LA3222 Posted August 6, 2019 Share Posted August 6, 2019 Afternoon all, I'm hoping the collective wisdom in the forum can look at my drainage plan and tell me if it needs/how to improve it! It's something I keep coming back to, but as much as I stare at it I don't think it's optimal. On the ground floor there are two foul runs coming out to the same IC, not sure why it was drawn like that but surely they can be combined. TIA for any feedback. Link to comment Share on other sites More sharing options...
Carrerahill Posted August 6, 2019 Share Posted August 6, 2019 The two which combine externally at the IC, one for upstairs, one for the downstairs WC. I would personally not want to have the first floor soil share a stack with the ground floor WC - blockage could result in a nice poo fountain. It is not going to take much to have them separate. Utility and bed 4 en-suite also combine, albeit internally. I guess you could tie the ground floor WC into the stack in the wall by coming out the toilet and going 90° into that stack. But it wouldn't be me. I have actually just done some new waste and soil pipe for my extension and I have got the kitchen on it's own waste and not tied it into the soil pipe which runs right down through the wall about 2m from the new sink location. I always split them. I wonder if optimal is the correct term - I get the impression you may be trying to value engineer it - which often results in less robust design. I wouldn't want the stack going through my dining room/living room wall - you will hear it - I would either use Marley dBlue or move it. Link to comment Share on other sites More sharing options...
epsilonGreedy Posted August 6, 2019 Share Posted August 6, 2019 28 minutes ago, LA3222 said: It's something I keep coming back to, but as much as I stare at it I don't think it's optimal. Three ICs for 4 bathrooms, kitchen, util and WC looks very efficient to me. Mine got complicated because (1) it is an l-shaped house (2) I decided to save £2000 by sharing the sewer with a neighbour when meant an inconvenient main drain approach angle, then (3) we decided the rear door into the utility area would in fact be our principal entrance hence we moved the utility function out to the garage. Link to comment Share on other sites More sharing options...
PeterW Posted August 6, 2019 Share Posted August 6, 2019 12 minutes ago, epsilonGreedy said: Three ICs for 4 bathrooms, kitchen, util and WC looks very efficient to me. An IC has 5 inlets - you could do this with 2 ICs comfortably. This needs a bit of thought but you can remove a lot of things in this design. Link to comment Share on other sites More sharing options...
epsilonGreedy Posted August 6, 2019 Share Posted August 6, 2019 3 hours ago, PeterW said: An IC has 5 inlets - you could do this with 2 ICs comfortably. This needs a bit of thought but you can remove a lot of things in this design. I thought 3 inlets were the norm. What would motivate such a change? The plastic bits of an IC cost < £100. A dynrod callout is £60 minimum. Fewer ICs but longer trenches could end up costing more to implement. Your suggested changes to my plan were an example of excellent lateral thinking and a more efficient plan overall but in the example in this thread is it not close to ideal? Link to comment Share on other sites More sharing options...
PeterW Posted August 6, 2019 Share Posted August 6, 2019 I pay £68 for a 5 inlet 450mm IC with 2 risers. Unless pushed I wouldn’t use a 300mm IC as they are too tight to rod. Long straight runs are the key - putting connections such as dishwashers and washing machines on the end of runs along with kitchen sinks means your “slow flows” will get plenty of volume. Link to comment Share on other sites More sharing options...
LA3222 Posted August 6, 2019 Author Share Posted August 6, 2019 6 hours ago, Carrerahill said: I would personally not want to have the first floor soil share a stack with the ground floor WC - blockage could result in a nice poo fountain. Fair point, each WC has its own soil stack as things stand, now you point it out I can see the benefit. I think grey water going into them can only be a good thing though - to keep things moving? 6 hours ago, Carrerahill said: I wouldn't want the stack going through my dining room/living room wall - you will hear it - I would either use Marley dBlue or move it. I cant move it so will have to reduce noise, i dont envisage it being an issue, its an ensuite so intermittent usage. I'd never heard of Marley dBlue so cheers for the steer. 6 hours ago, epsilonGreedy said: Three ICs for 4 bathrooms, kitchen, util and WC looks very efficient. I'm trying to keep them to a minimum as they are ugly things at best! 1 hour ago, PeterW said: Long straight runs are the key - putting connections such as dishwashers and washing machines on the end of runs along with kitchen sinks means your “slow flows” will get plenty of volume. This is why i like having grey water from upstairs feeding into each of the stacks. It may be, from the feedback that the layout is a reasonable one. I will stew on this for a while longer before going firm on It! Ta Link to comment Share on other sites More sharing options...
PeterW Posted August 6, 2019 Share Posted August 6, 2019 Too many vertical stacks in that. Flip the en-suite in the master round and they can share a stack with the main bathroom (which doesn’t have a WC..??) and then the kitchen waste and cloaks can feed into that too. En-suite 3 needs a rework as turning a WC fed horizontal soil 90 degrees is asking for trouble. Move the WC and the shower, put the WC as close the the stack as possible. Can probably get this to 3 stacks and a couple of ICs without too much hassle. Link to comment Share on other sites More sharing options...
