Encase sewer pre KDR and fencing near manhole

SychoAngel · Jan 30, 2014 8:05 am

We are looking to knockdown and rebuild and have a sewer line that runs through the property. The existing house is set back on the block, but when we rebuild, we'll be doing it over the line

Has anyone had any experience with this, do they know the rough cost? The existing line is under an old paperbark so we will need to replace it as the roots have gotten in

Also, we have manhole to access the sewer line which is away from the house, but does anyone know what the requirement is re fencing? Currently there is no fence near it, but we want to put a colorbond fence along the property line near it post rebuild

Stewie D · Jan 30, 2014 8:29 am

To concrete encase a sewer costs about $1100 per lineal metre. A rip off I know and you can't do it yourself - you have to use a water board authorized drainlayer.
They will make you do a peg out first and I think that costs $250 from memory.
That involves a couple of guys from the water board coming to your place and lifting the manholes upstream of your place and downstream and working out exactly where the mains sewer is and at what depth at your side boundaries. They then do a drawing which they keep for their records and give you a copy to work from.
Then you have to get a draftie to draw up the sewer drawings and submit them plus your final DA plans to the water board for their approval. Once you have their stamp of authority you take those plans and lodge them with the council for your DA.
If you like I can post up a couple of drawings that I have done for clients in the past regarding this.
Your fencing should be fine as it is regarded as a light structure and easily removed for a short section if they have to do maintenance on the manhole. Heavier fences like brick piers and walls supported by concrete footings are a whole different scenario and the water board has guidelines that you must adhere to.

Edit : I forgot to ask before who your water authority is ?

Stewie

SychoAngel · Jan 31, 2014 7:32 am

THANK YOU! That information is really really useful. We are with Sydney water. I have found some information on their website re encasing & how close you can build to the manhole, but it was nowhere near as informative as your post. I thought this would cost about $10k, but if the house is 12mtrs , I guess that would make it closer to $15 once all the drawings and submissions are done

If you could post the drawings,

Lehas · Jan 31, 2014 8:30 am

Interesting discussion. So the plan is to encase the sewer line and build the extension/new house over it? Maybe i'm missing something but how can one get access to the line for maintenance? Asking question cause we have potentially similar problem. Thanks

Stewie D · Jan 31, 2014 12:32 pm

Quote:

So the plan is to encase the sewer line and build the extension/new house over it?

Yes using piers down to the invert level of the sewer.

Quote:

Maybe i'm missing something but how can one get access to the line for maintenance?

You don't but the water board can by accessing the manholes upstream and downstream. Also from gully traps adjacent to most houses for inspecting via cameras etc.
Don't forget there is the board sewer - normally 200mm pipe or larger that services the street and/or suburb then there is your sewer - usually 100mm pipe that joins the boards sewer. If it is just your sewer then you won't have to encase it.
If you are unsure go to your water authority ( Sydney Water for us ) and obtain a sewer diagram for your block. It will tell you where your sewer starts and ends and where it joins the water boards.

And here is one drawing
http://i1212.photobucket.com/albums/cc455/stewiesno1/Picture12.png
And another similar...

Then there is the consternation if you have to build within a certain distance of a manhole - oh joy...

You will also probably have to submit a formal letter indemnifying the water board should they cause any damage if they have to access your place for maintenance etc.

Stewie

Lehas · Jan 31, 2014 1:19 pm

Thanks Stewie D. That is really helpful. Cheers

SychoAngel · Feb 04, 2014 1:38 pm

Stewie - thank you for sharing all that information! I really didn't realise how much went into it all. At the end of the day we will have to do it, but I am more aware of the overall process. Thanks for sharing the drawings also, has opened my eyes up to where the $ all goea

qebtel · May 05, 2014 12:37 pm

is this a Sydney peculiarity? Ive never heard of this happening on a house plot in SE Qld?

Stewie D · May 05, 2014 8:18 pm

I know of several instances in Melbourne where builders were made to pier down past the zone of influence to avoid possible problems with the mains sewer but not actually concrete encasing them. I have no knowledge of what other water wholesalers require in other states. It maybe a case of Sydney Water just being over protective of its assets ?

Edit 06/07/14 : I should have added before that this directive in both cases in Melbourne came from the structural engineers associated with building the houses and were concerned with major foundations bearing over disturbed sub-soils and drainage lines not from the Vic water authority themselves. I'm unsure what their official policy is regarding this type of work.
Thanks for pointing this out Scotty ! ( the builder involved )

Stewie

bashworth · May 05, 2014 10:37 pm

As far as I am aware surrounding the pipe only applies to Sydney, it isn't required in Victoria.

In Melbourne the view is, providing a CCTV inspection shows no problem, then the pipe is better left undisturbed.

Stewie D · May 06, 2014 4:25 pm

It is probably slightly overkill with the concrete however as part of the cost Sydney Water do replace any existing earthenware pipes with PVC DWV as a matter of course before encasing it. In newer suburbs this wouldn't be an issue but around where I live earthenware pipes are the norm for mains sewer lines so any replacement has to be a good thing.

