Build over/next sewer and overland flow

I am planing KDR in Sydney, engaged Wisdom Hone, they added $10k each for above items including encase sewer pipe, there is no flood report at local council. I am not sure what to do? I don’t want to sign the tender until I find out these issues. Can anyone give some advice? Before tender acceptance, should I request them to do flood report and hydraulic assessment and also check with Sydney water about the requirement for my build? Is this normal? To find out more details before acceptance my tender? Does Wisdom homes arrange this before tender acceptance? And i will pay for it? Thanks

Your suspicions are warranted
Find someone independent to do a site and cost analysis before you engage with any new home salesman
You'll need a survey, geotech report, Engineering and details, you can enquire with the water Corp engineers
To put things into perspective a salesman's job is to sign you up, get a deposit, allow other to sort things out, for which they get paid a Big Commi$$ion
At worse they are allowed to make mistakes, leave things out and underestimate costs
and many a client has been told that in the Builders office after Preparation of Plans when firming up estimates.

Thanks for your information. I try to find out these steps in right orders. i guess I need to have the design to approach to hydraulic engineer including flood report and sydney water for BAS. If I accept the tender now and pay additional for contract and deposit etc. what if I cannot build it or the building cost will be significantly increased due to the flood report and BAS?

With the BAS concrete encasement is a last resort where you have no space or can't transfer new building load to below a 45 degree rising up from the bottom (invert level) of the pipe.

This link tells you the requirements for BAS:

https://www.sydneywater.com.au/web/groups/publicwebcontent/documents/document/zgrf/mdc2/~edisp/dd_076198.pdf

If you register will DBYD (free takes 2 minutes) you can find depth/location, type etc of sewer and how much space you have.

https://www.1100.com.au/

It might also show if encasement required for neighboring houses if not SW have the info but I'm not sure if you need to open a file or something with them or if they have a general chit chat helpline

Building over or next to assets (sydneywater.com.au)

Usually if a SW asset under a site it will be a condition of the DA that SW consent is obtained prior to CC via 'tap in'. Perhaps its a provisional amount or something-ask the builder why encasement required. Probably will be a few piers to below zone of influence but Id get the geotech report done first if not already.

Hi worldofmud, thanks for these useful link/info, I registered and recevied a lot of emails from different authority including sewer diagram but it did not have information around depth of it. I guess I need a pegout report (what the build told me to do).

I also registered with SW, very easy to use.

The Dial before you dig Water Authority Maps will have all the information on it
Down load the pdf notes that generally accompany the maps it will help with interpreting the data, dos and don'ts,etc
You're looking for the size pipe, invert level, manhole, info ,etc
Your engineer will certify pile details, centres and depth
OT, generally they don't allow for encasement here in WA as there are easements
Cheers
Chris

If it is Sydney Water, you will have to engage a water services coordinator who act as a sort of middleman between the client and Sydney Water. They will organise the pegout. Has Wisdom homes given you a copy of the plans yet as the WSC will need the plans, a survey etc. Once they have that you will need an engineer to give them a drawing for what is needed at the house construction stage showing the piers, footings etc in relation to the sewer.
Here is a couple of my previous posts with drawings
viewtopic.php?f=1&t=69324&hilit=sewer+encasement

viewtopic.php?f=31&t=98872&p=1870511&hilit=sewer+encasement#p1870511

@ Chris. We have had several quotes from arborists , excavators and others both recently and in the past who say they won't accept the DBYG drawings as they can sometimes be way off. Generally I've found them to be roughly right but a mate found one pipe that was at least a metre away from where it should have been.
I'll get one for our place when we are nearer to demo ( for the relevant officials ) but i've already done careful exploratory digging, located all pipes on our nature strip adjacent to our two side boundaries and logged the depths and positions on a sheet.
A much better method in my book.

Stewie

Hi Stevie,

Lots of useful information in that post, thanks.

It is Sydney water, I thought that if we pier down past the zone of influence to avoid possible problems with the sewer pipe and not actually concrete encasing them. But It seems like that Sydney water make you to encase the pipe and pier down pass the zone of influence within 2 m of their asset.

I designed my house smaller than what we want due to this issue, if we need encase it anyway I may want to design a bigger house to build over the pipe.

Current building plan is to build next to it (within 2m), it’s mainly the garage side.

We are having our sewer concrete encased on Friday. As you can see in my drawings there are no piers as it is all on rock and is because we have two retaining walls straddling it. We are also having out point of discharge moved 3m downstream to give us more fall from the basement ensuite that is going to be under our rear terrace. All up it is going to cost us just shy of $10k.Other quotes were similar. Some quoted around $6,000 for just the two concrete encasements.

Stewie

In addition, there is a stormwater easement next to the sewer pipe close to the boundary. Do you know how close I can build next to the store water line? I searched online it says 1m away from the outside edge, is this info correct?

I tried to ask our builder, they tended to ask you to sign the tender and pay deposit then start this process. I don’t want to lock myself into something I don’t know how much it’s going to cost me.

The stormwater line I'd imagine would be owned by your local council so you should ask them. Individual councils have different rules and guidelines.

Stewie

We are having this same issue. We have been given a 30k allowance for sewer encasement and costs associated subject to sewer peg out. Massive blow to the budget so much we had to remove the pool. We ordered reports but can't find depth. Seems opposite corner who have sewer line running up side same as us have not encased theirs . Cab we request a copy of Wosdom sewer peg out to get independent advise before going any further. We offered to pay for sewer peg out before signing contract but they will only accept the one they order to give us final costs and we had to sign contract before they would do that

Hi Lindsey, are you going to build over the sewer or next to it. I am wondering if it makes any difference in term of the cost. We have limited the size of our house, if the cost will be the same, I prefer to build a bigger one. I also spoke to the builder to order the peg out and get more accurate cost for this part before we sign the contract, I have not heard anything back yet. I don't really want to sign some thing that I have no idea what it's going to cost, I have PC sum for 10k for encasement and you have it for $30k. I am confused now.

Hi our sewer line appeared after land registration and our solicitor told us it would be no issue however Wisdon are saying we are building too close to it ( runs across the front and up the side , corner block ) ours is 10m for encasement and 20k for an associated cost for sewer. I will check my contract and let you know. We aren't willing to change the size of our home so just hoping the report comes in and it is not deep and costs are less. We are also chasing builder from opposite corner as to why they have not touched the sewer line which is in same location for the build they are doing.

10k for building adjacent provision and 20k allowance for encasement is ours

Lindsaytam

So you can compare, it costs us around $600/lineal metre to encase a sewer and then you have to allow some money fo design fees and other stuff. So if you are encasing a 10m sewer it would be fair to allow a budget of $1000/metre or $10,000 as a guide

good luck

Simeon

Hi, I just had Peg out done yesterday, still waiting for the report, I was told that the sewer pipe is 2.05m deep from the manhole on my driveway, what does this mean to my build? I am sure I will have more information once the building company gets the report, just want to know more info about it. My current plan is to build next to it (within a meter), if the requirement would be the same for building over it, I may choose a bigger one and build over it.

It means you are going to need piers probably around 1.7 to 1.8m deep to get down past the zone of influence if you are looking at building only 1m away from the sewer.


Stewie

Hi Stewie, what if I build over it, I guess i will be required to encase and also to pier down pass the zone of influence?