How can I use a rotary laser level with a building in the way?

[Brian Elfert]

I am looking at possibly building a much larger garage over top of my existing garage. The current garage has eight foot ceilings and the new garage will have 16 foot ceilings. I think the new garage would go over the ridge of my current garage. I want to do this so I don't have to find storage for the stuff in my current garage.

Anyhow, how would I use a rotary laser level to level the new footings with a building in the way? I am told it can be done, but my Google searches have failed me so far.

[Bill McNiel]

Layoff the elevation of the existing footing to "line of sight" stakes. Use as many as required to circumvent obstructions.

[Kevin Jenness]

Use a water level.

[Tom M King]

Any windows?

[Jerome Stanek]

Any windows?

+1 on water level more accurate then laser

[Jim Becker]

You'll need to establish more than one reference point since you can only use line-of sight with a rotary laser. Set one and then set one or two more based on that initial reference.

[Dick Strauss]

Use one laser, make a mark on the corner of the building...move the laser around the corner and align it to the original mark. Now you can project the same level line around a corner.

[Zachary Hoyt]

It sounds to me like the easiest way would be to get a really long grade pole and put the level on the peak of the roof. You'd also need a stepladder that was tall enough for someone to climb up to the line and read it.

[Lawrence Duckworth]

That might sound a little goofy but it's very similar to shooting a DIY topo, once it's set you're pretty much good to go. I've used a 16' 2x4....probably looked a bit stupid walking around in the middle of a pasture with a 2x sticking up in the air though. :)

......You might give it a go and try to put on like you couldn't find a shorter 2x

[Jim Becker]

Using super long grade poles and so forth sounds kewel, but just transfering the reference as both Dick and I have suggested is easy, accurate and stays at ground level.

[Brian Elfert]

I thought a rotary laser level is the way construction is done these days. I bought a good one (At 50% off it was still around $400.) from Amazon Warehouse Deals about two years anticipating my garage project. I didn't do any research into alternatives like the water level.

A water level might still be an alternative and just sell the laser level. It looks like brand new. The included batteries are unopened. I have no idea why it was returned to Amazon.

[Steve Jenkins]

If you use a really long grade pole make sure it’s vertical. If it is tilted either away or towards the laser it can throw you off by inches.

[Ken Fitzgerald]

Brian,

Before retiring, the way we leveled MR scanners, CT scanners and x-ray equipment was using a water level. I helped a guy side his house and we used a water level. At the same time, I have a Bosch non-rotating laser level I use here at home. Water levels work easier if there is more than one person working, using it at the time.

[Jim Becker]

I thought a rotary laser level is the way construction is done these days. I bought a good one (At 50% off it was still around $400.) from Amazon Warehouse Deals about two years anticipating my garage project. I didn't do any research into alternatives like the water level.

A water level might still be an alternative and just sell the laser level. It looks like brand new. The included batteries are unopened. I have no idea why it was returned to Amazon.
Brian, I also bought a rotary laser for my shop project. For me, I feel it's going to be a lot more useful and less cumbersome than a water level. I know a lot of folks prefer a water level and I respect that; I prefer the tech.

[Walter Plummer]

About the grade pole. Lean it forward and backward, the shortest measurement is plumb. Way back in the dark ages when we used a transit or builder's level that is how we did it.

[Scott Winners]

If you can get it done fairly quickly you might be able to use mirrors to " go around." I have only fooled with lasers on tables in a lab, but if you can use mirrors to go around the obstacle clockwise, make a mark; leave the laser fixed, go around the obstacle counterclockwise with mirrors and hit the same mark your done. Bring the laser around the obstacle, line it up to your marks and move on to the next step. Your mirrors need to be lab grade flat and lab grade vertical.

NB: there are often unforeseen problems moving out of the lab into the field. A decent lawyer should be able to explain a water level to a jury in under three minutes. Archaeology field school was many many moons ago for me, but Walter is right about using grade poles (stadia rods), shortest number is the correct number.

[Jerome Stanek]

If you can get it done fairly quickly you might be able to use mirrors to " go around." I have only fooled with lasers on tables in a lab, but if you can use mirrors to go around the obstacle clockwise, make a mark; leave the laser fixed, go around the obstacle counterclockwise with mirrors and hit the same mark your done. Bring the laser around the obstacle, line it up to your marks and move on to the next step. Your mirrors need to be lab grade flat and lab grade vertical.

NB: there are often unforeseen problems moving out of the lab into the field. A decent lawyer should be able to explain a water level to a jury in under three minutes. Archaeology field school was many many moons ago for me, but Walter is right about using grade poles (stadia rods), shortest number is the correct number.

Mirrors can be off by feet if they are not aligned correctly and to align them could take hours.