[Alan]

I finally should have some free time this weekend to get under there and jack up my floor.


I am thinking that I might have an easier time digging the new footing(s) pouring them, and using the footings themselves to support the jacks while I slide a post in next to the jack.


Does this sound reasonable? I figure I need to dig anyway to be able to put lumber underneath the jack to support it anyway. Why not just put in the footing and set the jack right on it?

 

[joecaption]

As long as you make the footings 24 X 24 with rebar in the middle and 6 to 8" thick it will work. Give them at least 2 day to let up, the longer the better.

 

[jomama45]

As long as you make the footings 24 X 24 with rebar in the middle and 6 to 8" thick it will work. Give them at least 2 day to let up, the longer the better.

Why the rebar?
And why in the middle?

 

[Alan]

As long as you make the footings 24 X 24 with rebar in the middle and 6 to 8" thick it will work. Give them at least 2 day to let up, the longer the better.

When you say the middle, you're talking about vertically, right? I'm planning on making them 12" thick, so what depth should I set the rebar at?

 

[joecaption]

12" is way over kill, at that thickness your not going to need any rebar or mesh.
Have you taken the time to see how many bags that's going to take?

 

[BigJim]

Alan, if you are going to jack on the footings I would put a couple of 2X12s with the grain running across each other just for added precautions, it takes concrete a good while to really cure.

 

[Alan]

Alan, if you are going to jack on the footings I would put a couple of 2X12s with the grain running across each other just for added precautions, it takes concrete a good while to really cure.

Thanks Jim.

 

[Alan]

So here is what I found :


The bearing point that I want to jack up does indeed have a footing underneath it. It's a little off center from where it should be, but I don't think that's a huge issue.

I dug down next to the footing, and found that it's thickness is approximately 8" which is pretty much right around 8" below grade. It's also about 16" square with a pier block squished into the top of it probably a couple hours after the concrete for the footing was poured.

In digging, I found that I had to go another 6" below the bottom of that footing to find what seems to be undisturbed soil. There were still a couple of veins of loose soil around the edge of my hole, so I will probably have to excavate another 2-3" of the hard stuff.

How do I know how hard the soil should be to support this footing? I can definitely tell the difference between the loose soil (fill?) and this other stuff at the bottom of my hole.

With that all in mind, I think that I have a good game plan here. Let me know if you don't think this will work.

1 : Dig 18 x 18 hole on either side of the footing in order to allow for cribbing to support jacks.

2 : Install cribbing and jack beam up to desired elevation

3 : Remove post and footing from under beam. (roto-hammer time? :laughing

4 : Dig 24 x 24 hole where existing footing was down to undisturbed soil.

5 : Pour new footing, install brackets, and set post after concrete has cured


I think the only other question I have is : If my footing is that far below grade, won't I have to pour a thicker footing in order to keep my lumber above the dirt? Is there some other way of doing this that's escaping me?


Thanks in advance. P.S. I'm dirty.

 

[BigJim]

Sounds like you got it going your way. I missed somehow where you said what you were jacking up and how far from the floor to the footing it is.

Is where you are going to jack a weight bearing spot or just taking a swag out of your joists?

 

[Alan]

Sounds like you got it going your way. I missed somehow where you said what you were jacking up and how far from the floor to the footing it is.

Is where you are going to jack a weight bearing spot or just taking a swag out of your joists?

It was in another thread... no problems there. I actually only have about 14 " or so from the footing to the bottom of the beam so I need a hole to set the jacks in. No joists, post and beam, tongue and groove 2x6 subfloor.

I was planning on jacking at the weight bearing point but since there is already a post and footing there, I guess the best I can do with it is set a jack on either side of it as close as I can get it?

I need it to move up about 1/2"

 

[joecaption]

The new piers should be concrete block not wood!
#1 That would spread out the load.
#2 No way is it ever going to rot.

 

[BigJim]

Alan, I remember your other thread now. Joe is right, I would come off the footing with concrete blocks, that would keep your wood away from the ground.

 

[Alan]

Joe : Any chance you could do a quick sketch so I can get a visual on what you mean?

Does the rest of my plan seem like it will work out ok?

 

[Alan]

OR : What type of concrete block are we talking about, and how do I attach it to the footing?

 

[joecaption]

Look this over.
http://www.raisedfloorlivingpro.com/gallery.shtml

All you need is morter. All the force is downwards.
DO not use aluminum for the termite shield, copper or vinyl will work.

 

[Alan]

Joe :

Would it be just as good to tie a couple vertical pieces of rebar into the footing and pour a column (say 8x8?) to bring the wood connection above grade?

I've never worked with cinder block and mortar before. I'm already mixing concrete anyway.......


Then i could set a bracket into the top of the column and use that to set a post between the beam and concrete.

 

[Alan]

Ok, so this weekend I accomplished step 1.


Got step 2 started. Put the cribbing in (my holes were deep enough for 6 layers of 2x12) set the jacks on them, put my piece of steel with stops and a small layer of plywood between the jack and the steel plate to hopefully absorb some of the offset of pressure from the dirt not being ENTIRELY level (it's pretty close though)


I actually got somewhere between 1/16 and 1/8" of lift, the old post is now free and flops around by hand.

UNFORTUNATELY the jacks are stuck

Am I not using them properly? Maybe they are too old and worn out? Using a 3 foot long piece of 1/2" galvanized pipe to try and turn them, but the pipe is now bending. Should I be using something else to turn them? Would a piece of rebar the same size as my pipe be better? What else can I do?

I guess my last option is to set some more cribbing up and use a hydraulic jack to lift, and just use the screw jacks to hold the beam in place like jack stands on a car.

 

[jomama45]

12" is way over kill, at that thickness your not going to need any rebar or mesh.
Have you taken the time to see how many bags that's going to take?

Pretty much the most common post pad thickness in new construction and remodeling, at least for the last 30 years or so......................:whistling2::whistling2:

To the OP, try a simple 12 ton hydraulic jack or two, and lift in small amounts over several days. Use the screw jacks for back-up/redundancy/safety.........

 

[Canarywood1]

Joe :

Would it be just as good to tie a couple vertical pieces of rebar into the footing and pour a column (say 8x8?) to bring the wood connection above grade?

I've never worked with cinder block and mortar before. I'm already mixing concrete anyway.......


Then i could set a bracket into the top of the column and use that to set a post between the beam and concrete.

Sounds like a plan,i like it better than CMU's and you would have to fill the cavities of them with mortar or concrete anyway.

 

[Alan]

What size rebar should I be using for this?

:huh: