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  • Should I be concerned…? Water ingress in garden. New build content.
  • nickhit3
    Free Member

    [video]https://youtu.be/CF05LZ5S-cA[/video]

    Following a mahoosive thunderstorm in the last hour, I was alerted when coming home to the sound of running water in our garden… Opened the back up and saw the above scene shown in the video. The grey pipe emerging from the retaining wall has previously never shown any noticeable water during normal persistent rain but now this.. I’m not a builder so don’t know if the proximtiy of this drainage pipe is good/bad/unusual. There is now a significant ammount of water next to the house and its proximity is slightly alarming. Does it look like a normal location for this type of drain… ?

    The area, as can be seen next to our bin collection, is small and is just a narrow 1m covering of stone chippings along the side of the house, but is within our boundary and responsibility. And more obviously, the water is now pooling in our garden and toward the house… 😕 Clearly the water will soon soak away and disperse, but it seems odd to have this draining INTO our garden area- an area we want to modify in the future.

    Any thoughts or advice? I have good relationship with the developer/ site and the house is just coming up to its 1 year Birthday btw.

    allthepies
    Free Member

    I’d be concerned about that, if you get a few days of heavy rain then things could get much worse.

    nickhit3
    Free Member

    🙁

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    STATO
    Free Member

    What is the retaining wall retaining? If it has a drain you want it to work or it could be a lot of extra weight behind the wall trying to push it over into your garden, but obviously there should be sufficient drainage in your garden to deal with it. Its likely though your grass is just laid on clay so no soak away, do you not have any surface water drains in the garden?

    nickhit3
    Free Member

    What is the retaining wall retaining? If it has a drain you want it to work or it could be a lot of extra weight behind the wall trying to push it over into your garden, but obviously there should be sufficient drainage in your garden to deal with it. Its likely though your grass is just laid on clay so no soak away, do you not have any surface water drains in the garden?

    Thank you for the reply. The wall is retaining a small sloping tarmac access road to an electric substation that is just behind the garden. That road way-which does not feature drainage- and substation are approximately 8ft above the garden, so overlooking the garden in effect. There aren’t any surface drains in the garden, or within any portion of our drive, outside our garage or at the front of the building. The nearest drain for surface water is actually a street one towards the front of the property.

    The water is subsiding and soaking away currently as the weather had broken- and thank you for clarifying the drains function (taking weight from behind the structure) but the fact it exits into our garden just a couple of ft from the foundations has me and my wife edgy..

    one_happy_hippy
    Free Member

    I think I would be asking to look at the levels and drainage strategies for both your property, the road to the substation and the development as a whole if there isn’t any / sufficient surface water drainage to storm water drains or SUDs such that it’s coming out of a drain in a retaining structure at that rate and volume.

    All schemes should be designed to cope with 1 in 30 year and 1 in 100 year storm events so I would be going back to the developers and asking some questions of it and of whoever at the council approved the designs.

    I’m only a geologist but I would consult a civil engineer, I’m sure there are a few on here.

    stumpyjon
    Full Member

    I wouldn’t worry about it, seems to be doing exactly what its supposed to do. Our drive has a five foot retaining wall on one side and has 2 inch holes drilled through the bottom. Normally get little or no water from them even after prolonged rain. However after very heavy rain ive seen it coming out under enough pressure to create a jet of water. Usually after a heavy summer storm when large amounts of fall qu8ckly and the soil behind is dry and doesn’t absorb well.

    nickhit3
    Free Member

    I think I would be asking to look at the levels and drainage strategies for both your property, the road to the substation and the development as a whole if there isn’t any / sufficient surface water drainage to storm water drains or SUDs such that it’s coming out of a drain in a retaining structure at that rate and volume.

    All schemes should be designed to cope with 1 in 30 year and 1 in 100 year storm events so I would be going back to the developers and asking some questions of it and of whoever at the council approved the designs.

    I’m only a geologist but I would consult a civil engineer, I’m sure there are a few on here.

    Thank you. I already have in mind to contact the developer tomorrow. So I may update with any relevant progress.

