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Discussion Starter · #1 ·
I don't know if this is the proper forum for this, but I am undertaking a project in a 1927 Bungalow to fix a number of issues with the first floor of the house and thought I'd document it here and invite comment along the way. Hopefully it will help others out in the future and help me out if I'm doing something that could be done "better".

Problems:
1) Floors are sagging
2) Joists are 2X8 spanning 13"11 and 14'1" and bending downward
3) Under the 4 load bearing walls there are no columns or extra support (only a double 2X8 joist)
4) Joists are notched and hanging on by a thread in the center beam of the house (3 2X8's sandwiched together) on a ledger strip that's about 2X2 at best. (On the other side they are properly resting on a sill plate on the foundation.

Interesting Fact:
1) Approx 10 years ago (who knows in reality) a second floor addition was built with no additional support on the first floor. My PE informed me that all the weight is coming down on two load bearing walls of the house and below these load bearing walls are 2 2X8 13'1" joists sandwiched together. Woah!
2) We discovered through some detective work that the existing lally column under the main beam of the house has no footer, they are just on the concrete slab.
3) We also discovered that there USED to be columns under the load bearing walls, but they were removed and there are no footers there either.


So, the PE ran all the numbers and the plan is:

1) Install proper (24X24X12 with 3#5 each way rebar) footers under every 4" column to be installed. (6 in total)
2) Jack all joists to level with lots of 20-ton bottle jacks and lots of 8X8 lumber
3) Sister every existing 2X8 with machine graded SYP #2
4) Install 4" lally columns under the load bearing walls to split the span in half
5) Install 4" lally colums under the main beam of the house
6) Sister the existing joists under the load bearing walls with LVLs on each side
7) Remove the existing ledger strip and replace with joist hangers
8) Clean up all the horrible electrical/plumbing mess over the years

Turns out that the existing 2X8 floor joists are 1.75" wide actual width, so the new width once they are sistered with the new 2X8 SYP#2 joists will be 3.25" wide which is requiring custom made joist hangers.


OK, I think that's enough for now, I'll post a few pictures of the main beam, and floor as we're going to be cutting out the slab today to prepare the ground for the new footers.
 

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this will be fun to watch. post pictures please.

I think most of us have been on a job like this. good luck. have fun.
 

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Please complete your profile, and continue to the intro page and tell us a little about yourself and your professional experience, thankyou and welcome to ct"
gmod
 

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Discussion Starter · #5 ·
Picture of the existing floor joists and ledger strip:







The existing center lally just sitting on the slab:



Existing Center Lally:





Picture of one of the existing double joists supporting a load bearing wall:





Closeup of how the existing top of the lally is supported:
 

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Discussion Starter · #6 ·
The water cooled diamond cutting saw:




First Footer cut out (2'X2'):




I dunno, maybe 2" thick? Great slab:



Rest of the cuts in the center:

 

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Discussion Starter · #12 ·
looks like the one on the right has anchor drilled into it. probably pulled on a bolt in the anchor.

got the shovel warmed up?
Correct! Drilled a 3/4" hole with a masonry bit, anchored it, eye hook bolt to pull it out. The two we did not pull out still have columns on top of them, but the ground underneath is sufficiently compacted so they did not move hardly at all after being cut.


Shovels are ready to go for Monday. We're doing our final rundown of materials today, picking up some last remaining items and double checking all our numbers before we move forward. I'll post some more pics of the materials later today.
 

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Discussion Starter · #15 ·
Actually, I would like to open this question up to the group: Now that I have the concrete cut out to pour the footers where the 4" pipe columns will be resting, what's the suggested method for doing so? We're doing 24X24X12 footers, but there are several options (I have marked with a "*" the option I was planning to do):

1) Expansion joint? (yes/no*)
2) ACTUAL footer depth:
a) Should the footer be 12" deep measuring from the top of the slab?
b) Should the footer be 12" deep measuring from the bottom of the slab? (Effectively 2" extra since the slab depth is 2")
c) Should the footer be 12" deep measuring from 6" below the top of the slab?* (Effectively 6" extra)
3) Pipe column attachment to footer?
a) put the pipe column attachment plate in the footer while the concrete is wet then bolt the pipe column to the plate after the concrete is dry
b) put the pipe column attachment plate in the footer with bolts protruding upwards while the concrete is wet and then attach the pipe column to the bolts after the concrete is dry
c) pour the footer 6" below the top of the concrete, put the pipe column attachment plate with bolts in the concrete while still wet, then after it dries attach the pipe column, then pour the rest of the concrete to level with the slab.*

Comments welcome.
 

