Drainage advice please

[WWilts]

Which professional would you entrust with the design of foul drainage? (architect / engineer / other) Assume nobody in the family is in a position to self-design

 

This is a self-build in our rear garden, located to the north of our house. The mains sewer is located nr south east corner of our front garden. Land slopes gently down to the rear (north), height difference in ground levels roughly 2 m from rear of new build to main road.

 

Architect has drawn nearly all of the remaining Bldg Regs stuff but has so far avoided committing to any firm foul drainage plan. Saying builders will have good suggestions. So foul drainage is in limbo at present. I'd prefer to get builder (main contractor) quotes for a fully specified build.

Grateful for any advice.
 

[PeterW]

Main bathroom run is going to be a nightmare. I’m assuming you don’t want any external soil stack showing on this new build ..??

 

 

[WWilts]

Open to any possibility. No strong views, given my ignorance.

But main question is

To which professional shoudl I entrust the drainage design (& specs for Building Regs)? Architect / engineer / other?
Context on Building Regs permission: Likely Going for single building notice and private Building Control.

[SuperJohnG]

1 hour ago, PeterW said:

Main bathroom run is going to be a nightmare. I’m assuming you don’t want any external soil stack showing on this new build ..??

 

 

How come? 

[Dave Jones]

Plumber will do the above ground , builder/groundworker will do below ground.

 

You don’t really want external soil stack as it looks gash so some thought and planning of where you bring it through the house into the ground is needed. 
 

sewer pipe is wider than a stud wall remember, but with pozi joists can help routing them no end.

Edited January 19, 2021 by Dave Jones

[Dave Jones]

I’d also ditch the pull cords in bathrooms , architect still thinks it’s 1970 lol 

 

don’t get the communal en-suite either split them off , who wants to share a sink with another bedroom ! Odd.

 

the bedroom windows have non climbing guards, are they not fire escape windows ?

 

shower in the second downstairs toilet ??? or are you thinking it’s another bedroom off the kitchen as you already have a downstairs toilet by front door ?

6 toilets for a 4 bed is a lot !

 

not seeing any extract ducting to the wc’s , building control will want that.

Edited January 19, 2021 by Dave Jones

[nod]

You will give your groundwork’s a detailed drawing Usually done by the Architect or engineer He will take one look at it then shuv it in his pocket and do his own external design 

[PeterW]

7 hours ago, WWilts said:

Likely Going for single building notice and private Building Control.

Never seen a house built on a building notice and very much doubt you will find a company that will do it. The opportunity for finding a 5 figure issue at inspection would be huge. 

[PeterW]

7 hours ago, SuperJohnG said:

How come? 

the WC is above the largest open void and unless you go to the north wall - so go in reverse and put a fairly nasty external soil stack - you can’t get it easily to the East wall where the majority of other WC connections need to be. Depth of the floor would have to be pretty deep to get drops, and if floor joists run east west it will be around 150mm drop across that run and it still then has to do a dog leg unless you do a run of soil stacks along the East wall which isn’t ideal. 
 

one option would be to box out the end of the wall where the bifold stops in the edge of the kitchen and use that as a stack and put plenty of sound insulation around it so immediately to the left of the WC there would be a vertical stack. 
 

I’d flip the downstairs study WC and shower too and put the WC against the wall as you can also then box in to pick up the Jack and Jill on the same stack. Similar with the front cloaks, switch it left to right and you’ve got a chance of picking up a stack in the bottom right corner of that room. 
 

7 hours ago, WWilts said:

To which professional shoudl I entrust the drainage design (& specs for Building Regs)? Architect / engineer / other?

Who’s doing all your plumbing design ..? Ventilation ..? Decent M&E designer should see that off in a couple of days or so with a full set of plans and elevations and the site plan. 

[Jilly]

My architect's technician gave two drainage options on the plan but said the builder on the ground would make the final decision as he should have experience.

 

I think you would be badly advised to do this on a Building Notice. On a Full Plans application they check everything in advance and confirm you are in the clear. The last thing you want is for them to say near completion that they want something changed or that the regs have altered. 

 

I found this part tricky as they wanted me to chose stuff way before I was ready so they (BC) allowed a few things to be conditional.

 

Also get the design stage SAP calculations done on this so that you are certain that is ok. 

 

I have made changes during the build but only improvements, (ie triple glazing and more insulation) so they have been happy. 

