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JB

removing roots from a drain

What's the best way to clean out a drain which is blocked. I suspect part of it is blocked with roots.

I have used a pressure washer and drain jet to clear out the first 15 m or so which runs along side the house. Then I hit an obstruction and it isn't moving. It's a surface water drain which runs under a concrete and brick patio so I can't dig it up. It goes into a soak away somewhere downhill from that so I can't find the far end and clear it out from the bottom.

I could use chemical agents but I don't want to as it is a ground water soak away and they could come out anywhere.

Any suggestions?
NorthernMonkeyGirl

Can you borrow a camera on a bendy stick and have a good look at the problem iitially?
JB

Not for the moment. My last attempt to unblock it has left it underwater for the moment. But yes I can probably do that once it's drained.
dpack

if it is roots it means the integrity of the pipe is breached so dig and mend is the only proper option as even if you can clear it the problem will return.

sometimes a clog can be removed using drain rods with the corkscrew type fitting on the end or by vigorous jet washing (plant in a van time) but the original break, collapse or separation will remain to leak or repeat the problem.

sometimes dig and reroute the pipe run can be a cheaper and easier option(under buildings/under nice concrete etc etc )

bad luck mate,such things need fixing properly or else they do tend to cause a far worse set of problems to fix than just clearing the pipe or digging and mending.

somewhere in the ds archives are the photos and traumas of jerkymeister's sewage cascade that involved replacing most of his garden to a depth of a couple of feet.
onemanband

Totally what Dpack said.
IIRC I gave similar advice before regarding your drain.
I know it's not what you want to hear, but from my experience, it sounds like the pipe will need replacing and the soakaway is more than likely silted up too.

I have managed to trace soakaway pipes under lawn (and eventually find the soakaway) by pushing steel pins into the ground to 'feel' the pipe. Most of the time tho it is a case of educated-guess-work and digging holes.
Behemoth

Drain clearing companies have devices for clearing roots but it'll need CCTVing and if its buggered relaying. This can be done by 'pipe bursting' or moling without having to dig up the patio. I've no idea about costs.
JB

Oh well I'll just reroute the pipe and hope that as I do I can find where the soakaway runs and reconnect it after the patio.
gregotyn

This may sound a bit far fetched, but it may be worth your while seeing if you can divine water-2 bent welding rods works for me. You will know if you can divine by trying above a known source of water underground and you can follow its path to start with; for example the mains water pipe into the property should register. If you can do it then try to find the outlet of the water and work your way back, you will find no reaction till you hit the blockage. Then start from the first point of water entry and work down to the point where there is no reaction, and in theory.....that's where you start to dig. There are people who divine for a living so it can't be all bad or luck!
dpack

moleing and burst/reline are more recent than my professional involvement .

a mix of science and art to find the blockages and deal with them can be relatively inexpensive especially if you can do your own digging or use a machine to do it.

relaying is a fairly straightforward job but requires precision and following all the correct procedures to work well,last a long time and pass building regs inspection.

the materials are not hideously expensive but it does require decent tubes,enough correct bends and sweeps ,traps,rodding points etc etc.there is quite a lot of gravel and concrete involved.

perhaps the best course of action is to get a camera down to find the problems (a couple of hundred quid iirc) and take it from there getting quotes and prognoses for the various options.

ps if it is roots establishing what is at the other end of them and dealing with it is a good idea.
onemanband

Certainly for moling (don't know about re-lining) they will need to dig a hole at each end to put mole in and to make connections. So there will still be disturbance to your concrete/paving.

I have used moles for water mains, but not for drainage. They don't go round corners, don't go through concrete and they can only go so far. There is often the need for a mini-digger anyway, or other work that the mole-man won't do, so I've rarely found it economical to use one.
Probably cheaper to relay some concrete than get in a mole-man.


If it was me I'd find the pipe/soakaway junction in order to help clear entire pipe length and to check that the soakaway is not silted up.
JB

... relaying is a fairly straightforward job but requires precision and following all the correct procedures to work well,last a long time and pass building regs inspection. ...


