Finding the drains

[noseall]

Sewers can be any depth, from a few inches to a number of metres down, and as for services, assume nothing other than a very large bill if you hit one. If hand digging, take care until you locate them all, if machine digging then a 'Cable Avoiding Tool' is a must. (Last time we 'assumed' there were no services we were proved wrong. Luckily that cable was only 415V.....)

Precisely.

This is why it is best to assume that there ARE pipes and services when there appear to be none, then dig accordingly.

Even when you do detect a service there is no exact way to determine the depth so you can only estimate or assume.

 

[Hugh Jaleak]

Even when a service is marked on the surface, excavate carefully to locate. For example, do not dig down to expose a plastic gas service with a fork.......

 

[marsaday]

Been at the house today and my neighbour on the end of the chain has a manhole in her garden. I had a look and it is taking a feed from the back and from the front.

So i measured the distance the pipe coming from the front is from her house and it was 1.7m. I assume it will be similar on my house.

The depth to the pipe was 90cm and the pipe diameter was roughly 16cm (couldn't get fully down to see the tape measure though).

so i am pretty confident i can access this pipe ok.

90cm is not that deep is it ?

Would i be best making an access chamber with the plastic stuff which stacks on top of each other ?

Here is a pic of the drain

View media item 65235

 

[Hugh Jaleak]

90cm about 3 ft, not too bad. (When you get to several metres it's time to panic, and when looking at 6.5m plus then it's time to get a bigger machine.... )

Plastic chambers are way to go for speed, dont know of anyone who doesnt use them now. Need to ascertain diameter of existing pipe, then buy a chamber base and risers to suit. 6" stuff will be builders merchants territory, you wont find it in the sheds. Downside is you may have to buy 3m of 6" plastic pipe to get a couple of pieces to make connections either end to the clay.

Alternatively, cut the existing clay pipe to form a half channel of appropriate length, and use the preformed concrete sections to make the chamber. (These are heavy though, be warned!)

 

[Nige F]

Look for any manholes in your front or rear garden and in your neighbours.


Also ask your neighbours as they might already know, normally the old bloke who has lived there for the past 50 years.

Andy

The old bloke will be a remaining Council Tenant - and won`t need to know `owt

 

[noseall]

An external diameter measurement of 160mm would indicate 4" bore although that channel junction looks like 6".

It is fairly simple to graft in a plastic chamber as long as you have all the tools at your disposal and have excavated enough so that you have room to work.

As Hugh said 6" stuff is more decent builders merchant stuff and is 3 times the cost. There are plastic chamber bottoms available with 6" through bore and 4" inlets. Ideal.

 

[marsaday]

Ok thanks. I have the regulations from yorks water and it says i can connect using:

1) a junction
2) a sadle
3) a new inspection chamber
4) a new manhole

The junction is preffered and this is what it says.

Oblique junctions shall be ‘flexible’. Rigid joints will not be permitted. Flexible couplings must comply with the requirements of the Water Industry Specification 4-41-01 ‘Specification for flexible couplings for gravity sewer and drainage pipes’. Oblique junctions shall be the same material as the existing public sewer and be placed in the direction of flow at a 2/10 o’clock position on the existing public sewer. The connection must be at least 225mm from a collar or spigot.
Connections to the public sewer should generally be made using oblique junctions. A junction is inserted into the line of the public sewer after a section of the existing pipework has been cut out and removed. Jointing is by means of a repair coupling at each side of the junction pipe.

The diameter measurement of 16cm was the internal bore. So does this mean my pipe is 6" ?

 

[Hugh Jaleak]

160mm would be 6". (Drain sizes are 100mm/4", 150mm/6", 225mm/9", 300mm/12" and so on.)

I'd go with the manhole/chamber at the connection. If you use a junction then you'd still need to provide some form of access on the new run. Access points at the bottom of a stack are an option, but there's always the fear of what is going to come out when you undo it..... Saddles are used on the bigger pipes.

Junctions are often used where the connection is made in the road. Quicker, and then a chamber is provided on the property to allow access to the pipe up to the connection. Otherwise could end up with manholes every few yards in the road!

 

[marsaday]

Ok i will do a manhole. I havent done any research on making this yet, but is the following how it is done ?

1) expose sewer pipe to be cut. Dig underneath it to allow for the positioning of the new plastic manhole base with an inlet and outlet in 6" and another inlet for my soil stack in 4".

2) prepare a base of concrete for this manhole base to sit on.

3) connect the unit to the clay pipes with flexible connectors. Add units to build the height up to 90cm approx.

4) connect up the 4" soil pipe from my house.

 

[Hugh Jaleak]

'How to' guide (with pics) in the Paving Expert link. They're doing a 4" pipe but principle is exactly the same. Maybe worthwhile investing in hiring a 6" drain plug, just to seal off upstream whilst you get things in place. Inevitable someone upstream will decide to pull the chain whilst you're working.....

 

[marsaday]

Yes i was wondering how to do this. Ta for tip.

 

[noseall]

Dig a (big) hole and expose about 1.2m of pipe and dig underneath etc.

Fit a piece (250mm) of 6" plastic pipe into both ends of the chamber, chamfering the ends to suit.

Position your new chamber on top of the existing pipe so that you can mark the cut lines onto the clay pipe. You will need to position the chamber so that your cuts avoid or are not close to any existing collars.

You only need enough space so that the chamber and the pipe ends just slot in. Cut out and remove pipe section.

Loosely fit a pair of Fernco rubber clay-plastic connectors onto the plastic ends of pipe on your chamber bottom and lower the whole thing into place.

Lube the ends of the connectors and slide them into place. Level across the chamber (one way only and not up/downstream) then tighten the Fernco connectors.

Mix some semi-dry concrete and pack it under the chamber levelling again to suit. Be careful not to put any concrete near any of the other chamber inlets or interfere with the Fernco screw heads.

Fit the risers, so that when you start digging the new svp line you don't go and fill the chamber with spoil.

Job done!

P.S. we would do it after aboot 10:00 am and not bother with a drain plug. I am well versed and pretty swift though!

 

[marsaday]

Thanks Noseall, sounds pretty straight forward.