Vijay Posted March 4, 2017 Share Posted March 4, 2017 Is there a minimum that the drainage/waste pipes need to be under external finished ground level? I need to look at the drainage points and work out falls. Is between 1 in 40 and 1 in 110 for falls right? Cheers Vijay Link to comment Share on other sites More sharing options...
jamiehamy Posted March 4, 2017 Share Posted March 4, 2017 I generally went for between 1/80 and 1/40 (depending on area as we couldn't go down further). Wouldn't go less than 1/80 tho - maybe just a bit too shallow. Link to comment Share on other sites More sharing options...
PeterW Posted March 4, 2017 Share Posted March 4, 2017 1:80 to 1:40 is the recognized limits for underground with 1:100 being a real exception usually used on internal soil runs if you can't get the falls. Ideally you want 250mm coverage on the pipes but on sloping ground that can be a challenge so look at using a couple of chambers with back drops to get some depth. Link to comment Share on other sites More sharing options...
ProDave Posted March 4, 2017 Share Posted March 4, 2017 I have always found it easier to start at the destination (entry to treatment plant for example) which will usually have a fixed depth, and then work that backwards towards the house, and see what sort of sensible fall you can achieve without the pipe getting too close to the surface. 1 Link to comment Share on other sites More sharing options...
joe90 Posted March 4, 2017 Share Posted March 4, 2017 (edited) It depends on what is happening on the ground, I.e. Garden, path, drive etc. It's all here, happy bed time reading ( I know because I had to read it all). https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/442889/BR_PDF_AD_H_2015.pdf because I was limited to the depth i could go, I started at the shallowest pipe ( garage toilet) and worked my way downhill, I just hope by the time I get to the treatment outfall I am ok, if not I will have to have a pumped solution ? Edited March 4, 2017 by joe90 Add Link to comment Share on other sites More sharing options...
Vijay Posted March 17, 2017 Author Share Posted March 17, 2017 Measure the main drain run that the developers install which looked to be 6" pipework, it's a 1:90 fall Link to comment Share on other sites More sharing options...
Vijay Posted March 20, 2017 Author Share Posted March 20, 2017 Would running a 10m+ pipe run under the house be a stupid idea? A friend made the point of you could never replace it if you ever needed to Link to comment Share on other sites More sharing options...
PeterW Posted March 20, 2017 Share Posted March 20, 2017 5 minutes ago, Vijay said: Would running a 10m+ pipe run under the house be a stupid idea? A friend made the point of you could never replace it if you ever needed to Plenty do - and a properly laid pipe with lintels or movement joints as it passes over the founds should mean it's fine for decades. UPVC is inert and underground it has none of the problems of sunlight etc. degrading the plastic. Is it shown on the plans ..?? And if you've got B&B floors then there will be no impact or loading on the pipes. Link to comment Share on other sites More sharing options...
Vijay Posted March 20, 2017 Author Share Posted March 20, 2017 (edited) No, the pipes are run around the house but I always thought that it would be a shame to have manholes/rodding points showing in the rear outside area. This is the service plan which I've shown the manhole locations in red dots. As you can see it doesn't make sense not to utilise the manhole at the bottom (of the page). Drainage points are the blue dots Edited March 20, 2017 by Vijay Link to comment Share on other sites More sharing options...
Nickfromwales Posted March 20, 2017 Share Posted March 20, 2017 Laser and a yardstick and you'll know to the mm in minutes . Link to comment Share on other sites More sharing options...
Oz07 Posted March 20, 2017 Share Posted March 20, 2017 I'd rather have ic's and ridding points than not have them and need them! You know you can use the lids which can be paved Link to comment Share on other sites More sharing options...
Vijay Posted March 20, 2017 Author Share Posted March 20, 2017 16 minutes ago, Nickfromwales said: Laser and a yardstick and you'll know to the mm in minutes . Hey Nick. Know what, the falls? Link to comment Share on other sites More sharing options...
Vijay Posted March 20, 2017 Author Share Posted March 20, 2017 12 minutes ago, Oz07 said: I'd rather have ic's and ridding points than not have them and need them! You know you can use the lids which can be paved Yeah I know you can get the paved ones but you can obviously still see they're there. Just looking for alternative solutions, but I completely understand your point of having them, cos if there's a blockage, I'd curse myself if I didn't Link to comment Share on other sites More sharing options...
