very blocked 180mm steel surface drain

[tvrosam]

Hi all any assistance on this would be greatly appreciated.

(this is a fairly long and possibly complicated post.. please bear with me)

On the attached sketch of our property you will hopefully see a grey line. this is (i believe) supposed to be a surface drainage pipe coming from the neighbours ditch through our property and on to another ditch.

(I should point out that we are on a slope and they are higher up that us..)

The issue is that the pipe is blocked and their manhole overflows under our fence in the bottom left of the sketch.

I have been trying to investigate where is blockage is.

So far I have dug 2 holes between the bottom left boundary and the point where the pipe goes under the house. The pipe located in these 2 holes was 110mm orange plastic (standard underground drainage pipe).

The neighbour has been able to rod between his manhole and the bend, cant get round this bend as its a 90degree!!

I have rodded up from the ditch to point B on the sketch (approx 20 odd meters). I know that its under the garage because i hired a cat3, sonde (mouse) and cobra (150m yellow fibreglass rod).

I wasn't able to get any farther than point B.

I then estimated the position the pipe would be on the garden side of the garage and dug a trench at point C on the sketch. I located the pipe and performed some surgery to allow access.. no water came out and I found that the pipe was 90-95 percent full of soil, clay, sludge, gravel and bits of coal.. yes coal.

From point C i was able to rod up towards the house (and use the CAT) to get a semi accurate position for the pipe, but was unable to get past point A on the sketch. neither drain rods nor the cobra were able to penetrate this point.

I also rodded in the other direction (under the garage) and again was unable to get past point B. my hook attachment on the drain rods did bring me a nice piece of coal though.

So.. what should I do..
1) How can i shift the blockage just inside the front of the garage?
2) What can i do about rodding the 90degree bend(s) under the house.
(I think there may have been a manhole there at some time in the past?)

3) Leave it to the neighbour to sort out.. as strictly speaking i think, since we don't discharge into the pipe at any point, it is their problem.


(The pipe is 180mm, so i have to source a coupler to repair it.)

Untitled

• tvrosam
• 27 May 2012
• 1

 

[Hugh Jaleak]

A jetter should be able to cut through most of the crud, provided the debris has washed into the pipe and is not the result of a collapse. Jetter however may also struggle to get round those bends.

Ideally the pipe wants relaying around the house to omit the dog leg, why it wasnt relaid at the time the house was built I dont know! Or possibly better still, relay the entire run in a straight line! Is your neighbour willing to contribute to the cost to sort this out? Unlikely to prove cheap whichever way you go about it....

 

[tvrosam]

ive just been looking at jetting equipment.. not cheap to hire but might be the only option.

we did consider relaying the entire thing. it would mean hiring a digger and the cost of the gravel alone would be pretty steep i should think. but it could still be the best option.

removing the dog leg section may well be the next best option IF i can get the lower section cleared.
The extension that that sits under is fairly new (5-8 years) so why they didnt sort it out then is anyones guess.

one thing i thought might be worth while is to add a rodding or access point a the hole i have open outside the garage (point C in my sketch). the issue is the pipe is 180mm so I doubt i can get standard connections etc to construct a rodding point.
is my only option to build a brick manhole with a concrete "valley" in the bottom?

cheers.

 

[HERTS P&D]

Phone around for a quote for having it jetted out.

Get 2-3 quotes and come back on here with the prices.

Andy

 

[Nige F]

So far I have dug 2 holes between the bottom left boundary and the point where the pipe goes under the house. The pipe located in these 2 holes was 110mm orange plastic (standard underground drainage pipe).

]

Where is the steel pipe

 

[subman101]

So far I have dug 2 holes between the bottom left boundary and the point where the pipe goes under the house. The pipe located in these 2 holes was 110mm orange plastic (standard underground drainage pipe).

]

Where is the steel pipe

What steel pipe? I see no reference to one

 

[Nige F]

So far I have dug 2 holes between the bottom left boundary and the point where the pipe goes under the house. The pipe located in these 2 holes was 110mm orange plastic (standard underground drainage pipe).

]

Where is the steel pipe

What steel pipe? I see no reference to one

It`s in the title - " Very blocked steel 180mm surface drain " Is it 6 inch spun cast with caulked joints

 

[tvrosam]

So far I have dug 2 holes between the bottom left boundary and the point where the pipe goes under the house. The pipe located in these 2 holes was 110mm orange plastic (standard underground drainage pipe).

