replacing termite eaten center beam?

[PILOON]

We once needed to install 40 ft of 12 in H beam and the closest it could be delivered was about 100 ft.
Using rollers and sheets of plywood we let gravity do most of the work.
I wrapped 3/4 rope around my trailer hitch to act as a brake sort of like a capastan.
As the beam rolled downhill workers guided it with crow bars and kept moving the rollers ahead as they dropped out.
In the building we set up scaffolding at correct height and with levers were able to roll and pry to exact location.. Blocks of wood and a chain lift dropped that I beam into precise position.
We calculated it weighed about 900 lbs. I had cut 6ea 16" lengths of 3" pipe to make the rollers.
Nobody even broke a sweat.

LOL, had we 'lost it' it would have shot out the house lakeside and gone for a swim!

 

[Texasmark]

I built my house in 1979. I poured 48 2x2 footings with Sacrete. Then put old utility poles in for the piers. Did a 6x8 grid with 3 2x6's for the beams and 2x6 joists on top. I figured the creosote in the poles would deter the termites. I was strapped for cash at the time, plus had a schedlule as I only had 60 days to build it and get back to my regular job so I didn't put in termite shields. Other mistake I made was to close in the perimeter with under pinning to keep any varmits from crawling under it and dying. I had vents in the penning, but apparently not enough as rot contributed to the termite damage.

Termites invaded and devastated the beams. I had been doing all my leveling due to soil shifting but this was too much. I hired a company to come out and fix the problem. They had 8 guys with numerous jacks and all. They replaced 5 of the 6 beams which were 36' long with treated 4x6 lumber and dug 5ea 2 1/2 sq ft footings additionally for each beam. They used concrete blocks rather than wood for piers. The job took them about a week and cost me $10k. I couldn't have undertaken a job of that magnitude alone.

The few cracks in the drywall that occurred were easily repaired with spackling paste. It matched the paint on my walls and I didn't even have to repaint.

Moral of the story here is know your limits. Don't take on more than you can handle. Replacing a beam under a house is tough work. It's not like crawling around under there dragging a 20 ton jack and a handfull of shims to shore up a sag.

The money is gone but the work is here and I live in it every day. Money well spent.

Hope this helps.

Mark

 

[BuilderML]

I have not gone thru all the previous post so sorry if i repeat something others have said.
You have a few options on how to go about replacing the beam, you are lucky that your joist extend beyond the beam to allow you to install only one temp (wall,or beam).The side you took your picture from would be the side i would try to work from seeing how it has less stuff in the way. Not sure what the gray box is in the middle. Looks like you need 2 sections of temp support on each side of that gray box. A single length beam (LVL or steel) would be ideal but would also be a pain to work with. If you are going to try to sit in beam pockets on the foundation wall forget about the one piece beam.. Not gonna happen. Also are you putting in new footings where your new post will be installed? Or are you cutting the old ones out and trying to locate in the same spot? That might be a little pain in the ***. Personally i would use an LVL beam you can assemble in basement close to the finish height before jacking into place. Install jack post on your new footings and lift away to make your floor as level "true" as you want. I am sure your plaster cracked on the way down so you can rest assure that you'll be cracking it on the way up..1" is a lot and trying to do it in sections or a whole i would be willing to bet your going to create new cracks and or open up existing ones. You asked early on about how much higher you need to make your temp (wall/beam) to take the weight off the existing beam. No set rule on this you'll figure it out when you do it. One little pointer when you are cutting the nails from the floor joist to the old beam using your sawzall or multitool. If your blade gets pinched you know you need to go up with your temp. wall or beam. I like to use a "wrecking" blade versus a metal blade to cut those nails. You'll find that the gap created by the blade is a good way to figure out if you have shifted the weight over to the temp. beam or wall. I could go on and on but a lot you'll figure out as you go. Kinda one of those things you don't know until you do. This is only a few ideas keep in mind i don't know if you have point loads that require additional support. Just keep it safe. Good luck with your project.

 

[2manyrocks]

I'd like to reuse the existing columns. The present beam is dead center in the house with a stud wall above it. I'm sure the ceiling joists are overlapped in the ceiling on the stud wall.

The only way I see getting a 30' beam in there would be to support the existing floor joists, tear out the beam, make a hole in the exterior foundation and slide in a new beam. In theory, I could support the front of the beam with my FEL and the rear of the beam with my 3 point hitch, but in reality, I'm concerned that I'd knock the house down in the process.

It may just be that I will have to replace the existing beam section by section.

Although I started off thinking I would just build a stud wall, I'm not so sure but what I should use jacks instead because it would be so much easier to lower the house back onto the new beam. These would be really nice to have: Screw Jacks Lifting Support Jack House Floor Leveling Floor Support Sagging Floors Basement

 

[quicksandfarmer]

If I understand correctly, the overall length of the beam is 30' with posts every 10'? And the existing beam is three 2x10's (1.5x9.25?) I'd just replace it with three 2x10's. The existing beam didn't fail because it was undersized, it was eaten away. I might go pressure-treated to avoid a repeat. Can you get a 20' piece in there? If so I'd just splice it over the posts, three 20-footers and three 10' footers, nail the whole thing together with 16d nails. If not I'd go with nine 10-footers, still splice over the posts, but put a 4' or so tie piece along the side of each splice.

You can't get 20-foot 2x10's at a big box store, but a real lumberyard should stock them. My Lowe's has them as a special order.

Since the joists overlap I would run a temporary beam parallel to the main beam and a few inches off, so you have room to work, and lift with jacks there. If we knew how long the joists were we could estimate the load on the beam, but my guess is you'd want to use 8' sections of 4x4 and put two jacks under each section. You'd need four sections, overlapped slightly, and eight jacks. I've used the Tiger jacks from Home Depot, they work fine for this. They're about $50 each so you'd be in for $400 for the job, and you could sell them on Craigslist when you're done.