How much will building regs affect this given that it is a ground water / rain water soak away? It really is little more than a rain water pipe running into a gravel pit somewhere
dpack

... relaying is a fairly straightforward job but requires precision and following all the correct procedures to work well,last a long time and pass building regs inspection. ...


How much will building regs affect this given that it is a ground water / rain water soak away? It really is little more than a rain water pipe running into a gravel pit somewhere

if you give them a call on monday they should be able to tell you,at a guess they will say just fix it as it isnt foul water heading for a sewer or septic tank.
im a bit out of touch on the current regs for drainage but rain to a soak away was fairly well down the list in my day so long as it was unlikely to affect a building ,ie under the house to a storm drain or similar situation.
Hairyloon

This may sound a bit far fetched, but it may be worth your while seeing if you can divine water...

Ooh, it's been a long while since we had a good row about divining, and suchlike... Twisted Evil
JB

This may sound a bit far fetched, but it may be worth your while seeing if you can divine water...

Ooh, it's been a long while since we had a good row about divining, and suchlike... Twisted Evil

and there was I feeling all virtuous because I had controlled my urge to bite when I saw that post Very Happy
Mistress Rose

Well it is as good a method as any. You can either randomly put in spikes and risk hitting something like the sewer, or you can try divining. I find it works for me, and for a lot of people. At least then the area to be spiked is narrowed down.

I know a lot of people don't believe in divining, but I think there is a good scientific basis for it; used in all the best geophysics equipment.
dpack

the legal case against the chap making "divine"bomb detectors came down on the side of science.

the double blind trials still have a large prize waiting for anyone who can show it works ,so on yer go.
Nick

Well it is as good a method as any. You can either randomly put in spikes and risk hitting something like the sewer, or you can try divining. I find it works for me, and for a lot of people. At least then the area to be spiked is narrowed down.

I know a lot of people don't believe in divining, but I think there is a good scientific basis for it; used in all the best geophysics equipment.

The joy of science is that it doesn't matter if you believe in it, or not. The facts remain the same. Wink
dpack

as "divining" seems to work for some people some times in the "real world" but utterly fails in a well constructed test where the secondary clues (topography, geology,floral and animal variations,prior knowledge of common practice in pipe laying, etc etc ) tend to zero i would hypothesise that any successes above chance (which in some situations would be significant due to less than subtle examples of the clues above ) are due to conscious or subconscious interpretation of the some times gross but sometimes extremely subtle secondary clues.

it is the use of subtle clues that creates the impression that some trackers and "intruder" detectors appear to have "magical powers" when they are actually observing the marks of minute touches their "prey" created as it passed through the environment or interpreting the locations of bird ground predator alarm calls (or silences) or the faint aroma of washing powder and toothpaste drifting through a forest etc etc .
Mistress Rose

You believe it doesn't work if you want. It works for me. JB

After a lot of digging on a hot day (and the loss of 3 kilos in sweat) I have found a joint between a plastic pipe and a clay pipe. That joint was split and letting roots in, that was problem number one. After that it's still blocked so a few more test pits need to be dug to find the pipe which I then cut into (I'll put a ridding point in there later). That's packed solid with silt but I can clear the 8m upstream but only 1.5m downstream.

By the time I finish my garden's going to look like the Somme!
dpack

well done for getting the first one,it might be another plastic/ceramic junction you need to find at the site of the blockage or the "soakaway" might just be a pipe end in the natural.

the garden will recover Wink
JB

Fairly sure the pipe carries on down the garden because that would end it only about 10m from the house and it could run for another 30m but mostly because there's a section where the garden drops a few steps and just after that it feels like I can feel an gravel / rubble line about 20cm under the grass. The rest of the pipe seems to be about 60 - 70 cm down so there's a lot of digging to sort this out! JB

well done for getting the first one,it might be another plastic/ceramic junction you need to find at the site of the blockage or the "soakaway" might just be a pipe end in the natural.

the garden will recover Wink

You're right, a bit more digging and it turns out the next blockage is where the pipe ends in a buried rubble drain. That drain also appears to be blocked. I've no idea how old that is but it's just a collection of brick bits covered with a thin piece of metal, which has long since disintegrated, buried and now largely silted up.

