Drainage question

[Dylan123]

Hi,

I have a 30s terrace. Built on a slope front to back, back being lower.

at the front (raised side) the path has sunk under the bay window below the level of the drains (either side)

One drain has the surface water from the guttering and seems to work fine.

However, when it rains a large puddle appears in the middle (naturally, as it’s below the level of the drains).

I am going to concrete over the sunken path so water can get away from forming a puddle and go to the drain, however, the other drain (which has no pipe from the guttering and seems to be just for surface water from the garden) on inspection is blocked with all sorts of Earth and debris.

I can clear some of this with my hands and then mop/boiling water, but I’m concerned the drain doesn’t work.

how could I test this? I can get under my living room....is the drain deep under the house or can they been seen under the floor (I haven’t been under yet but I know there’s space to crawl under there by the aspect of the house and the neighbour said you can)

I have a combined water/sewage manhole, I could run some water with food dye in it and check under the man hole to see if it comes through?

before I level the path I need to know if this drain works so any advice appreciated. As it’s not had any flow (as no water has been getting to it) it looks dubious if it will work. Or do I need one of those rod companies?

If I can get water through I’m still worried it’s broken and going to lead to subsidence. Also worried why the path sunk but no cracks or signs of anything moving in the house, just seems like it’s very old and has sunk.

cheers

 

[KenGMac]

Dylan123, good evening.

Suggest you consider making an Insurance claim under the heading of damage to underground services.

From your post, you have demonstrable damage occasioned by a leaking drain.

Ken.

 

[Dylan123]

Dylan123, good evening.

Suggest you consider making an Insurance claim under the heading of damage to underground services.

From your post, you have demonstrable damage occasioned by a leaking drain.

Ken.

Confused as how you got to that? Are you saying the path has sunk and that can only be due to a leaking drain?

the homebuyer report didn’t mention it. not that they’re that in depth.

I was of the impression that paths don’t always sink due to broken drains and it could be due to them lying there for 90 years?

 

[KenGMac]

path has sunk and that can only be due to a leaking drain?

Yes.

What else causes a [so called] "Wash Out" of fine material [earth] ?

Or is there a massive roof rain water gutter leak ?

Ken.

 

[Dylan123]

Yes.

What else causes a [so called] "Wash Out" of fine material [earth] ?

Or is there a massive roof rain water gutter leak ?

Ken.

OK so best to get a CCTV survey of the drain then? That would be conclusive right?

 

[KenGMac]

Dylan123, good evening, again.

As posted, make an Insurance claim, then your Insurer will fund all investigation costs, including a CCTV survey and the possibility of repair if indeed there is a drain leak.

Ken

 

[Dylan123]

Another question here. My wall has no cracks, external or internal it looks fine.

the path just in front of it sinking. This doesn’t necessarily mean subsidence does it?

I’m a bit worried now....report said no sign of subsidence.

 

[Hugh Jaleak]

Paths can sink for various reasons, if the house isn't showing any sign of cracking (and has stood for the best part of 90 years so far without issue), I wouldn't panic unduly.

How far are these drains apart from each other? Unlikely they'd run under the house I'd think, possible both are connected to the sewer, but the blocked gulley probably doesn't get much flow through it so has slowly silted up over the years. Start off by testing the known working gulley, drain testing dye is available from Screwfix etc and will probably be more obvious than food colouring. See if that appears at the manhole, if not then you may have a soakaway.

Assuming rainwater is connected to the drainage, move to blocked gulley and clean that out, use stout rubber gloves, and a tool of some sort, ideally if you can get a wet vac, this would be preferable to blindly shoving your hand into the unknown. Make sure the 'pot' is clear and find the outlet, which will go back up on itself, and ensure that is also clear of any detritus. Test with buckets of water/hosepipe and see if there's any flow, if it goes away then problem solved.

If it doesn't, then options are to get it jetted out, (ring round for a fixed price and avoid the 'Franchises, they're not called 'Dy** Rob' in the trade for nothing), again, if this solves it then all is good. If not options remain, dig it out, try and trace the run and/or reroute to couple to known working drain, or realign the levels of the pathway to fall to known working gulley.

 

[Dylan123]

Paths can sink for various reasons, if the house isn't showing any sign of cracking (and has stood for the best part of 90 years so far without issue), I wouldn't panic unduly.

How far are these drains apart from each other? Unlikely they'd run under the house I'd think, possible both are connected to the sewer, but the blocked gulley probably doesn't get much flow through it so has slowly silted up over the years. Start off by testing the known working gulley, drain testing dye is available from Screwfix etc and will probably be more obvious than food colouring. See if that appears at the manhole, if not then you may have a soakaway.

Assuming rainwater is connected to the drainage, move to blocked gulley and clean that out, use stout rubber gloves, and a tool of some sort, ideally if you can get a wet vac, this would be preferable to blindly shoving your hand into the unknown. Make sure the 'pot' is clear and find the outlet, which will go back up on itself, and ensure that is also clear of any detritus. Test with buckets of water/hosepipe and see if there's any flow, if it goes away then problem solved.

If it doesn't, then options are to get it jetted out, (ring round for a fixed price and avoid the 'Franchises, they're not called 'Dy** Rob' in the trade for nothing), again, if this solves it then all is good. If not options remain, dig it out, try and trace the run and/or reroute to couple to known working drain, or realign the levels of the pathway to fall to known working gulley.

It hasn’t cracked but I think I’ve figured it out. I’ve uploaded some pics so it hopefully makes more sense.

I pic pics of both drains. The one in the corner works for all I know as the guttering goes down to it and never seen that drain are flooded.

however, you should clearly see the blocked one. Water has never really got to it because it’s higher than that concrete under the bay window.

it looks to me that the concrete has started to slope AWAY from the house and it goes downhill (hopefully you can see this)

I think this is because they put a rockery and there’s mud from the garden pushing down on it, so it’s making it tilt backwards and away from the house and drain....do you think that’s plausible?

basically a large puddle forms there as it never gets to the drains which are a good 4-6 inches higher than that concrete run between the drains under the window.

there is a crack where the concrete meets the wall, but apart from needing a bit of TLC the wall seems straight as a die.

So ideally I want to get rid of that soil, resurface pour that path and ensure both drains work and all the water can get directed there.

we have personal lines to the sewer and mine is out the back. I have a combined surface and sewage one under the manhole.

I always assumed surface water from the front would run and join the gulley out the back at some point . Are you saying it might just drain into the soil under the house. I always assumed that would just encourage subsidence!

 

[Hugh Jaleak]

I'd suspect the blocked gulley is just full of debris that's washed in over the years, and no-one has ever bothered to clean it out. Concrete, could have been badly laid in the first place, if there's not a suitable base underneath, it wont last long. Break it all out, use the rubble as a base and redo it. May even be a soakaway under there somewhere for the rainwater, it's clearly working if there is! Very unlikely it goes under the house to drain, I'm 99.9% sure it would drain away from the building somewhere.

Otherwise you may have a storm drain running under there somewhere, they could be a bit miserly with manholes on storm runs back in the day, so dont rule that out either. Very unlikely they'll have run a storm drain under the building to be honest, at that time the preference was for everything to be external. Only exception would have been the short run from a ground floor WC to outside the building footprint.

Quite possible the rear goes into a combined system, then a separate storm drain takes the water from the front and possibly the road gullies as well.