I jacked up my barn with these jacks this summer, and the key is to go slow. If you pull with all of your might with these you can exert a tremendous amount of force, squashing the plates, crushing the wood of the beam and cracking your concrete floor. With a 12" wrench your mechanical advantage is 3000:1. I found that if I turned the screw to the point of resistance, when I came back a day later the resistance was gone and I could turn it some more. I ended up turning them about 3/4 turn to a full turn every day, using only an 8" wrench and never pulling that hard. The thread pitch on the screw is seven per inch, so that's about 1/8" per day. Over the course of two weeks I took it up two inches without ever exerting that much force. I put a piece of 2x6 on the base of the jack to protect my concrete.

 

[quicksandfarmer]

I need to correct myself -- the mechanical advantage with a 12" wrench is 527:1, not 3000:1. It's still significant.

To get an idea of the forces involved, here's a rough calculation. I'm going to assume the beam goes the long dimension, that would be normal, so with a 30' beam the footprint of the house is no more than 30x30, or 900 square feet. We're only interested in dead load here, and the usual figure is 10 lb/sf, so figure a dead load of 9000 lbs for the first floor. There's probably more for the roof and if there are other floors, but it's hard to know how they're supported, so bear with me. Half of that dead load is borne by the foundation, half by the beam, so figure 4500 lbs on the beam. I've proposed using eight jacks, so that's 560 lbs on each jack. With a 527:1 mechanical advantage in the jack, that's just over one pound of push on your wrench on each jack. Of course I'm not accounting for friction, but the point is take it easy -- you shouldn't be wrenching until your arms give out. Lift until you hit resistance, then give the house a day to settle, and come back and lift some more. It really helps to oil the screws on the jacks, then the resistance you feel is the house resisting bending and not the jack resisting turning.

 

[2manyrocks]

quicksandfarmer, your understanding of the dimensions is correct. 30' beam made up of 3 (2x9.25" oak boards) spanning a little less than 10' from foundation wall to post to post to foundation wall. I haven't measured the outside of the house, but the interior rooms are 13.5' wide so the house is probably about 30x30 on the outside.

Weight wise, it's a single story house with plaster lath walls, but it is oak stud framed. They added on a 8' wide porch on a concrete slab at the back of the house that has a 16' roof line that intersects midway with the old roof. So there is more weight on the stud wall/beam than just a one story house.

Price wise, the metal jack columns from the box stores seem about the best option so far. I liked the idea of being able to run a diagonal brace against 4x4 posts if I used the ellis jacks that I linked a few posts back. does anybody have any tips for bracing metal jack columns?

I'm not sure that I have room to work with a 2x10x20. I would have to come down the outside stairs in the corner and then make the turn with it in the basement.

I've gone back and forth in my mind and in this thread how to approach this project. I really appreciate you folks sharing your wisdom.

 

[quicksandfarmer]

quicksandfarmer, your understanding of the dimensions is correct. 30' beam made up of 3 (2x9.25" oak boards) spanning a little less than 10' from foundation wall to post to post to foundation wall. I haven't measured the outside of the house, but the interior rooms are 13.5' wide so the house is probably about 30x30 on the outside.

Three 2" rough boards would be the same thickness as four finished 2x10's.

It's impossible to tell without seeing the design, but usually the weight of the roof is carried by the exterior walls. So it sounds like there's not a whole lot of weight on that beam.

 

[2manyrocks]

Here is a followup to my experience with this project.

I decided to build a triple layer top plate under the joist tails and a double layer bottom plate with jack posts between them. Working alone, it was easier to manage 2x4s than larger dimension lumber. The jack posts were necessary to raise the house back up to level. I bought a Bosch laser level and then discovered that I had severely underestimated the amount of sag and had to extend the length of the jack posts in a couple of places. Because I was dealing with plaster walls that I did not want to crack, I raised the posts a little each week beginning in 2015, I think, until just recently.

I've seen a lot of internet posts asking how many jack posts are needed. I used 19 of them. Painful to buy, but I told myself that they were cheaper than the ER, hospital, funeral home and cemetery, not to mention having a caved in house.

During the process of raising one section, it just seemed that no matter how much I turned the jack, very little was happening. It turned out that the screw had punched a hole through the jack base. If I were to start this job anew, I'd probably buy some steel and fabricate my own top and bottom plates for these posts. I'd also use bolts instead of the rod that came with the jack posts, and I would grease the screws.

I am very, very grateful for the advice to weld the plate to the top and to weld the piece that holds the screw to the post. This was invaluable advice.

Although I bought pressure treated lumber to replace the beam, I was fortunate to find a used 8 inch I beam at the scrap yard. I was also fortunate that the grade of the yard was very close to the height were the beam needed to be installed in the house. So I built a support wall and slid the I beam in using a come along.

One problem was that the original support posts needed to be extended to make up for the 8 inch I beam going in place of the 9.25" lumber beam. The local tool and die shop cut a couple of extensions to which I welded an inner liner so the extension couldn't slide off the support post. I also added a section of C channel so the I beam couldn't slide off the extension.

During the process of cutting out the old beam, it became apparent that the termite damage was worse than thought. The damage over one support column was so bad that only one of the pieces of lumber was supporting the house in that location. The lumber in the beam pockets was also shot.

At one point, I called a house mover to ask for a quote on this job and was quoted $5,000. It has been a time consuming and difficult project. I agree with Texasmark that one has to know their limits before trying something like this. For anyone considering something like this, I would say to not scrimp on jacks or support materials because your life is at stake.