On the plus side, I do now know what's happening.
dpack

what you do next depends on a few things

do you want a pond?

" " " " cistern for garden water etc?

would re making the soakaway be the best option? almost certainly the cheapest/easiest option

would making a new soakaway further down the garden be the best option?
JB

I'll probably dig out the trench and replace the french drain. I'll still put in the new rodding point but I want to make it so that its cover is not water tight. Then if it blocks again it will overflow through the rodding point and not next to the house. That means a warning that it's blocked and no water pooling next to the house.

I'm guessing at the construction of the rubble drain based on what I can see is already there as being basically a trench filled with rubble covered with something to prevent too much soil falling through and then buried but advice is welcome.
onemanband

I'm guessing at the construction of the rubble drain based on what I can see is already there as being basically a trench filled with rubble covered with something to prevent too much soil falling through

basically yeh, just a hole filled with rubble.

Building control round these parts is usually happy with a 1m cube hole filled with rubble (half brick max), capped with a polythene sheet (dpm stuff).

When I did soakaway for my house I used plastic crates wrapped in membrane - but only because I scored a bargain on ebay.
I capped it off with concrete garage sections - but only because they were there.
And I fitted a silt trap immediately behind soakaway rather than fitting individual traps at downpipes.
dpack

the best shape of hole depends on the local soil,slopes ,volume to be soaked etc etc this linky is a bit technical but covers the issues fairly clearly. Mistress Rose

We have built our soakaway with the plastic crates. What do you do if you are on deep clay and it won't soak? JB

In my case I am planning on building a long french drain. So instead of a cube it will be a trench and allow it to flow down the length of the garden. It is on clay so may well not soak away but if it does reach that point it should flood across the bottom of the garden which would have been the natural result without the drainage but now it won't flood near to the house JB

OK - a few buildery questions about french drains.

20mm or 40mm aggregate to fill it?

DPM (impermeable keeps the drain clear) or woven geotex (permeable so helps drainage but will it let silt and mud through from the surrounding soil) to cover it?
dpack

20mm to 70mm is a fairly usual grade of rubble ie nowt too small or big .

clean graded hardcore ,ie no plaster or mortar and screened to remove the wee bits is among the cheapest suitable stuff but depending what is available locally bargains can be had .
try to avoid new aggregate as it has an extra "quarry tax" on it .

a quick call to building control should get your local approved materials list as different areas have local preferences.

iirc geotex was favourite a while back in the london area

even more techy stuff but this linky has a lot of useful design info.

ppppp Wink

iirc across a slope works better than down a slope where it might puddle at the low end but i think that sort of stuff is in the recent linky.
JB

Ta!

In this case down the slope is better. It will then join to the existing french drain further down. By that point hopefully enough has soaked away to not puddle. If it does then I just repeat the exercise of remaking the french drain down from that and if I have to go far enough then it will eventually reach the ditch at the field edge and join the natural drainage channels.
gregotyn

Give me a clue what area you are in as I have a friend who wants to loose some rubble/stone and so you could probably be selective, by taking some and if you have a long enough trench all of the hardcore. He is sited in the Llanfyllin area by Welshpool, Powys. I haven't told him yet! JB

Give me a clue what area you are in as I have a friend who wants to loose some rubble/stone and so you could probably be selective, by taking some and if you have a long enough trench all of the hardcore. He is sited in the Llanfyllin area by Welshpool, Powys. I haven't told him yet!

Thanks for the offer but Wales is too far away as I'm in Sussex. Though it seems appropriate to be offered rubble from Llandfyllin (yes I know the 'd' shouldn't be there but the pun works better with it)
dpack

Laughing
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