[ToughButterCup]

2 hours ago, nod said:

You will give your groundwork’s a detailed drawing Usually done by the Architect or engineer He will take one look at it then shuv it in his pocket and do his own external design 

 

Add to Gary's ( @nod )  wise view : think about the problem for yourself too - how for example anyone going to repair / clean / clear the drain run? Will the groundworker  take  responsibility for an inadequate design ( PPI ?). Run the design past your plumber too.

 

To answer your question directly

10 hours ago, WWilts said:

Which professional would you entrust with the design of foul drainage? ... Architect has drawn nearly all of the remaining Bldg Regs stuff but has so far avoided committing to any firm foul drainage plan. Saying builders will have good suggestions.

...

 

None. Because everyone is shoving responsibility to everyone else. And that pisses me off. Exactly what everyone tried to do to us.  'King lazy if you ask me. Because everyone's final answer is

 

"Well its up to you mate"

So, ask everyone, pay no-one for the design because nobody is going to commit - unless they do commit of course. 

Can you tell I'm cross about the issue for you?  Good because it happened to us.

 

Why? Because its about the soft  and smelly stuff. And thus to be avoided as far as self-build is concerned. A large house builder would not stand for it. 

Gather a range of views and spend a bit of time researching the subject for yourself. BH is a great place to get a good range of views.

 

The key question is - what happens when (not if) there's a blockage.

 

[WWilts]

3 hours ago, Dave Jones said:

Plumber will do the above ground , builder/groundworker will do below ground.

It's the design stage that troubles me. Currently being left for later by architect. I am not comfortable with that. Even alternatives would seem preferable to no design at all. For pricing by potential main contractor, and for Building Regs.
 

3 hours ago, Dave Jones said:

I’d also ditch the pull cords in bathrooms

I should know all this, but what is the alternative please? Switch outside the door? No views here, genuine complete ignorance. Hence hunger for alternatives to problem situations.
 

3 hours ago, Dave Jones said:

the bedroom windows have non climbing guards, are they not fire escape windows ?

Will ask architect
 

3 hours ago, Dave Jones said:

not seeing any extract ducting to the wc’s , building control will want that.

Tks, will ask architect
 

2 hours ago, nod said:

You will give your groundwork’s a detailed drawing Usually done by the Architect or engineer

No drawing at all, currently. This is my problem

 

58 minutes ago, PeterW said:

Never seen a house built on a building notice and very much doubt you will find a company that will do it. The opportunity for finding a 5 figure issue at inspection would be huge. 

Architect has had them done before, I am told, using builders and private Bldg Inspectors he regularly works with. But I am open to alternatives.
Architect certificate might not suffice for potential buyers if we have to move in a few years (as probable). Inclined to pay for structural warranty in addition. Another whole topic though.
 

1 hour ago, PeterW said:

one option would be to box out the end of the wall where the bifold stops in the edge of the kitchen and use that as a stack and put plenty of sound insulation around it

I like that idea. We had innumerable iterations within the family and had to enforce a design freeze at some point to allow drawings to progress
 

1 hour ago, PeterW said:

I’d flip the downstairs study WC and shower too and put the WC against the wall as you can also then box in to pick up the Jack and Jill on the same stack.

Great idea

1 hour ago, PeterW said:

Similar with the front cloaks, switch it left to right and you’ve got a chance of picking up a stack in the bottom right corner of that room. 

first floor or ground floor? Sorry to be unfamiliar with some of the terminology

 

1 hour ago, PeterW said:

Who’s doing all your plumbing design ..? Ventilation ..? Decent M&E designer should see that off in a couple of days or so with a full set of plans and elevations and the site plan. 

Thanks. Any recommendations for such a M&E designer pls, anyone? 
Recommendation for drainage design (ground works, routing) is what I really need.
See alternative routes 1 and 2 in diagram, next post. 
 

1 hour ago, Jilly said:

I think you would be badly advised to do this on a Building Notice. On a Full Plans application they check everything in advance and confirm you are in the clear. The last thing you want is for them to say near completion that they want something changed or that the regs have altered. 

Sage advice, thanks
 

1 hour ago, Jilly said:

Also get the design stage SAP calculations done on this so that you are certain that is ok. 