Nickfromwales Posted March 20, 2017 Share Posted March 20, 2017 34 minutes ago, Vijay said: Hey Nick. Know what, the falls? Sorry, yes. No need to guess if things will line up that way, and you can then squeeze max fall out over the distance . Link to comment Share on other sites More sharing options...
Vijay Posted March 23, 2017 Author Share Posted March 23, 2017 Don't know if this is a stupid question but can chambers be stacked up so you get more than 4 (or possibly 5 if it's the last one) inlets? Link to comment Share on other sites More sharing options...
Nickfromwales Posted March 23, 2017 Share Posted March 23, 2017 Yes. Just put two in line with each other or a smaller chamber to take 2 into one before getting to the larger chamber. Link to comment Share on other sites More sharing options...
Vijay Posted March 23, 2017 Author Share Posted March 23, 2017 Sorry Nick, I meant can they be stacked vertically? In line would then have 2 manhole covers surely? Link to comment Share on other sites More sharing options...
PeterW Posted March 23, 2017 Share Posted March 23, 2017 Best practice is not to try and have large numbers of flows into a single IC especially if the main branch is only 110mm. What @Nickfromwales is suggesting is correct - you would use 2 or 3 smaller (ie 300mm) ICs to collate the flow from say 2 WCs or stacks, and then feed them to a further IC later in the chain, with a single 110mm (or 160mm if flow dictates) leaving the property. Do you have an M&E plan for the build as if you are looking at multiple WCs then be mindful of Part H and the various depths and falls required. Link to comment Share on other sites More sharing options...
Nickfromwales Posted March 23, 2017 Share Posted March 23, 2017 1 hour ago, Vijay said: Sorry Nick, I meant can they be stacked vertically? In line would then have 2 manhole covers surely? You can make a 'back drop' chamber but it's a bit yesteryear. I'd just combine flows with smaller local ICs and then join the main run larger IC accordingly. Maybe best to run this past your BCO TBH rather than just steaming ahead . Link to comment Share on other sites More sharing options...
Vijay Posted March 23, 2017 Author Share Posted March 23, 2017 3 hours ago, Nickfromwales said: You can make a 'back drop' chamber but it's a bit yesteryear. I'd just combine flows with smaller local ICs and then join the main run larger IC accordingly. Maybe best to run this past your BCO TBH rather than just steaming ahead . Understood, I will go inline but check with the BCO before I do anything Link to comment Share on other sites More sharing options...
Vijay Posted March 23, 2017 Author Share Posted March 23, 2017 3 hours ago, PeterW said: Best practice is not to try and have large numbers of flows into a single IC especially if the main branch is only 110mm. What @Nickfromwales is suggesting is correct - you would use 2 or 3 smaller (ie 300mm) ICs to collate the flow from say 2 WCs or stacks, and then feed them to a further IC later in the chain, with a single 110mm (or 160mm if flow dictates) leaving the property. Do you have an M&E plan for the build as if you are looking at multiple WCs then be mindful of Part H and the various depths and falls required. The main pipework looks to be 160mm that runs through the plots with a 1:90 fall. I will definitely look at having IC's inline once I get my head around a layout. The fact I've never heard of an M&E plan would suggest not. What is it?? Link to comment Share on other sites More sharing options...
Vijay Posted April 6, 2017 Author Share Posted April 6, 2017 (edited) If I wanted to run the kitchen waste to the nearest manhole, there's a 17m run. FFL to the bottom of the manhole inlet is approx 1085mm but a 1:40 fall in the pipework would only need a 425mm drop, would a backdrop manhole be the only way to do that? Or do I drop it down at the start of the run and have the pipe going through the foundations? I've asked a couple of builder mates and had different responses - but they don't do new builds................................. Edited April 6, 2017 by Vijay Link to comment Share on other sites More sharing options...
PeterW Posted April 6, 2017 Share Posted April 6, 2017 You work back from the IC - so in that case the IC is 1085 and you would need an invert depth of 660 next to the slab. If FFL is 150mm above slab then that's only 410 which is not much more than a rest bend and 120mm of pipe in it Link to comment Share on other sites More sharing options...
Vijay Posted April 6, 2017 Author Share Posted April 6, 2017 (edited) If I understand that correctly, that would mean the drainage pipe running through the foundation, is that OK to do? And it's beam and block rather than a slab Edited April 6, 2017 by Vijay Link to comment Share on other sites More sharing options...
PeterW Posted April 6, 2017 Share Posted April 6, 2017 It is if you sleeve it or do the detail properly... what depth are the top of your foundations below finished ground level ..? Link to comment Share on other sites More sharing options...
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