Replacing damaged center beam in old house

Reply

  #1  
Old 12-11-12, 02:48 AM
C
Member
Thread Starter
Join Date: Jan 2012
Location: USA
Posts: 263
Received 0 Votes on 0 Posts
Replacing damaged center beam in old house

This thread kind of goes along with another I recently posted about joist bracing (http://www.doityourself.com/forum/fr...sistering.html)

When I bought my house it had a badly damaged center beam. About 4ft of it had termite damage and some idiot plumber decided it was cool to notch out about 35% of the beam to accommodate his heating pipe run. Someone put a couple jack stands there maybe 30+ years ago but at the time I'd bought the house one of them had fallen over and the other was loose enough to move by hand (I have no idea...).

Anyways, my quick fix was to cutout the termite damaged wood and replace with new wood, pour a nice big footer, and put 3 jack stands at the break. In the process I jacked the broken/sunken point of the beam up 6-8", giving me plenty of busted plaster to fix in the months ahead.

I'm using the basement quite a bit now and am tired of having the steel posts in the way, and would also like to gain some headroom. I'm 6' 1" and much of the basement measures around 74" floor to bottom of joist. Over the years I've moved pretty much every single utility up into the joists and this beam is one of the only things that sticks down in an otherwise clear ceiling.

I'm trying to figure out if I can replace what is there with an LVL and/or steel beam that is the same width as the floor joists - 7.25" so it doesn't affect headroom. The beam spans 12' 7" and was originally 3 2x10's with 2x4's on either side for the joists to rest on. Strangely, the top of the beam is 1.5" below the subfloor, and the joists are notched to extend overtop of the beam. So the joists a) rest on the 2x4's, b) rest on the top of the beam, and c) are toe-nailed in place. This is strange to me, but it's an old house..

The center beam breaks up a 26' wide span (11' and 15') and rests on exterior foundation wall one end, and interior foundation wall (part of the chimney structure) on the other. If I could get away with 3 or 4 1.75x7.25" LVL beams that would be great. Next best is 3 LVL laminated with a steel plate. I-beam might work but I don't think there's a standard size to match 2x8 height. I've been poking around with span charts, deflection calculators, and whatnot online but it still seems a bit black magic to me. Just looking for some direction here, and I'm not really interested in hiring an engineer - I could probably do the job wrong and then right for less (but more likely right the first time).

Thanks!


 
  #2  
Old 12-11-12, 11:10 AM
P
Temporarily Suspended
Join Date: Jul 2008
Location: NY
Posts: 10,982
Received 0 Votes on 0 Posts
My guess is that a steel beam would cover building codes but I'm not sure about 2x6s. I would check with a local architect. The last thing that you want is that you can't sell the house because of that beam.
 
  #3  
Old 12-11-12, 04:51 PM
BridgeMan45's Avatar
Member
Join Date: Oct 2011
Location: USA
Posts: 3,194
Received 1 Vote on 1 Post
I'd suggest you contact the manufacturer of the LVLs you plan to use, trying first to work through the local dealer selling them. All LVL manufacturers have technical people (available with an 800-number phone call) who can tell you what will work for your loading conditions. Unfortunately, sometimes they refuse to "think outside of the box," which is what you may need for your application. That is where hiring a local engineer would be a significant advantage. Hire the architect that Pulpo suggested if you just want everything to look pretty, but aren't concerned that the support system remains standing.

P.S. You will have some electrical corrective work to do if you ever decide to sell the place--I believe the National Electrical Code only allows a maximum of 4 individual runs of romex (could even be 3) to be bundled together, with it looking like more than that running through the holes in your joists in the picture.
 
  #4  
Old 12-11-12, 10:28 PM
Nashkat1's Avatar
Member
Join Date: Mar 2012
Location: USA
Posts: 8,469
Received 2 Votes on 2 Posts
All kinds of interesting stuff in that ceiling! Not just too many cables run through some openings, but a run of 14-2 supported by draping across other cables, what looks like a U-bend in a gas pipe to pass under the king joist, and a bundle of 12 gauge cables used as a storage rack - haven't seen that one before.

What was your question? Oh, yeah, about replacing the king joist. You need a report from a professional structural engineer who can visit and inspect your basement in person.