    I must say that the rainfall I saw tonight- as did many parts of the country see- was heavier than I recall seeing in many years, even in the NW of England. it’s peak lasted atleast 30-40 minutes of torrential rain. Not unusual per say, but heavier and longer than I thought it would be.

    As an aside, I am aware of other neibours in a close proximity (same street-same elevation-but opposite side) having to have surface drains installed due to bad drainage in their back gardens. Sounds like it might be our turn… 😐

    somouk
    Free Member

    I think they are most likely relying on the soft areas of your garden to provide enough drainage for the run off water.

    I personally wouldn’t rely on that and would probably have some more suitable drainage put in, although it was heavy rain yesterday what if it was a consistent downpour in Winter over several days?

    nickhit3
    Free Member

    I wouldn’t worry about it, seems to be doing exactly what its supposed to do.

    Thank you that is some reassurance. In our situation it’s the effect of the water pooling (temporarily) in an area that must be only 1m from the wall of the house that is of concern. And the lack of any drains in the garden or around the house itself.

    I agree the amount I’ve seen is really only sporadic after a thunderstorm and/or only over several prolonged days of rain but I wonder if it might be an underlying issue that needs looked at? My gut feeling is that this is normal given the brief down pour, but I admit to doubting myself the longer I stood there getting wet feet… hmmm.

    martinhutch
    Full Member

    Yep, you need a proper big soakaway or new drain stuck in. I’d be interested to see whether that is water soaking into the ground behind the retaining wall then seeping when saturated, or just draining directly to your yard when it starts pooling above. Looks a bit ‘gushy’ to be the first of those unless it was days of rain. And I would be a bit pissed off if a neighbouring property’s drainage was arranged to just dump the problem on you at the first opportunity.

    hamishthecat
    Full Member

    I’m with stumpyjon. It’s a drain for the retaining structure; I doubt it forms part of the surface water strategy. Worth keeping an eye on but I wouldn’t worry.

    nickhit3
    Free Member

    Yep, you need a proper big soakaway or new drain stuck in. I’d be interested to see whether that is water soaking into the ground behind the retaining wall then seeping when saturated, or just draining directly to your yard when it starts pooling above. Looks a bit ‘gushy’ to be the first of those unless it was days of rain. And I would be a bit pissed off if a neighbouring property’s drainage was arranged to just dump the problem on you at the first opportunity.

    As far as I could see, there was no pooling of water in the areas above the garden- the sloped access tarmac road/lane is bordered by loose chippings but there wasn’t any standing water. I can only summise this is water soaking from the above area.

    Again, this was a VERY large thunder storm period lasting over 30minutes- so in effect several days rain within minutes. Several surrounding main roads were badly affected with several inches of flash flooding etc.

    Also, to clarify: the neibours drain issues do not affect our property and took place prior to the construction and completion of our plot. It is anecdotal information to illustrate potential issues with correct drain procedures on the site that may or may not be affecting me. Just seems odd to me as you say that I’m lacking a drain for that retaining wall drain. I don’t know much about these things but want to know what is reasonable… (I know STW possibly not the best start ) 😉

    jag61
    Full Member

    it does look excessive for a ret wall drain. ive fitted loads in walls over the years never even seen a wet one. I dont think i would want a soak away so close to the house, can you fit a length of 40 mm? drain to under the fence /gate as a temp measure? while developer wrings hands and looks away hope all works out ok.

    one_happy_hippy
    Free Member

    NHBC / BRE design says you shouldn’t have soakaways within 5m of foundations.

    Personally if that was my property I would. E asking lots of questions loudly.

    Drains in retaining structures are generally intended to act to reduce pore water pressure through seepeage over time not as a true drainage feature. The rate that is producing water suggests inadequate drainage at whatever is at the top of the retaining structure to cope with a storm event.

    nickhit3
    Free Member

    Drains in retaining structures are generally intended to act to reduce pore water pressure through seepeage over time not as a true drainage feature. The rate that is producing water suggests inadequate drainage at whatever is at the top of the retaining structure to cope with a storm event.