Carrerahill Posted August 7, 2019 Share Posted August 7, 2019 11 hours ago, LA3222 said: Fair point, each WC has its own soil stack as things stand, now you point it out I can see the benefit. I think grey water going into them can only be a good thing though - to keep things moving? I cant move it so will have to reduce noise, i dont envisage it being an issue, its an ensuite so intermittent usage. I'd never heard of Marley dBlue so cheers for the steer. I'm trying to keep them to a minimum as they are ugly things at best! This is why i like having grey water from upstairs feeding into each of the stacks. It may be, from the feedback that the layout is a reasonable one. I will stew on this for a while longer before going firm on It! Ta Grey Water into soil - yes - I do this too. I think a shower or bath down a soil pipe is a good idea. dBlue is good stuff, a little pricey but you don't need much, it removes the splat splash tinkle noise from your wall. Link to comment Share on other sites More sharing options...
LA3222 Posted August 7, 2019 Author Share Posted August 7, 2019 14 hours ago, PeterW said: Flip the en-suite in the master round and they can share a stack with the main bathroom (which doesn’t have a WC..??) and then the kitchen waste and cloaks can feed into that too. This makes sense. Correct about no WC in main bathroom - personal preference. 14 hours ago, PeterW said: En-suite 3 needs a rework as turning a WC fed horizontal soil 90 degrees is asking for trouble. Move the WC and the shower, put the WC as close the the stack as possible. Makes sense. So I think that brings me to 3 soil stacks with the bathroom one serving two toilets two showers and two sinks. Link to comment Share on other sites More sharing options...
Oz07 Posted August 7, 2019 Share Posted August 7, 2019 Would it always be preferable to have grey water into a run if it needs an inaccessible junction below slab. I've got a couple of loos that can either be at end of run or y branch under slab with extension to kitchen/ washing machine. Does underground y junction mean rodding access both ends is more important? Link to comment Share on other sites More sharing options...
epsilonGreedy Posted August 8, 2019 Share Posted August 8, 2019 12 hours ago, Oz07 said: Does underground y junction mean rodding access both ends is more important? NHBC have a published standard for this situation and require a rodding point at the end of each branch. Link to comment Share on other sites More sharing options...
PeterW Posted August 8, 2019 Share Posted August 8, 2019 1 minute ago, epsilonGreedy said: NHBC have a published standard for this situation and require a rodding point at the end of each branch. And they never enforce it ..!!! I snagged a new NHBC warrantied property that had 4 soil stacks - 3 through the roof - and a single IC in the centre of the drive. No rodding points or access to any of the stacks. Best practice is rodding points but unless you design the connections correctly it is irrelevant. Link to comment Share on other sites More sharing options...
epsilonGreedy Posted August 8, 2019 Share Posted August 8, 2019 1 minute ago, PeterW said: Best practice is rodding points but unless you design the connections correctly it is irrelevant. A typo? Did you mean "incorrectly"? Link to comment Share on other sites More sharing options...
PeterW Posted August 8, 2019 Share Posted August 8, 2019 No I mean correctly. If you have a branch and stack, and a run out of the founds to a rodding point on the main run but have a 87.5 degree join or put elbows between the rest bend and the main run, you will slow the flow down in the branch before it meets the main run, so a rodding point is irrelevant as it will never be able to reach the blockage. Issues occur when bends are placed too close to rest bends, or elbows are used where a pair of 45 degree bends would be better. You can buy “slow bends” for use underground, sometimes called large radius bends. If you have to change direction by 90 degrees then consider one of these over shorter bends. Link to comment Share on other sites More sharing options...
Oz07 Posted August 8, 2019 Share Posted August 8, 2019 (edited) 6 hours ago, epsilonGreedy said: NHBC have a published standard for this situation and require a rodding point at the end of each branch. Does that mean your better off with single runs and rodable from downstream rather than branched connection? means you lose the grey water flow. 6 hours ago, PeterW said: No I mean correctly. If you have a branch and stack, and a run out of the founds to a rodding point on the main run but have a 87.5 degree join or put elbows between the rest bend and the main run, you will slow the flow down in the branch before it meets the main run, so a rodding point is irrelevant as it will never be able to reach the blockage. Issues occur when bends are placed too close to rest bends, or elbows are used where a pair of 45 degree bends would be better. You can buy “slow bends” for use underground, sometimes called large radius bends. If you have to change direction by 90 degrees then consider one of these over shorter bends. I thought you meant incorrectly too. Trying to get head around what you're saying I've got loads of them Long radius bends can either be used as a rest bend or horizontally with the top cut off for 90deg IC, then risers concreted ontop, also as you say underground 90 bends. I've only ever used them for underground 90 bends between 2 IC's though, however never had a blockage there. Edited August 8, 2019 by Oz07 Link to comment Share on other sites More sharing options...
PeterW Posted August 8, 2019 Share Posted August 8, 2019 Probably worth clarifying Don’t use these underground to change direction unless you have to Use these If you have a 45 degree entry to an IC and have to come in at 90 degrees to it, a 45 around 400 to 600mm away from the IC is preferable in case you need to rod as if they are too close together you can jam the rods. 1 Link to comment Share on other sites More sharing options...
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