Can't advise you from here. Sorry
 
  #5  
Old 12-12-12, 01:56 AM
C
Member
Thread Starter
Join Date: Jan 2012
Location: USA
Posts: 263
Received 0 Votes on 0 Posts
The space you're looking at is below the kitchen which I have not yet renovated, so some things will change.

I actually just put in that funny little gas pipe bend when I redid the whole line - it's purposely routed like that so I could have clearance to remove and replace the beam when I wanted. It will get tidied up at some point. In the meantime, is it against code?

Lots of my exposed wire stays staple-free since I keep changing things. Of course I can easily run around and tack things down when needed. From reading around it seems that if you have 9 or less current-carrying conductors bundled (24" or more) then you're still good for 20A. I think you see 5 cables in that bundle, so I'm a tad over, but it's an easy change when I rewire the kitchen. It's the only run in the house that has that many cables. I don't like drilling more runs until I have a plan so I always do what I can with the existing holes first. The 14-2 you pointed out was actually the only grounded wiring in the house when I bought it, and it will go away soon enough.

As for storing things up in the joists, give me a break! At least no one made fun of my pvc drain run...
 
  #6  
Old 12-12-12, 02:05 AM
BridgeMan45's Avatar
Member
Join Date: Oct 2011
Location: USA
Posts: 3,194
Received 1 Vote on 1 Post
I'd like to give you more than a break. You're actually doing a rather tidy job of getting things in order, and for that, I commend you. Far more orderly and precise than a lot of the stuff done by homeoweners these days.

Sehr gute, mein Herr!

P. S. Regarding the original center beam replacement question, you might consider a heavy steel section, shallow enough but heavy enough to allow the joists to rest on the bottom flanges. If you're in an urban area, decent salvaged stuff is often available for a song.
 
  #7  
Old 12-12-12, 02:07 AM
C
Member
Thread Starter
Join Date: Jan 2012
Location: USA
Posts: 263
Received 0 Votes on 0 Posts
Here's the real 'before photo:



Yes, that's 6 individually metered fuse boxes
 
  #8  
Old 12-12-12, 02:12 AM
BridgeMan45's Avatar
Member
Join Date: Oct 2011
Location: USA
Posts: 3,194
Received 1 Vote on 1 Post
Yikes! Previous owner must have been a burned-out wire-twister (electrician). You've definitely made progress.
 
  #9  
Old 12-12-12, 02:28 AM
C
Member
Thread Starter
Join Date: Jan 2012
Location: USA
Posts: 263
Received 0 Votes on 0 Posts
Regarding the original center beam replacement question, you might consider a heavy steel section, shallow enough but heavy enough to allow the joists to rest on the bottom flanges. If you're in an urban area, decent salvaged stuff is often available for a song.
Do you mean an I-beam with the joists between the flanges, or and up-side-down T-beam? I want something I can add wood to either side so I can nail in joist hangers.

The scrapyard will be my first stop after I figure out what I need. I found some smaller I-beams there to help with jacking up and straightening out my house years ago. Pretty cheap and in great shape, and after I finally decided I was done with them, I sold them back to the scrapyard - a much cheaper experience than any tool rental place
 
  #10  
Old 12-12-12, 12:39 PM
BridgeMan45's Avatar
Member
Join Date: Oct 2011
Location: USA
Posts: 3,194
Received 1 Vote on 1 Post
Trying to locate a salvage T-beam of hefty enough dimensions is not likely to happen--they can be extremely scarce, at least in most areas of the country I've worked with steel in. Far more likely to stumble onto a wide-flange/WF beam (what you're calling an I-beam), as they are used more commonly than T-sections. A typical W 6x25 will have a section modulus of 16.7 C.I., while a comparable WT 6x25 has a section modulus of only 3.79 C.I. (meaning it's not even one-fourth as strong in bending). FWIW, an inverted T-section will also have considerably less shear capacity near its support locations, unless you build up the webs using welded web stiffeners. The obvious advantage of the T-section would be the ability to slide it right up from the bottom against the joists.

If you use any type of steel beam, joist hangers wouldn't be needed. A pre-drilled web hole at each joist location would accommodate short angle clips, with a single bolt through each at the joists' neutral axes. WF beams, with their parallel flanges, would enable you to slide the joists in without any trimming. Or actually, slide the beam in from an exposed end access location. I-beams, with their tapered flanges, would require each joist end bottom to be taper-cut to bear uniformly.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: