Greetings all from the House From Hell.
On tonight’s entertainment: how to replace a beam that was undersized when it was installed, then cheerfully hacked above and below by hack remodellers. I have an engineer. I was hoping to get away with sistering, but he says that because it was undersized (4×10 over 11′ span) the sisters (LVLs) would have to go all the way to ends and be supported. On one end, a corner of an inside wall could be built out to add support; at the other end, there’s a stove and cabinetry. Kitchen remodeling is not an option. I am trying to figure out how to support the load above while taking out the old beam. The situation is that this is over a kitchen, holding up second floor load-bearing wall and roof. The only good news is that the room above is gutted, nothing but joists and ceiling. There is though a failing splice in the top plate of the second floor wall, currently held together by a 2×10 header retrofitted into a window RO under the splice (was this house built to fail or what?). There is no bottom plate, the second floor wall studs all sit right on the beams (which are visibly deflected, one about 3/8″ more than the other). I’d appreciate a reality check on my plan:
- Fasten a 2×6 ledger to the bottom of the second floor wall studs, Simpson 1/4″x4.5″ screws. Then fasten a 2×4 ledger to this. This gives a 3″ bearing for studs from the kitchen floor below to hold up this ledger. This takes the load of the wall and roof above. Studs fastened to 2×4 bottom plate that sits on tile floor in kitchen. Perhaps run strap ties to 2nd floor joists to prevent the wall falling out.
- Put supports (plates and studs) under ceiling joists on one side of beam, 2nd floor joists on other side of the beam, to hold them up when the beam is cut away.
- Cut the joists, cut 2nd floor studs 1.5″ above beam, cut away the beam.
- Bottom plate for second floor wall.
- Build the beam (2 9-1/4″x1-1/4″ LVLs with 3/4″ plywood spacer, or maybe just 3 layers of LVL) in place (easier to negotiate it in in pieces rather than try to squeeze the whole thing in).
Replies
As a follow-up, here are some pix:
Anyone want a fixer-upper?
Have your engineer design the bolt pattern needed to lag bolt a 3-1/2" or 4" by 1/4 steel plate to the bottom edge of the beam to make a built up beam.
Probably the easiest way to go if you have access to a drill press, as you do not want sloppy holes, they need to be tight around the lag bolts. .
The pix is an example of such a plate, the 1/8" by 6" plate here doubled the strength of an existing 16 ft 6x12 to allow storage above the garage.
Thanks for the suggestion.He talked about putting a steel beam underneath this, that would basically take all of the load. But it would require support at either end, and that stove at one end got in the way. Earlier he had mentioned a flitch plate, I had argued against it because of nails especially for a ledger that (notched) 2nd floor joists rest on (those old framers....).I have heard of a steel plate screwed into the bottom of a beam to reinforce it, using long #8 screws (nothing bigger so as not to weaken it). I'll run these ideas by him. But my impression is that at this point the calculations say that reinforcing the beam along its span is no good if the support at the ends is not strengthened.Another idea he tossed around is a glulam under the beam, but the hangers for those take about a billion 16d nails and we have no header, just 4x4 top plates. So we need supports.....He called today basically to give me the bad news on sistering and give me the holiday weekend to talk myself into replacing.....
Art - I know you are one smart SOB, and I really like the use of flitch plates and steel in general, but when you said "...the 1/8" by 6" plate here doubled the strength of an existing 16 ft 6x12..." did you do calculations to determine that that plate litterally "doubled" the beam's capacity? Or is that a seat of the pants calculation?Tipi, Tipi, Tipi!
http://www.asmallwoodworkingcompany.com
Yep, did the calculations, based on equations in "Elements of Strength of Materials", by Timeshenko and Young, my first structures textbook from 45 years ago.
BTW: If the end supports are sufficient for the load, the steel plate on the bottom does NOT need to be in bearing - note on the pix that the steel plate stops a few iches short of the end of the beam. Note also how many bolts there are - they are for shear strength, not to hold the steel up.
Basically this type of built up beam is MUCH more effective than a flitch plate, as the oveall assembled beam becomes an equivalent of a steel T-beam. The trick is there needs to be a LOT of bolts near the ends to take the lateral shear.
I have had no problem using 3/8 lag bolts in 2X DFir or SYP when properly predrilled - dont think one could use enough #8 screws to give the shear strengh required.
Here is a link (first good hit on google for "built up beam" for the type of calculations, although for an all steel reinforced beam. For wood and steel , divide the thickness of the wood by about 20X (ratio of working tenile strength) and treat as steel - equations more complex when calculating deflection.
Note that the google hits included a lot of flitch type structures, which are not really 'Built up' requiring shear calculations, only vertical laminations.
http://www.ijee.dit.ie/OnlinePapers/Interactive/Philpot/shear_flow_builtup.htm
Thanks, Art.
In large part, you're relying on those lags for sheer then? I was thinking they were to keep that steel from "rolling", similar to the top and bottom flages on an I-beam.
