Hi,
We bought house a few years ago and now looking at doing some work and had planning approved for a double height extension to replace a conservatory and add an extra bedroom. We were aware of a buried man hole under the conservatory but didn't realise the ramifications of it. Please see picture below:
It is all a private combined sewer (1950's) as we are not connected to anyone else. The first manhole is at top of picture at front of house that takes rain water and waste from downstairs bathroom. This runs to second manhole in garage floor which also takes waste from two upstairs bathrooms. This runs to a manhole buried (brown in picture) under conservatory floor (none of this was us !) with a right angle bend, the bend is cracked although as of yet not caused a problem (accident waiting to happen). This then runs to the third exposed manhole outside property at back which then runs direct to a main sewer line about 5m away.
The approved plans are pretty much on the same conservatory footprint and already as small as would want to go to get a reasonable sized room. The buried manhole is pretty right where the new external wall/foundations would go (it is closer to conservatory wall than in picture)
I have no idea why the previous owners didn't sort this out when the built the double height extension to the side 10 years ago.
From what I have read on building regulations the right angle bend which in itself is not ideal should have a manhole over the top of it. The problem is this would be right where new wall is going and also extending out further and having it inside is not really an option unless we do some weird kink as there is a boundary wall close by. Even if did go further to right (probably a planning re-app) then not too keen on having manhole in what will be new kitchen and would also stop us having units right where they were planned to go.
Only thing I have come up with is to dig a trench from manhole 2 (approx 90cm deep) in garage to manhole 3 (approx 1m deep) outside on a diaganol. Be a bit of a nighmare as garage floor is part of double height extension done 10 years ago so is a really good job. Could I guess lintel it as comes out of old extension and looks like will be far enough away from new foundations not to be a problem. No idea how much doing that would cost to cut into a decent slab to that depth and do all pipework. Would then need to get the rain water from the back to third manhole around the new extension (green dotted line at bottom) with series of right angle bends to avoid new extension completely, this would take the buried manhole completely out of the loop.
Only good news as private don't need to involve Welsh Water for build over agreement and all down to building regs.
Only other thing was if replace right angle bend and try and build a mega inspection chamber under the foundations with access from outside so not directly over the bend but can get to bend - no idea if that is even a thing.
Going to try and get building inspector around this week to discuss and also builder to quote but thought would post as giving me sleepless nights and wandered if missing anything obvious ?
Many thanks,
Lawrence
We bought house a few years ago and now looking at doing some work and had planning approved for a double height extension to replace a conservatory and add an extra bedroom. We were aware of a buried man hole under the conservatory but didn't realise the ramifications of it. Please see picture below:
It is all a private combined sewer (1950's) as we are not connected to anyone else. The first manhole is at top of picture at front of house that takes rain water and waste from downstairs bathroom. This runs to second manhole in garage floor which also takes waste from two upstairs bathrooms. This runs to a manhole buried (brown in picture) under conservatory floor (none of this was us !) with a right angle bend, the bend is cracked although as of yet not caused a problem (accident waiting to happen). This then runs to the third exposed manhole outside property at back which then runs direct to a main sewer line about 5m away.
The approved plans are pretty much on the same conservatory footprint and already as small as would want to go to get a reasonable sized room. The buried manhole is pretty right where the new external wall/foundations would go (it is closer to conservatory wall than in picture)
I have no idea why the previous owners didn't sort this out when the built the double height extension to the side 10 years ago.
From what I have read on building regulations the right angle bend which in itself is not ideal should have a manhole over the top of it. The problem is this would be right where new wall is going and also extending out further and having it inside is not really an option unless we do some weird kink as there is a boundary wall close by. Even if did go further to right (probably a planning re-app) then not too keen on having manhole in what will be new kitchen and would also stop us having units right where they were planned to go.
Only thing I have come up with is to dig a trench from manhole 2 (approx 90cm deep) in garage to manhole 3 (approx 1m deep) outside on a diaganol. Be a bit of a nighmare as garage floor is part of double height extension done 10 years ago so is a really good job. Could I guess lintel it as comes out of old extension and looks like will be far enough away from new foundations not to be a problem. No idea how much doing that would cost to cut into a decent slab to that depth and do all pipework. Would then need to get the rain water from the back to third manhole around the new extension (green dotted line at bottom) with series of right angle bends to avoid new extension completely, this would take the buried manhole completely out of the loop.
Only good news as private don't need to involve Welsh Water for build over agreement and all down to building regs.
Only other thing was if replace right angle bend and try and build a mega inspection chamber under the foundations with access from outside so not directly over the bend but can get to bend - no idea if that is even a thing.
Going to try and get building inspector around this week to discuss and also builder to quote but thought would post as giving me sleepless nights and wandered if missing anything obvious ?
Many thanks,
Lawrence
