New extension brickwork, 30mm diff. Existing wall heights

[Bob a job]

I am self building a rear extension and the foundation was poured level using laser levels 375mm below dpc. It seems that although the concrete block on one end wall lines up nicely, the other external wall is 30mm higher so the block is 30mm too low. Do I just have to presume my blocks/bricks will never line up on one side of the extension where it joins the existing house or should I build it slightly off level?

New build will be block and beam flooring, current planned makeup of brickwork would be for inner skin one block then block and beam floor, outer skin a block to reach ground level and 2 bricks to dpc.

Thanks in advance

 

[theprinceofdarkness]

If you can get the internal doorways not to have a step, then follow the existing mortar courses. My bungalow was build as a single ridge building, it has had two extensions built at at each end to make it a U shape. So I came along to fill the U in with a conservatory. The floor levels from side to side were out by 30mm so one door into it has a small step. The two sides of the U had a 30 mm splay which was taken up in the shape of the conservatory.
Frank

 

[^woody^]

You need to guage down from the wall plate or frame heads, not just measure the level at DPC.

Generally you should build level, or it shows up on the corners, frames or fascia etc, and looks crap. If need be, split any difference in level on the main house, by adjusting the extension corners up or down.