    This is precisely what I was worried about 😥

    Curiously, we just received a reminder to fill in the new build NHBC questionnaire. Perhaps I’ll hold off…

    hamishthecat
    Full Member

    Stuff happens in exceptional rainfall events. Look at Coverack.

    nickhit3
    Free Member

    Stuff happens in exceptional rainfall events. Look at Coverack.

    Yes I accept this. I also accept this is not comparable to the destruction of a small Cornish village, hurricane Katrina or the Japanese tsunami. It is however, nonetheless a problem, I am looking for answers to from those familiar with buildings and drains- of which there seems a good few offering information. “Stuff happens” is precisely the wrong answer to my issue- indeed one I may face from the developer, but I need to know what to consider telling them.

    one_happy_hippy
    Free Member

    1) Find out rainfall measurement for yesterday.
    2) compare to storm event charts for location.
    3) determine if rainfall is equal to a 1in10, 1in30, 1in100 year storm event.
    4) ask developer why drainage strategy has not been designed to cope with said storm event.

    hamishthecat
    Full Member

    I’m not trying to diminish the issue but as per my earlier comment suggest you keep an eye on it. Severe rainfall events can be outside the design parameters of a scheme and hence may well not be indicative of a real problem.

    one_happy_hippy
    Free Member

    Where in the UK are you OP if you don’t mind me asking.

    Most council will have min. Requirements for new developments in regards to the severity of storms that the development drainage should be able to cope with.

    In fact you can probably look at the planing portal for the planning application and see what the agreed conditions on the drainage strategy were.

    nickhit3
    Free Member

    I’m not trying to diminish the issue but as per my earlier comment suggest you keep an eye on it. Severe rainfall events can be outside the design parameters of a scheme and hence may well not be indicative of a real problem.

    Noted, thank you. You may well be correct, it’s this root cause and effect I’m trying to understand.

    Where in the UK are you OP if you don’t mind me asking.

    I’m in Lancaster.

    one_happy_hippy
    Free Member

    The Lancaster Council Guidance on drainage is easy enough to find for example guidance on SUDs design:

    https://www.lancaster.gov.uk/assets/attach/1228/20150514-FRM-Planning-Advisory-Note-.pdf

    nickhit3
    Free Member

    Thanks for that. Hopefully I won’t need to get involved with that it too great a depth… thought it makes interesting reading and good information to have regardless. I can see other PDF articles from council meeting regarding the development online, some of which allude to drainage but they won’t open.

    Devils advocate here- as I’ve NOT yet experienced any significant long periods of standing water in the area in the video from today (only been in property 11months), and the downpour area has now drained completely- could it be that drainage IS in fact sufficient? Am I making too much out of this?

    wrightyson
    Free Member

    Firstly are there any man holes in the vicinity of your rain water pipes? Even if it all drains in to a soakaway system they shouldn’t just drain into it without access. Also how big is the development? Tin pot local dodgy builder or big boy? Without a shadow of a doubt some attenuation of top water would be required unless the whole site is a like a porous sieve which it doesn’t seem to be looking at your lawn. As above soakaway testing and results and minimum placement are all requirements but under mtb but also building control which is done separately.

    nickhit3
    Free Member

    Firstly are there any man holes in the vicinity of your rain water pipes? Even if it all drains in to a soakaway system they shouldn’t just drain into it without access. Also how big is the development? Tin pot local dodgy builder or big boy? Without a shadow of a doubt some attenuation of top water would be required unless the whole site is a like a porous sieve which it doesn’t seem to be looking at your lawn. As above soakaway testing and results and minimum placement are all requirements but under mtb but also building control which is done separately.

    the nearest man hole i can determine related to our property is located on the other side of the house to this water issue, in the centre of our drive. I assume this is sewerage access for the property. There may well be a central one in the road in front of the house but i have not noticed.

    the developer is one of the largest UK ones. The volume of water shown in the video took approximately 25-30 minutes to soak away- and despite rain over night, nothing is flowing from the pipe shown. As mentioned above, the sloping access road/lane above the side of the garden immediately above the retaining wall drain, is not serviced by any drainage that I can see. The tarmac is flanked by a narrow strip of stone chippings which stop at the garden wall shown into my property. The road runs parallel with the wall at the back of the bin.

