Water level / laser

[23vc]

Hi guys
I need to set out the corner levels to build up to dpc level for my extension, it's 2x 10m walls and 2x 2m returns.
I know a rotating laser is the way a lot of Pro's do it but seeing as I don't do this every day (or ever again lol) I was tempted to use a water level. I'd plan on pegging near the corners and marking the pegs level, then getting the block corners to the marked height.
I'd really appreciate any opinions of whether I've got any chance of getting this level enough with a water level or if I'm just being tight and should hire a rotating laser (also I wasn't sure if the 10m+ distances are OK for either method)
Cheers
John

 

[r896neo]

A water level is totally fine. Just do the whole operation twice to make sure its correct.

 

[23vc]

Lovely, thanks

 

[John D v2.0]

Surely a water level would be more accurate, although more FAFF. Laser levels have cumulative (well, percentage really) error but water levels only have a certain error, so the further you go the better a water level is!

 

[r896neo]

The benefit of a water level is you don't need line of sight so can go round corners etc. The problem with them is marking accurately. A laser and staff is very accurate because you are not marking a pencil line etc so there I little margin for error plus getting the water totally still and at the right level is a pain.

 

[John D v2.0]

Good point about going round corners! I used a laser to do my sockets and it was great because I set it up and then just wandered around making them all up. Using a water level I'd have given up by then! But if you're going a long way and round a corner a laser would be a bit a liability without rigging up some temporary marker posts.

 

[r896neo]

Just to be clear for anyone else reading this I am talking about an external self levelling rotary laser like a topcon or similar.

There is a huge difference in a rotating line laser for levelling sockets etc and a proper outdoor rotary laser used with a receiver. The accuracy difference is massive and a rotating line type level is not a good choice for accurate measurements over long distance like setting out buildings sites etc.

 

[23vc]

Thanks, yeah that was my understanding and I've now got a water level. Thanks.

 

[stuart45]

Have you used a water level before?

 

[23vc]

No

 

[stuart45]

Pretty simple to use, especially if you have a helper.
Fill the tube so the level is at 0 on both gauges and no air in the tube.
Get your help to hold the 0 to the datum mark and take the top off.
Take yours to roughly the level where you want make the mark and release the cap and put your thumb quickly over the top.
Take your thumb off a bit and watch the level. If it moves put your thumb back or water may shoot out from one end.
Move your end either up or down and try again until the water stays still at the 0.

 

[23vc]

Thanks Stuart I really appreciate the info

 

[stuart45]

No prob,
one more small tip, if setting a level close to the ground it can be easier to knock in longer pegs and measure a mark say 2 ft above the datum and then measure down on the pegs from the marks. In houses datum marks were made 3ft or later 1 metre above FFL for the screed etc when using a water level.