Stewie

SychoAngel · Jul 05, 2014 8:09 pm

Yes - our one has already had some blockages due to the roots from an old paper bark getting into the cracks of the clay pipes - so if anything I welcome new pipes being laid

SteveT · Sep 15, 2019 12:54 pm

Hi
I am building a swimming pool unfortunately running through garden are a sewer line and a vent shaft. Seems funny but apparently i can build over sewer line as long as encase, but it is hard to move vent line and complicated.
Can anyone explain why vent line harder?
I was hoping to just move underground pipes around the pool.
Also apparently the sewer pipes are asbestos...never knew there was asbestos piping. Does Sydney Water have to replace cost of pipes? not my fault they asbestos.
Thanks hoping someone can help.
Steve

Stewie D · Sep 19, 2019 3:17 pm

As per your other post Steve. If you are looking at actually wanting to move Sydney Waters main sewer you will be up for big bucks. At every change in direction they will want a manhole installed which means you'd be looking at four additional ones for what you want to do. At roughly $25,000 per manhole, do the math...

Stewie

Jamson · Sep 10, 2020 5:10 pm

Hi Stewie,

In my own case, the sewer line is located within the front setback. Would I be required to encase the lines only for new driveways to go over them?

Thanks

Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅

Stewie D · Sep 10, 2020 6:45 pm

Yes. If any part of your house/retaining walls/paths are within 2m of the sewer, then you would have to pier down past the zone of influence and concrete encase that part too.
You will have to engage a water services coordinator plus a structural engineer as well and they will walk you through the process. I presume you are in Sydney and are talking about Sydney Water?

Stewie

Jamson · Sep 11, 2020 3:43 am

Stewie D

Yes. If any part of your house/retaining walls/paths are within 2m of the sewer, then you would have to pier down past the zone of influence and concrete encase that part too.
You will have to engage a water services coordinator plus a structural engineer as well and they will walk you through the process. I presume you are in Sydney and are talking about Sydney Water?

Stewie

Ah! I reckon the garage on the right side might be affected too. Yes it is Sydney Water, thank you Stewie D

Given your expertise on this, I am wondering if you could also help shed light on this other question I have posted here on the forum.

I want to subdivide an old block in Sydney South West and that would obviously require full service separation. One of the proposed lots could easily make use of the existing junction but the other lot would need to have a new one installed. From DYBD, a cast iron concrete lined sewer pipe (CICL) is passing through the front of the lot, I checked through Sydney Water's information booklet and they didnt seem to provide much info unless for PVC and VC lines.

Can their S1/S2 contractor easily cut a junction into a CICL line? What would be the cost implication compared to PVC or VC? Are their other alternatives looking at the attached photos? Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅

Stewie D · Sep 11, 2020 8:00 am

I'm not 100% certain but I am sure they would be able to as there are a lot of older earthenware and cast iron pipes out there that have been re-lined over the years and they would have to cut in new connections to those. I was under the impression that they used fibreglass and other types of resin to line them not concrete. I have no idea on costs either but I'd imagine it would be more expensive as there are lots of earthenware to PVC and PVC to PVC adapters of all types and sizes. Cut the pipe and install one and away you go. To cut into a concrete lined or otherwise would require a bit more. We are having our point of discharge changed in the coming months as part of our DA but we'll be doing that at the same time as concrete encasing two areas because of retaining walls over the top.

Stewie

Jamson · Sep 11, 2020 12:40 pm

Stewie D

I'm not 100% certain but I am sure they would be able to as there are a lot of older earthenware and cast iron pipes out there that have been re-lined over the years and they would have to cut in new connections to those. I was under the impression that they used fibreglass and other types of resin to line them not concrete. I have no idea on costs either but I'd imagine it would be more expensive as there are lots of earthenware to PVC and PVC to PVC adapters of all types and sizes. Cut the pipe and install one and away you go. To cut into a concrete lined or otherwise would require a bit more. We are having our point of discharge changed in the coming months as part of our DA but we'll be doing that at the same time as concrete encasing two areas because of retaining walls over the top.

Stewie

Thanks so much Stewie! Valuable info.

DA has been with the council for a while now and they have not said anything regarding this yet despite loads of other issues they have asked us to address.

If you have any WSC you’d like to recommend, would appreciate it.

One last question, the estimate for encasing you posted was from 2014, has that by any chance changed?

I’m always confused by the concept of lineal meters, any chance you know what would the Estimated cost translate to for a standard double garage Driveway?

Stewie D · Sep 12, 2020 7:51 am

With our council I knew from past experiences that they would require us to get a stamp on the plans from Sydney Water before lodging the DA. Now they want you to go onto Sydney Waters website and do a water check ( Sydney Water Tap in Assessment ). Any red flags and they will get you to engage a WSC who need a peg-out to ascertain the exact location and depth of the sewer and will then require you to get structural drawings in regard to your driveway similar to my drawings above.
Only then after everything has been approved from Sydney Water and stamped as such from the WSC would you be able to lodge the plans with the council. I'm surprised your council haven't asked for this already as it could mean a delay of several months in approving your DA. Your draftee or architect should have known this!
I'm pretty sure the cost would be now around $1,500 per lineal m but it will depend on a few factors - ease of access to the area in question, depth of your sewer, slope of the land etc.
Just add up your total lineal metres x $1,500 and you should be in the ballpark. If your driveway is 5m wide for instance, add just a little more for clearance say to 5.5m, x $1,500 = $7,500
MGP is who we used https://www.mgp.com.au/services/sydney- ... structure/ and found them to be very good. They do mostly the Northern beaches but with everything being online these days I'm sure it would be just as easy for them to do your job as it would a local area.

Stewie