As soon as we start talking deflection and tensile, we're beyond anything I can add to the discussion except for gut reactions based on what I've seen/done over the years - nothing I'd be comfortable recommending to anyone else. Tipi, Tipi, Tipi!
http://www.asmallwoodworkingcompany.com
Yep, for shear. In the pix the plate is on the bottom of the beam, the pix is 'rolled' on its side (aka the lamp on the wall).
Taylor: If you bolt a strap to the bottom of the existing beam/joists, all you do is tack the palte up, put a jack under the middle to preload the existing beam (withthe steel palte in place) and then bolt it up.
Hmm, nobody has responded to the original question: how do you support a wall that is sitting on top of a beam, while you replace the beam?
And just to make it interesting, the wall has no bottom plate and the top plate is basically snapped in the middle.
I'd appreciate a reality check on my plan:
Your plan sounds pretty good. Are you saying that the floor joists for second floor are exposed so you can get to them them directly from the kitchen? If so, that's fine. And your using a plate on the tile floor is good so you distribute the load and are less likely to crack tiles. You probaly know that if you build a stud wall on the kitchen floor and try to tilt it up, the edge of the top plate will hit on the way up (unless you can get it in beteen joists and then move it).
Easier to put down you bottom plate (I guess I would even see about glueing it temporarily (caulk?) so it doesn't slide out) and lift your wall with its own top and bottom plate onto this first plate. Use wedges/shims to tighten. You can also make "A" frames with 2x4's longer than the distance between floors, nail the tops so they touch each other to a plate temporarily fastened to the floor joists and pull the bottoms toward each other to "spring" them into place and put pressure on the second floor. I would also toe nail their bottoms to a plate (being careful nails don't go through to the tile beneath!) That's easier than building a stud wall and I think it gives more upward force.
And, watch, look and listen while working for signs of anything letting go! Good luck!
Thanks, any temporary stud wall I try to put up will have to be built in place. There's no room to tilt up a wall. I'm also worried about being unable to fasten the bottom plate into the floor, I'll take your suggestions under advisement.
Since you have to build the wall in place, I would consider the A-frame thing. The plate would probably only need to be fastened to the floor if you were tipping a wall up, to keep the plate in place while doing that. If you are building in place, probably no need to fasten plate to floor. If you wnated to, I suppose something like double stick tape, or even some foam rubber under the plate would give it "grip".
Here's a good example of the "A-frame" style supporting wall. Maybe a bit overbuilt, but hey, it's holding up half the house!
View Image
Edited 7/1/2006 12:35 pm by wrudiger
Ah thank you (and thanks Danno) now I understand how the A-frame idea fits here!
Thanks, I (or maybe he) needed that! Picture is worth a thousand words!
Your proposed plan sounds all right. I'd put a 2x6 on both sides of the studs rather than doubles on one side. But when you build your shoring walls, make sure you can get maneuver your LVLs into place. May be better to have them on horses below their final position before you build the walls.
I'll only comment on the thing that jumped out the most.
Many of your solutions for the beam seem to be hindered by the end supports, yet unless I'm not getting the whole picture there are fairly easy ways to increase the bearing, especially if there is a face mount hanger available.
You mentioned that a big face hanger would work if there was more than a 4" bottom plate to attach it to. Many times we'll have a similar situation and an LVL is cut, notched, and otherwise fitted above the plate to privide a solid surface to nail the hanger to. Sometimes this requires a little work to properly support the LVL so it stays vertical, but there are few situations where this can't be done with the plethera of hangers and mending plates available.
Sometimes the LVL is attached in the wall above the beam and a hanger with long side straps travels up and/or over the LVL for solid attachement.
Basically, end bearing should be the easy part. If your engineer has OKed an easy fix that just needs better end support, you're almost home.
Good building!
Thanks all for your comments. I'm not sure I fully understood everything but I'll be rereading.Re putting a 2x6 on both sides, I think I'd like that too, but the ceiling joists get in the way (I've tried already getting a 11' 2x6 above those joists). If I decide to fur out that side of the beam, I can cut 1.5" off the joists and maybe slide it in that gap, then fur out and reattach joists after beam installation.Not sure I follow how the A-frames would help. The thing is *everything* including the floor joists is relying on this beam. I need to find something to support everything before I cut away the beam. The idea of the built-in-place stud wall is that it is to one side. I need the other side clear because I will need to bring the beam into the pocket (or whatever the hacks have left of the pocket) and then swing it onto the top plate that will support it on the other side.Re glulam hanger, the idea was to have that underneath the beam, but there's just not enough nailing surface to attach a hanger to. If you look carefully at the plates at the pocket end, neither of them has any support underneath them at the post (beyond presumably a few nails) and adding support involves going through siding and sheathing.
> The idea of the built-in-place stud wall is that it is to one side. I need the other side clear because I will need to bring the beam into the pocket ....
