Breaking up poured concrete near foul drain and waste gully

[dannyrico]

Early 1900's Victorian property with poured concrete at the side. I plan to get rid of the whole thing because 1) aesthetic choice, but more importantly 2) it's bridging DPC (if there even is one...) and causing damp issues. I'd rather take it all up than cut a channel.

I don't know when the concrete was added, but it looks to me like they poured around cast iron foul drain pipe and added a waste gully to perhaps tie in somehow.

What's my best path forward to avoid damaging any plumbing that is below this concrete?

 

[polesapart]

Lifting the lid of the nearest downstream inspection chamber should give a good indication of route and depth of drain.

 

[Hugh Jaleak]

Work carefully and methodically, once you've got started and can get underneath, it may be possible to lever up the next section slightly with a long bar and then break it from above. I'd also be extremely cautious around that Gas Service, there is not telling how deep that'll be, have uncovered them before literally just under the concrete!

That mortar 'skirting' along the bottom of the wall may not be helping, if you can remove that I would and a couple or three coats of bitumen paint at least up to DPC level, (if you can find one!), may help too.

 

[Madrab]

Do you have a wooden suspended floor? If so then the airbricks in the top wall would be there to ventilate that space. If that the case then the DPC may be above them and just below the level of the joists. Given the age of the property, it's probably on the cusp of either having or not having a slate DPC added but that would usually be quite visible.

As @Hugh Jaleak suggests, start slowly at either entry point - downpipe or gulley till you know the depth & direction, then start at the top and take your time and then follow the pipework ... and definitely be careful around the gas supply, it's pretty apparent where that's been run but they never seem to follow any standard re depth and if that crete is newer then it may be harder to crack, coming in the from either side rather than top down may be easier.