arrangement precluded the widespread use of laminated beams, and Microlams. I suppose you could obtain a 12" plate too, and there is also heavier thicknesses available. The heaviest plate that I remeber fabficating for residential use was 3/8", or possibly 1/2". But that stuff is heavier than needed to carry joist.Ryan C, is concerned with the steel plate hanging down below the plane of the joist. This relatively miniscule deviation is probably smaller than the normal flucuations that occur between differently crowned joist, and is small enough to allow a good construction glue to "bridge", if no special provisions are made. But a re-modeling homeowner would burst an artery if you attempted to install the joist without notching. Since all of my installations have occurred in the lower deck, I have never really had to deal with it. Personally, I'd just float my own drywall over it, but professionally, I'd make provisions for "customer satisfaction".Take care Scott and Ryan if you do decide to "notch". Joist will tend to split, at the notch, and you will actually be doing the homeowner a dis-service if you do notch into the joist. A better way is to taper the joist end, thus leaving no 90 degree nothch that a split can start in. Sometimes, the 2.75" is just not enough bearing. There are several things that can "add" bearing. I have notched the joist onto the bottom flange of the beam, giving additional support to the joist. This is time consuming, but effective. I have also added a "header" inside the beam, shooting it to the web. I find this less desireable, due to the poor bearing that the Header has. The curved profile of the beam makes this arrangment less than desirable. Putting a spacer on the web, then adding a "header" or a "rim" joist is probably a better way. This will require joist hangers though and is also time consuming. Anyways, it works. The plate carrying arrangment is sound construction. It is done extensively to carry brick on commercial jobs, which require engineering.Don't ask me how to hoist these beasts. I usually use a crane. I once used a rented portable forklift (the homeowner supplied it for a change worder- we hoisted a huge laminated beam about 15' up) once. It worked fine. blue
*Scott: In my case the 12" steel beam mating up to 2 X 10 joists won't be a problem because the beam will go up parallel and outboard of the existing rim joist. The pitch of the existing roof has plenty of room to fully recess the beam. I am more concerned about the portion of the roof made up of the trusses. While there is room to recess the beam I don't know yet how the engineer is going to workout the load transfer....just waiting.As far as handling the beam is concerned I haven't entirely worked that out. Initially I was going to have power equipment in the back to excavate for footings. Now, due to some rather unique landscaping, the plan is to hand dig. I recall seeing an article (haven't found it in my library yet and my JLC CD doesn't have it so....) where a flitch beam was placed by a lot of bodies. I think they staged it so each end was raised a short distance (like stairstepping it) until it was close to the beam pockets and everyone muscled it into place. I have moved 600# beams in the past but never had to go overhead, they were 25' long. I may have to tear up the landscaping just to get the beam around back but then I still have to get it over the new footing wall, under the porch roof and then, ugh, up into the ceiling. Maybe crane time. Drop the beam over the house, muscle it under the roof then remove part of the existing roof, drop a cable through and use the crane to lift it into place. What is your situation?Ryan: If I understood Blue correctly the joists would be resting on a steel plate welded to the bottom flange to, in effect, extend that flange (make the profile of the beam to look more like an upside down capital "T" rather than an "I". The notching would amount to about 1/4" or the thickness of the plate welding to the bottom of the flange. Pretty minor notching and the ceiling is flush. I really liked the idea. If you have to recess a beam and only have the depth of a 2 X 10 then your application may allow two beams side by side with less verticle height. I don't know if that works...just an idea.Thor
*Blue, my thoughts on notching were more along the lines of shaving 1/4" or so off the top so you can slide the joist up to the web and keep everything flush on top.Thor, I've got a number of beams going into my house to open the floor spaces. Worst is going to be the main floor. 40' clear span using some ungodly heavy beam specced by the Engineer. Because the house is exsiting, the beam will be dropped in flush with the exisiting floor joists. No options for resting on the flange because the beam can't be raised into position from below. Can't even man-handle the beam in from outside, because it would have to be manouvered across another 10' of open basement (floorless) to get to it's final position. I'm guessing a crane will be manditory. Shouldn't be too bad, because I can work it in with the removal of the existing roof (which is being replaced) and the second floor beam is close enough in line with the main floor that I think I can have them hoisted in one after another. The second floor beam is actually a "T" arrangement with one beam spanning side to side, and a second beam spanning mid beam to the other end of the house. At least I don't have to worry about trampling the flowers, because the yard hasn't been scaped yet.I figure I'll have the beams drilled and then bolt up a stack of 2x8's to pad out the thickness of the flange and provide a nailing surface for joist hangers. There's no flange support (I need the gap between the flange and the joist bottom to run wiring and pipe). The Engineer wasn't too concerned about bolt spacing or sizing. Anyone have any recommendations?
