Drainage issues

[MalekoUK]

Right, so we have had some right fun with our drains the past few months.
We recently had a new inspection chamber installed as we had no access to our drains as the previous owners had build over the old one and we had started to have issues, so had the drive dug up and a chamber installed.
So, a bit of back story.
Been in our house for several years now and only the past two we have had issues start to arise.
It started a couple of years ago when the front rain drain would fill up with foul waste, I was able to unblock by man clearing the trap and jetting with hose. We always assumed the drains went down the front of our house (we have a ramped drive, so made sense in my head).
This issues happened a couple of times in winter, but nothing major, always corrected it.
Then end of last year foul waste was up again but at both the front and bath drains.
Got someone in and long story short we found the drains ran the way I have drawn out. Via the neighbors access chamber they managed to go up the pipe to our end and clear the blockage - all the neighbors foul goes into their access chamber, so wasn't them blocking us.
After the blockage was cleared and the new chamber installed our side it blocked a couple more times. This was found to be a metal handle stuck in the pipes from our side (thanks kids) and also a build up of sediment which was removed. Pipes now totally clear. All good.
A few weeks have gone by now and I lifted the access on our side to have a look and found what you see in the photo.

This is what I thought was happening, even prior to the chamber being installed.
Waste was making it's way up the front rain drain pipe. In the photo it went up maybe a foot or two. I was easily able to clear with a jet and break it down as I cleared it out.
Now it's all clear again.
So, what the heck? The new build up is due to the toilet waste being so close to the chamber it's just smashing up inside and again makes it way up the front.
I have thought if a back flow valve like this: https://thefloodcompany.co.uk/110mm-non-return-valve/ would benefit this issue? Or would that just get blocked from the foul waste and then not function after the fact?
Sorry for such a long winded post (and hope it made sense!), this has caused us a LOT of bother the past few months, and a fair bit of cost involved.
I am concerned now that even if I just ignore it the build up next time will just makes its way down the drain and get stuck/build up blocked. Granted now there is now obstacle in the pipe to get it caught against.
Side note, the reason we saw this in winter the past two years prior I believe was down to more rain going down the front drain and then causing it to back up itself.

 

[Harry Bloomfield]

Right, so we have had some right fun with our drains the past few months.
We recently had a new inspection chamber installed as we had no access to our drains as the previous owners had build over the old one and we had started to have issues, so had the drive dug up and a chamber installed.

I think, if the original chamber is still there, you need to locate it. If it has a metal cover it should be easy to locate with a metal detector. A camera down your drains would help trace any obstructions like tree roots and damage. If you have shared drains, from the point where the share begins, it is the responsibility of your water company to deal with.

 

[Ian H]

You chamber has decent uprights between the channels so suppressed you get the paper jumping out.

Does your toilet join on the left side of the picture? I wonder if you have a bit of backfall on one of the upstream sections that’s slowing everything down.

 

[MalekoUK]

You chamber has decent uprights between the channels so suppressed you get the paper jumping out.

Does your toilet join on the left side of the picture? I wonder if you have a bit of backfall on one of the upstream sections that’s slowing everything down.

I should have labeled the photo, but here are the inlets.

 

[Nige F]

Yep - it's jumping - better than Eddie the eagle Is there any outlet you could feed into the left hand rain drain - to add more water flow ?

 

[MalekoUK]

Yep - it's jumping - better than Eddie the eagle Is there any outlet you could feed into the left hand rain drain - to add more water flow ?

Unfortunately not. Front of the house, just a down pipe from the guttering. Although I am getting that checked as I don't see water flowing down it much when it rains, so might be blocked at top, still won't be a much water in summer etc.

Would a back flow valve be an idea?

 

[Ian H]

I don’t think the non return valve would help.

I’d be thinking because the SVP is so close to the chamber it would be better to come in on a Y junction upstream of the chamber, that would stop it jumping over the channel.

 

[ETAF]

isnt the front drain section blocked with foam, or am i miss-seeing the image

 

[Nige F]

It's soft toilet tissue

 

[MalekoUK]

I don’t think the non return valve would help.

I’d be thinking because the SVP is so close to the chamber it would be better to come in on a Y junction upstream of the chamber, that would stop it jumping over the channel.

That was my thought and worry, considering we have just had it all dug up and buried lol. Certainly something I could do myself at a later date.

 

[Nige F]

I should have labeled the photo, but here are the inlets.
View attachment 222082

Many years ago we had problems with a well known drainage manufacturer - they decided to make a plastic base that could be bricked up from and form a conventional manhole. Same problem as yours ! They remedied it F O C with a formed plastic panel fixed to the opposite wall and hanging in the channel @ the bottom . - Splat, slide, wash away. Seriously I would get yourself a piece of uPVC fascia and using that strange thing fixed halfway down the chamber; , hang the panel ; It'll either work or fall down - But make sure the fixings can't drop off and go down the drain.

 

[MalekoUK]

Many years ago we had problems with a well known drainage manufacturer - they decided to make a plastic base that could be bricked up from and form a conventional manhole. Same problem as yours ! They remedied it F O C with a formed plastic panel fixed to the opposite wall and hanging in the channel @ the bottom . - Splat, slide, wash away. Seriously I would get yourself a piece of uPVC fascia and using that strange thing fixed halfway down the chamber; , hang the panel ; It'll either work or fall down - But make sure the fixings can't drop off and go down the drain.

Interesting idea.
I have seen chambers that have barriers you can install, but no option on ours.

 

[Ian H]

You could probably slit the unused channels and add some to test it.

 

[MalekoUK]

You could probably slit the unused channels and add some to test it.

I can get some thin plastic sheet, cut to size and glue with solvent cement, block those unused gullies to see how it helps.

 

[Hugh Jaleak]

Who was the Manufacturer of the chamber? Osma make channel covers for unused inlets on their chambers. OsmaDrain-450mm-UIC-Base-ChCover-RH-BK (wavin.com) Possibly the part Nige was referring to.