]

Where is the steel pipe

What steel pipe? I see no reference to one

Right yes.. sorry its the grey line going from bottom left to top right in the image.

 

[tvrosam]

So far I have dug 2 holes between the bottom left boundary and the point where the pipe goes under the house. The pipe located in these 2 holes was 110mm orange plastic (standard underground drainage pipe).

]

Where is the steel pipe

What steel pipe? I see no reference to one

It`s in the title - " Very blocked steel 180mm surface drain " Is it 6 inch spun cast with caulked joints

Well.. I haven't got a super accurate diameter. Its about 180mm.
There is a weld along the top, so I'm guessing its not spun.. more like wrapped and welded. Its fairly thin. 2 or 3 mill thick metal.
Havent been able to get at a joint so far, so not sure about that.

 

[Hugh Jaleak]

If you want to construct a manhole cut the top half of the pipe off and remove, this leaves you a ready made channel. Concrete base under and around the pipe level with cut sides. Build off the concrete, either engineering bricks of precast sections. (Will need 9" brickwork if using that option.) Bench sides to suit.

You may be able to clear the lower section from this point and you then have the bonus of allowing you to 'see' whats happening, flowing water through channel means its draining correctly. It also provides access up and downstream in case of future problems.

 

[tvrosam]

Hugh, yes i think having access would be better than just repairing the pipe and covering up.

if possible I'd like to just fit a rodding point.. but adapting 180mm to standard rodding bends/pipes/eyes doesn't seem possible/straight forward.


I have already cut a 200mm(ish) section out of the pipe so will have to either install a pre fab inspection chamber (I believe its called an IC), or as you mention.. build a concrete base then brick up from there.

now.. I'm a DIYer so please forgive the stupid questions.. what do you mean by "Bench sides to suit"?

the other potential issue is the hole/pit where all this is going on is downstream from a soak away (star shape on the sketch)... do I need to keep the concrete channel that il be casting dry while it sets?
(i know concrete going off is a chemical reaction and will work even under water... but im assuming that the water tightness of the gulley/channel will be affected if there is too much water in the hole.
I could pump it out with a dirty water pump.

 

[Hugh Jaleak]

Preformed chamber would be in the industry standard sizes, 150/225 or 300mm so may present an issue with adapting to the 200mm pipe. I'd cut the top half of the pipe away, this then leaves you a ready made channel, much easier than trying to form something out of concrete unless experienced (and even the pro's would probably cut the existing pipe to use as a channel). Also allows the water to flow through whilst concrete is placed. Then build up from the concrete base you've set, if you're doing things manually then bricks probably easier, concrete sections are awkward and heavy!

Benching is the term used for the area of the chamber between the half channel and wall(s) of the chamber. Ideally built up using concrete and finished off with a layer of granolithic mortar. Some good diagrams to be found here: http://www.pavingexpert.com/drain05.htm#defn and info on granolithic mortar: http://www.pavingexpert.com/mortars.htm#grano

If groundwater is a problem then dig a sump about the size of a builders bucket to one side and put pump into that to keep water level down whilst your concrete goes off.

 

[Nige F]

Let`s get back to basics - it`s a rainwater drain - we`re all over engineering it Plenty of farm drains are accessed along the runs by simple pits with flat concrete bottoms and single concrete block walls ( or single skin brick) The pipe - of whatever material/size comes in one side - cut flush with the wall -and goes out the other side . That includes bends , junctions etc. . Dig some holes , cut pipe straight through , pour a bed of concrete ( dry mix if there`s groundwater) run some bricks up on it - put a lid on - simples

 

[Hugh Jaleak]

You have a point Nige... Might even benefit from having a catchpit, collect the coal out the pipe, dry it out and nice fire for colder months.

 

[tvrosam]

so..
I think I'm going for a concrete base and bricked/blocked up sides with a 450x600 mm galvanised lid, possibly with a catch pit which will save having to mould/shape a channel in the base.

i think this will be cheaper than buying plastic IC's, risers and having to use adaptors to go from the now non standard pipe to the 160mm available on the IC.

do i need specific bricks / blocks?
I have read that engineering bricks would be the thing to go for. but will blocks be just as good and quicker to lay?

cheers.