*Interesting. Just as I was composing my reply to Blue he must have been doing his. I had just looked at the thread...finished mine off and pushed the post button. When it went back to the thread there was Blue again...cybermagic!Scott: Pretty major beams. All this remodeling on a house that hasn't been landscaped yet? Your house? Of course if you are like my brother (look Southeast to Bemidji, MN) landscaping consists of volunteer growth on piles left around the site. Now if you were in upscale Moosejaw........I am forwarding this stuff to my engineer, including your bolting question...will post back any response here. However, 2 X 8's? Won't you be hanging beams that will allow you deeper joists and still provide room for wiring etc.?Thor
*Existing floor joists are 2x8. Deeper joists would result in an equal loss of headroom. The house is over 90 years old, the landscape is whatever crab grass and weeds have been able to survive. Actually, it looks more like a moonscape at the moment from all the diggin (replace sewer and water mains, etc)
*Actually, the bolt details are on the engineers drawings (just haven't looked at them almost a year). 1/2" bolts and washers, 24" O.C. staggered. On the detail drawing, staggered appears to be 2" from either board edge (top and bottom edge), 4 boards thick (2 boards either side of the web to fill out the flange).
*40' clear span on the main floor? What did you find to do that?
*Sorry, my mistake. The house length is 40 feet, the actual span of the beam in this instance is only 26'-6 and since the second floor above it is also clear spanned, it doesn't have to carry either second floor loads or roof loads. The Engineer drew up a W12x26 to do the job. Still too much to be man handled by the friends and neighbors.
*Scott: During my reading research for this upcoming project I came across a letter to the editor in the Journal of Light Construction 12/99 issue from a PE named Steve Banik in Shrewsbury, VT. He referred to to an article "Flitch Beam Retrofit" (9/99 issue). Unfortunately I can't find that issue but Banik's concern was bolt shear and bolting patterns. To paraphrase: when floor and roof loads are transferred to something bolted (in this case 2 X 10's sandwiched a 2 X 9 X 3/4" steel plate) you have to consider the number of bolts, their size and shear capacity and placement.The beam in the article must have had bolts 24 OC. Banik calculated that 3/4" bolts shear capacity at about 300 pounds depending on the wood species. When a 24" OC spacing is used the load would have to be less than 150 pounds per linear foot...which he thought unlikely in the article example. He also noted that the National Design Specification for Wood Construction mandates an edge distance requirement of four times the bolt diameter for perpendicular to grain loading.Banik's letter caused the contractor to revisit the issue with his architect who admitted not giving enough attention to shear and edge distance. They went back to the homeowner, opened the ceiling and added additional bolting on 12" centers with the proper edge distance. If you have ever had to drill a 3/4" hole sideways, in the air, you know how nice it would have been to get it done right the first time. The homeowners were impressed...so am I.It sounds like you want your 2 X 8's up off the flange so your situation may be similar to a flitch plate beam. Plus if you are going to "stack" that 2X stock it would seem that you are adding more leverage onto that bolt...making the shear problem more of a concern. I'm guessing that the species of wood has to do with its ability to resist fiber compression when the load from the floor joists transfers from the stack and from there to the bolts...and maybe splitting too.Your engineer should know your particular load and I don't have the original article (yet) but thought you might like the additional info.I was also wondering about that 40' span as I passed under an interstate overpass....figured maybe you were one of the "little people" that show up around St. Patrick's Day and didn't need much headroom. :)Thor