Thanks
 

25 minutes ago, ToughButterCup said:

everyone is shoving responsibility to everyone else

It's like going to a surgeon and them saying ask the nurse which operation you need. So the patient needs to google. I'm looking for which surgeon to pin down and make responsible. Paying for design, drawings too. But omissions trouble me

Thanks, I might start sleeping better at night as the concerns get sorted out one by one

[WWilts]

Alternative routes for drainage. My layperson ideas.
Which would you prefer? 1 or 2?
Why?

[PeterW]

35 minutes ago, WWilts said:

Architect has had them done before, I am told, using builders and private Bldg Inspectors he regularly works with. But I am open to alternatives.

The cost for application is the same. And it makes you plan stuff such as all the points I have called out such as pipework that cannot be installed due to steels or joists the wrong way round. 

[PeterW]

34 minutes ago, WWilts said:

Alternative routes for drainage. My layperson ideas.
Which would you prefer? 1 or 2?
Why?

You can’t do 1 without getting permission from your sewage provider as the section from existing to the road becomes an adopted sewer as it services more than one property. 
 

Option 2 requires an easement in property ones deeds so has a cost.  

[ProDave]

Have you looked at levels yet?

 

Regardless of which route you take, it looks to me like the new house is lower down the slope than the road.  Depending on how deep the sewer is in the road, you might very well need a holding tank and pumping station.

[WWilts]

2 minutes ago, ProDave said:

ou might very well need a holding tank and pumping station.

Yes, that is intended

15 minutes ago, PeterW said:

Option 2 requires an easement in property ones deeds so has a cost.  

Won't both options require similar agreements with the host dwelling (us)?

[WWilts]

16 minutes ago, PeterW said:

You can’t do 1 without getting permission from your sewage provider as the section from existing to the road becomes an adopted sewer

Ancient private drain and manhole there. So option 1 would have the drain running along the east boundary to join the main sewer directly. 

[CivilEng2020]

Above ground drainage by a plumber/architect and below ground drainage by a drainage consultant.

Edited January 22, 2021 by CivilEng2020

[WWilts]

Anyone used Drainstore packaged sewage pumping station? (packaged pumping chamber)

 

Any good or bad experiences? Any recommendations for or against any make of pumping station?

[saveasteading]

Check out the relative cost of a sewage treatment package. 

The cost of a pump system can be surprisingly high, mostly because they have a large capacity in case of breakdown or power-cut..

Plus, usually a spare motor in it. 

Then there is a lot of pipe. This is small dia, flexible and easy but is going through other land and the connection can be tricky.

And you have power to the pump.

thousands.

 

whereas a package treatment system is near to the house, and all yours.

PLUS you don't pay sewage rates.

 

It may not be the answer for you, as it depends on circumstances.

However I think my decisions over the years has been 2 treatment plants to every  pump.

 

[gravelrash]

I used Drainstore 15 years ago for there own sewage treatment plant... I ended up converting it to pumping station 4 years later as it was rubbish. 

Im currently building another house next door which will have a sewage pumping station which pumps to my current pumping station tank and I have been told by YW I do not need S106 to connect.

[saveasteading]

I don't think it was answered above. Excuse me if I have missed it.

Cord-pull for bathroom light.

I got this wrong about 4 years ago, and realised I was out of date.

Light switch can be in a toilet because it is assumed that you will not be using it while standing wet and barefoot in a puddle of water.

Close to a bath or shower is another matter, hence putting switch outside the room.

The pull-cord has its place if you might want to switch on the light and fan in a bathroom, from within, if it goes dark or steamy.

[PeterW]

2 hours ago, WWilts said:

Anyone used Drainstore packaged sewage pumping station? (packaged pumping chamber)

 

Any good or bad experiences? Any recommendations for or against any make of pumping station?

 

If it is your primary pump station then it needs twin pumps and alarms - they need cabling back to somewhere in the house and you also need to lay armoured cables etc so put plenty of ducts in. Also need to know the water table and ground conditions. 
 

Needs designing properly based on number of people and BCO may want to see calcs. I’ve use MPC Services in the past quite happily and they have decent presale and after sale service. 

 

[Dave Jones]

pumped chambers are easy to fit and maintain, had one in previous house. infinitely better to be on mains sewer.

 

£1300 quid mark

 

https://www.tanksforeverything.co.uk/waste-water/pump-chambers-for-sewage-or-effluent-p/sewage-pump-chambers-for-domestic-or-commercial-installations-p/harlequin-1100-litre-sewage-pump-station-1100psv1-single-pump-chamber