I have a clay drain run that crosses perpendicular to my foundation. The invert of the pipe is 50mm higher than the bottom of the foundation. Is it acceptable to box this in with 22mm OSB, fill with pea shingle, then mass-fill over the top without lintelling, or should I position some rebar lengths or PSC lintels over the top before mass filling? I expect the span would end up being ~300mm.
I don't particularly want to shutter all the way to the top of the foundation for fear of it leading to a weakness in the run that might lead to brickwork cracks through differential settlement of either side of the foundation.
Thanks
I don't particularly want to shutter all the way to the top of the foundation for fear of it leading to a weakness in the run that might lead to brickwork cracks through differential settlement of either side of the foundation.
Thanks