Tag: beam

Beam Project: Temporary Wall

January 12, 2013 / / 3 Comments

Temporary wall

There are three segments to the wood beam in the basement, so for our purposes we’ll say front, middle, and back. I started work on the middle section because it was the lowest and I wanted to bring it to the same level as the other two. As of last weekend, the beam was as close to level as was feasible, given that the joists themselves aren’t exactly level in the outside walls, nor of the same thickness from one end to the other. I also discovered the importance of measuring level from the top of the floor joist rather than the bottom.

Once the beam was where it needed to be, we started building temporary wall sections. These are standard 2x4s with bottom and top plates. The studs are aligned with the floor joists so that there is even support and as little movement as possible once the existing beam is removed. I started out using the scrap lumber we had saved from the basement demo. Unfortunately nearly all of these studs were too short due to rot and rats chewing a raceway through the wall. I cut them down to 5′ lengths and built a second tier with short cripple studs, then put a cross brace across it. After it was all assembled and in place, I decided it wasn’t going to work.

The problem was partly that the salvaged studs were a bit wonky and uneven and partly that even with the cross bracing I was concerned it was going to buckle if the weight of the house was put on it. Given the importance of the wall in supporting the house while the beam is replaced, we decided to play it safe and get new studs. We can always reuse these down the road, so it shouldn’t add any additional waste to the project and it only cost about $100. That seemed like a small price to pay to keep the house from collapsing.

Temporary Wall Under Joists

We rebuilt the temporary wall along the length of the middle beam. I also built a segment on the opposite side where the joists were cut to provide support for that section. I still need to add cross bracing to ensure it’s stable. I’ll wind up using the salvaged lengths I cut down for the top and bottom plates as well as the cross bracing.

Beam Project: Leveling with a Hydraulic Jack

January 4, 2013 / / 6 Comments
Hydraulic Jack

Hydraulic Jack

Heh, heh, heh. This is more what I had in mind. Wednesday evening my new 50 ton hydraulic bottle jacks were waiting on the porch from UPS when we got back from Home Depot. The boxes were small but said “team lift” on the side. I picked them both up and discovered why: they’re freaking heavy! I bought two of them with the thinking that I may need to use a temporary beam and jack both sides. For the moment I’m only using one. They were $130 each on Amazon, which isn’t cheap considering I’m not likely to need them in the future, but I’m operating under the assumption that anything I need to buy will still be far cheaper than paying fifteen grand to have someone else do it. I can always turn around and sell them on Craigslist when we’re done.

Steel plates

Steel plates

I cut off the rotted portion of the column I removed previously. I wound up having to cut it down a second time so that it would fit between the jack and the beam. It was so big I actually had to make a cut from either side with my miter saw and then use a bow saw to finish it off. Then I put a stack of four 16 gauge steel plates between the jack and the wood to spread the load across the entire base of the column. I wanted quarter-inch steel, but I couldn’t find it and these were only $1.41 each. Four of them adds up to a quarter inch, so I’m calling it good enough.

After following the priming instructions for the jack I carefully leveled the column over it and lined it up underneath the beam, in line with one of the lowest joists. With some re-checking of the level after each pump on the jack I got it snug and right where I wanted it. Then I set up the laser level and marked a starting line on the column to keep track of how much it moved. This means the height of the level can’t change, and because my tripod is rather flimsy I put it on top of one of the 4x4s that I had taken out of the wall. I’m tempted to write “do not move” on the 4×4, just in case.

Laser line

Laser line

I’m taking it slow, but it moved pretty easily at first as the column got a bit tighter up to the beam. Then the noises started. Nothing loud, no groans or anything so far, but little pops and snaps that were extremely unnerving. The beam has a split in it –which is normal– but it appears to be getting wider as we push on it. I made some marks at the ends of the crack to keep an eye on it. After about a dozen pumps on the jack it started getting resistance and I started getting freaked out that bits of wood were going to splinter and fly as a precursor to some catastrophic failure of the beam… but that didn’t happen, at least not yet. Sarah came down and gave the jack a couple of pumps. For me it was as much a symbolic “we’re in this together” as anything, but it made me feel a little better.

We left it overnight, but this weekend I’ll be back at it. The beam needs to lift over an inch in this section, which is pretty dramatic as these things go. Once this section is level (assuming the beam doesn’t fail) I’ll build the temporary support walls, move the jack, and then do it again.

Beam Project: Leveling with Jack Posts

December 28, 2012 / / 4 Comments
Jack post

Jack post

I bought a jack post. Then I bought two more. Then I bought a big adjustable wrench to have more leverage to crank them. The end result, after several attempts (other than a straining workout) is that in the single section I was trying to lift the beam, it has moved up approximately an eighth of an inch. Since I’m trying to raise it by over an inch, I decided to rethink my tactic.

Cut floor joists

Cut floor joists

Part of the problem is that several of the floor joists, which are 2x10s spanning the whole width of the house, were cut at some point to allow access to the basement from the front bedroom on the first floor. This was then closed up at a later date. When they cut the joists they were no longer supported by the outside wall on one side, resting entirely on the beam. Generally you would add a cross member (or a few) to tie the cut joists to the joists that were not cut. Instead, someone probably much later put in some 2x4s so they’d have something to hang drywall from. Not surprisingly this is now the lowest part of the beam, since it’s bearing considerably more weight than it was designed to. We’ll replace the cut joists when we rip up the first floor subfloor, but for now we need to work with what we’ve got.

Another problem is that the jack posts I bought ($45 a piece from Menards) are rated for between 9,100 and 18,000 lbs. That sounded like a lot, but recalling that we removed 9 tons during first floor demo alone, it’s very likely that the weight the beam is carrying is higher than that. The dome in the steel plate at the top of each jack post has buckled, which is probably a good sign they’re not up to the task.

Jack posts and rotted column (base)

Jack posts and rotted column (top) Jack posts and rotted column

After some discussion and research, I arrived at plan B. The first step was to move the jack posts to either side of the rotted column a bit further down the beam and take any remaining load off of that section. Then I took out the column, which by this point was basically hanging from the beam.

Rotted column removed

Rotted column removed Rotted column removed

The damp dirt beneath the column explains the rot, but it’s concerning since I don’t yet know where the moisture is coming from. That mystery will need to wait until we dig up the floor. With the column removed I can now cut off the rotted section and use it in conjunction with the 50 ton hydraulic bottle jacks I ordered, which will arrive in a few days. I’m pretty sure they’ll have the necessary strength to lift the other section of the beam up. I’ll cover that in more detail when they show up.