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slab depth - 12" plus the slab thickness.
expansion joint - yes, keep the footer/slab pour separated from the existing slab. it can be all one pour inside the cut-out
column - to avoid a second pour, I would pour and finish the footer/slab, then place the column foot onto the slab after it has cured. Time for 85% strength is 7 days if I remember correctly.
Is there an Engineer involved? Ask them for details.

if you can do a second pour (schedule wise) pour the footer, place the column and bear weight after 7 days and then top up the slab would look better, IMHO.

poly under the footer? rebar pattern? how are you supporting the floor after removing the other posts?

don't rush it.
 

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Discussion Starter · #17 · (Edited)
...

poly under the footer? rebar pattern? how are you supporting the floor after removing the other posts?

don't rush it.
We've got plenty of time here ($$$), so the goal is to go slow and do it right. We're going to do 2 pours.

Wasn't planning on doing poly under the footer, but that's a good idea even though our soil is pretty moist, I think I'll add that to the plan.

Yes, rebar, 3#5 each way for ALL footers. (Should have mentioned that)

As for supporting the floor, right now it's NOT supported in 4 places where we are adding columns :) Where the other 2 columns are we will be jacking up the entire floor, so we will have multiple floor jacks with 4" columns supporting it. I was planning to use 8X8 lumber in 12' lengths both beneath and above the jacks, so the configuration will look like this:

On the floor - 8"X8"X12' lumber with two 20 ton bottle jacks about 2 feet from either end sitting on 1/2" thick steel plates.

On the bottle jacks themselves - 4" steel column

On top of the 2 steel columns across the floor joists - 8'X8'X12" lumber

Then SLOWLY (1/8" in the morning, 1/8" at night) jack the joists to level.

Sort of like this picture here, except only one 8X8 on the floor, well, actually, exactly like this picture:

 

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Did you cut your squares exactly 24" x 24"? Or did you cut them bigger? Curious because if you cut them the size of the footer, then how are you going to build your form? Or were you just planning on pouring them into the dirt?
 

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forms would not be required. pour to the dug sidewall.

You could likely get more aggressive with the jacks early in the program.

Problem with your approach is that Hydraulic jacks have been known to loss their oil over time, so I would suggest that you have a look at another approach to maintaining the elevation throughout the day/night. Maybe place a screw jack beside each hyd jack, or another lolly post the can be snugged with a screw adjustment? or a shimmable set-up? Wedges?

Also, set the jacks on some 2 x material with 3/4 " plywood pieces on top of and under them so the load gets transfered across both bottom beams equally. make the plywood and 2 by's at least as wide as the pair of 8x's. (Sandwich the 2x's with 3/4 ply top and bottom, set the length of the 2x's across the beams).

Another thing, drill holes into the 6x6 steel plate and loosely screw them up on the beam. It will be easier to deal with something screwed in place and it won't come crashing down.
Try to nail up some sort of frame to place around the 6 x 6 steel plate so the lolly post gets trapped up top in case something goes wrong. (Not that anything will.) or use plumber's strap to hold that lolly post up?

I've done this a few times... :lol:
 

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Discussion Starter · #20 ·
Did you cut your squares exactly 24" x 24"? Or did you cut them bigger? Curious because if you cut them the size of the footer, then how are you going to build your form? Or were you just planning on pouring them into the dirt?
Cut them exactly 24"x24". Plan is to pour them with NO form. At most I will line the walls with some blue-sill foam, or poly sheets. Maybe a combo, poly on the bottom, foam on the sidewalls.
 
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