Can you post pictures? It's not clear to me what needs to be kept clear. If the beam supports joists to both sides, then both sides will have to be supported by falseworks of some sort. If a temp wall would be in the way, you might be able to do it with a temp beam and columns or cribbing.
Working with these loads is dangerous stuff. You might considery paying a house mover to do that part. Just have the new beam standing by under where it goes. Let them support the load. You put in the new beam, then they put the load back on it. For them, it's an easy day with a nice long lunch. Of course, that may be massive overkill. Without seeing the actual house, it's hard to say.
-- J.S.
Taylor.
On a couple of beam installs I was confronted with the how do I get it in question. Well, I could get it in, but not around the two temp walls. The solution is get the beam in, close as you can to the studs you are cutting out or whatever. Then put up the temps. Cut out the crap, raise the beam.
Or, cut a hole in the wall and shove that sucker through. Whatever works. The music of logistics.A great place for Information, Comraderie, and a sucker punch.
Remodeling Contractor just outside the Glass City.
Quittin' Time
"'d appreciate a reality check on my plan: "
OK. U have alot of good questions. Some basic and some not so ...
but not understanding the very basics of the laod path ... ie ... the ends of the beam ... tell me you should not be tackling this not so basic project yourself.
Jeff
Buck Construction
Artistry In Carpentry
Pittsburgh Pa
not understanding the very basics of the laod path ... ie ... the ends of the beam ...
What have I said that demonstrates not understanding the load path?
If it's my comment about the pocket end that "I don't know what's holding it up," that is because the pocket is so f***ed up by hack contractors that there's not much support left there. I'll have to fill that in as best I can.
At this point, I'd say I understand a hell of a lot more than the geniuses that cut away joists, studs and beams as part of remodelling through the life of this house.
So your 20 Year old beam is sagging? and you want and feel the need to replace it? One end is supported and the other is iffy? Add extra to the iffy end and bolt a steel "strap" to the underside of the beam for as long as you can. Reason for this is the top is in compression and the bottom is in tension. Tension side is the most likely side to "break". You can jack the beam up a little if you wish but I would just use any jacking to hold the strap during install.
"but he says that because it was undersized (4x10 over 11' span) the sisters (LVLs) would have to go all the way to ends and be supported."
the way I read that, seemed to be you had a problem with it "have to go all the way to the ends and be supported" ... and sounded like you were looking for alternatives for the new support to NOT go all the way to the ends and be supported.
My fault.
U know ay more than anyone else that's worked on your house. And setting retrofit beams under load in a tight space is alays an easy DIY project.
Have at it.
Jeff
Buck Construction
Artistry In Carpentry
Pittsburgh Pa
You had me going for a minute.I'm not sure I will do this myself, but after the fiasco I had with someone replacing some of my joists (I ended up having to tear their work out and redo, so they doubled my work), I'll at least make damn sure I know what will work before I let someone else do it.
Taylor,If there are no door ways above the beam you could add another beam above and hang the old from the new.We just cut the stud nails and turn the studs sideways, install 2x12, add new studs, take out old studs, add another 2x12. Jack old beam up and strap 'em together with steel. Sometimes bolts, sometimes nails.KK
A postscript in case any DIYers come here looking for tips:For replacement, engineer wants 2x8s run perpendicular to the studs, then screwed/nailed to the studs (then supported from below obviously). Wants fasteners capable of 1000lbs shear strength per stud (that's about 4 Simpson 1/4" heat-treated screws).Good point above about basement. He wants support going down to the basement floor. I know we have some kitchen floor joists notched for steam pipes. Of course that will require taking down the basement ceiling and dealing (having someone deal with) asbestos cladding on steam pipes.He also told me that technically the beam should not still be standing, probably some kind of truss action from the studs has kept it up. I remember toe-nailing a stud when I was beefing up a window header, and I swear I felt the thing move underneath me.Thanks again for helpful suggestions, still looking at alternatives.....
Taylor, what fine kettle of fish have you gotten yourself into? Man, you sure do know how to test a beautiful relationship. Please, extend my regards to your wife.
I see you're from North Jersey. How bout considering attending the Fest on L.I. NY? Weekend of Aug. 18th.A great place for Information, Comraderie, and a sucker punch.
Remodeling Contractor just outside the Glass City.
Quittin' Time
It helps when an engineer comes in and says, the house should not be standing. That and a bit of Stockholm Syndrome.I'll be far far away from these locales come Aug 18, thanks for the invite though.I might even come back.
I can't quite figure out what is going on but if you could build a temp wall under the floor joists and stack another directly above it in the 2nd floor room that should support most of the load for the floor and roof. Then you could build another wall to hold the ceiling. Then you could cut out the old beam. Now it gets interesting. There may be no adequate support on the cabinet stove side to carry the beam. I'm afraid that if you don't determine if the new beam has solid bearing all your hard work will be for not. You should also make sure there is enough support in the basement or crawl under the bearing points of the beam. The engineer should be able to determine that easily enough.