Leveling with a transit

[merc123]

So I have made a crude transit level and I want to make sure it’s a) going to work and b) I’m doing it correctly.

I have a piece of rebar stuck down into the ground round about center. I put my makeshift transit on it so it spins and keeps the same reference point. It has a level on it and I’m using a laser temp gun for my pointer. I’m using a T-square to measure with.

My process is I put the T-square on the 12x12 block where the leg sits, spin the laser to it and level it. Then read where the laser Is pointing on the square.

My low point appears to be at 15” so I’m digging all the blocks down to meet that 15” mark, which also means I’m at 2-3” in some cases.

 

[Rich D]

Lowering the blocks is the correct idea if the entire area is undisturbed compacted material.
I would question the accuracy of your laser. First at the very least I would suggest a 2' level on top (4' would be best) However even if you can get the level, pipe, laser gun all on a parallel plane I do not think the laser in the gun can be guaranteed to be parallel to the outside casing as this is not what that device is used for. Your best bet to check accuracy might be a water tube level. Another option is if you do have a 4' level is to put the level on a few blocks in the center of the pool and get it perfectly level then run a string just beside the level to 2 posts outside the perimeter of the pool. Use good quality Mason line and stretch it as tight as you can then stretch it a bit tighter. If you start high with your string the easiest way to level it will be to pound the stakes in untill the string is perfectly aligned with the top of level. After confirming the accuracy then you can use your laser for the rest.

If you remove all the plastic from the pool frame your best bet to get all blocks in same plane (not same elevation, that is what the laser is for) is to lay on your belly and simply look over the top of the entire pool frame. You will quickly see any imperfections..

 

[merc123]

So far the laser is getting everything in the same plane. I do the lay down trick and can see the imperfections in the blocks we haven’t lowered yet. We got the pool level by using a 6’ level on top of the frame but it was all sloping you hill. You could see that on your belly and the laser verified it.

I realize the laser probably isn’t calibrated to be parallel to the casing. That’s where the level comes in and the block under my L post. The block doesn’t dig into the dirt, so as long as I get the entire device level it should give me the same point of reference each time. I also don’t turn the laser off between shoots so it’s consistent. The theory seems sound as we have spun it around several times and we reshoot the same blocks and come up with the same measurement.

 

[merc123]

Think we got it. All blocks are level across from each other. Now to level the interior.