user laser level / levelling hose

[garyo]

I have a 1/2" height difference between one end of a 14 metre foundation, and the other. When I say height difference, I mean a difference between the distances from the foundation up to the DPC.

The problem is that my spirit level and laser level tells me the DPC is level, and that each of the 7 runs of foundations are also all level (P-shaped).

I've bridged where I can with a 5 metre piece of timber, and that's also reported as level. I've lost faith in the laser level to be honest, because I get the feeling that the 7 metre distance allows a tiny change in the level to be exaggerated at the other end.

I thought I'd try using a hose pipe / clear tube level to establish whether it's the DPC that's not level, or part of the foundation. I've struggled with this - air locks I think - because the foundations are too deep and the ground between causes high spots. Is there a knack to this? I'm going to try mounting either end of the hose on reference sticks tonight so that the high spots are eliminated.

Gary

 

[^woody^]

12.5mm over 14000mm is well within tolerance for any extension, and any greater accuracy will be hard to achieve with a laser spirit level, spirit level or a piece of timber

 

[garyo]

That's reassuring at least. The actual problem I have is that I want the brickwork/mortar courses to line up at the start and finish, so I guess I'll make up the difference and feather it back in over, say, 7 metres of foundation.

The conservatory base plans quote triangulation dimensions from the two setting out points down to the millimeter, and am not really sure what the acceptable tollerance is for them.

Gary

 

[^woody^]

Brickwork lines are not pencil lines, and no one builds to the millimeter.

You should ideally set up some frames and gauge down, alternatively set up the levels for the cill heights on some profiles and gauge down from them.

Never gauge up if you can avoid it.

And any slight discrepancies in the brickwork are allowed for when the frames are fixed

For setting out corners, you should get hold of the pre-made cill if possible and set out to this. If not available, 10-15mm tolerance will be OK, and can be taken up by the cill overhang if needed

 

[The-brickie]

Agree with woody there, 10-15mm is nothing in size and if your gauging down from dpc and you want it run courses, set a datum at DPC and put lever pegs in near each corner, work down to top of concrete and put in a split course if needed but make sure its all level at dpc.

I would avoid the welded cill mind because they can be out due to the weld discrepancies, build to base plan layout and dont worry to much about the odd mm here and there, just make sure its all square.