    I’m starting to wonder if this is merely a reaction to the exceptional down pour alone…

    However, i am contacting the developer today.

    wrightyson
    Free Member

    So basically the cheeky **** haven’t allowed for any surface drainage up by the sub and that gravel margin at the back of the wall is acting as a soakaway which then discharges on to your property. That in itself is cost cutting slackness at it’s finest and a bit naughty to be fair! Does the rain water from the roof of the sub discharge straight to ground also? At least you’ve got video evidence of it happening which will help your case. There must be more than one mhole as I’d very much doubt on a new development they’d be allowed to install a combined system.

    nickhit3
    Free Member

    So basically the cheeky **** haven’t allowed for any surface drainage up by the sub and that gravel margin at the back of the wall is acting as a soakaway which then discharges on to your property. That in itself is cost cutting slackness at it’s finest and a bit naughty to be fair! Does the rain water from the roof of the sub discharge straight to ground also? At least you’ve got video evidence of it happening which will help your case. There must be more than one mhole as I’d very much doubt on a new development they’d be allowed to install a combined system.

    Yes that appears to be the sum of it…

    I cannot see if there is any drainage surrounding the enclosure of the substation (its behind its own walled structure) that would take the water from the roof, but I may have a peek over the wall.

    It wouldn’t surprise me in the slightest if this ‘cost cutting’ was the issue. Time will tell what their response will be..! It certainly seems wrong to me as a layman to have this retaining drain that collects water from a private lane discharging into my property boundry.. and very close to the side of the house.

    one_happy_hippy
    Free Member

    Having just shown the video to one of the Civil Engineers in the office his response (laughing) was “yeah, that’s not right, id be would be having words with the developer. Good job the house isn’t direct access or it would be under water”

    rider15
    Free Member

    Where is the location of the downpipe for the gutters ?

    Also, under the lawn, do you know how deep it is ? Some building company have been known to level the area using the likes of clay which does not drain well.

    After digging out my front garden, 1ft down and it was a concrete basin…

    Also, are there any more run off pipes on the full length of the wall ?

    nickhit3
    Free Member

    Having just shown the video to one of the Civil Engineers in the office his response (laughing) was “yeah, that’s not right, id be would be having words with the developer. Good job the house isn’t direct access or it would be under water”

    crikey.. appreciate the feedback. 😥

    Where is the location of the downpipe for the gutters ?

    Also, under the lawn, do you know how deep it is ? Some building company have been known to level the area using the likes of clay which does not drain well.

    After digging out my front garden, 1ft down and it was a concrete basin…

    Also, are there any more run off pipes on the full length of the wall ?

    The rear of the property is due south facing, so the problem wall and water flow is impacting the SE corner. The nearest down pipe at the rear of the house is just tucked round the SW side corner. So about as far away from the problem as is possible at the back of the house as I see it. Again, no other surface drains anywhere around the perimeter of the house.

    There’s no other pore/runoff wall drains like the one shown in the retaining wall video, despite the garden being surrounded on two sides by 7ft walls- the edge of the first run of wall being seen to the left in the video at the start.

    Greybeard
    Free Member

    The key point to me is not whether your garden should drain this water, or whether it should be being drained from behind the way (yes) but why is another property draining onto yours. The water should be drained safely without affecting you.

    Greybeard
    Free Member

    Duplicate post

    nickhit3
    Free Member

    Exactly, this has already been mentioned further up and was clear the minute I stood there getting wet. The water is coming from a small access road behind the retaining wall not an adjoining property btw.

    wrightyson
    Free Member

    Keep us posted on this one, be interesting to see if the developer actually GAF!

    nickhit3
    Free Member

    Keep us posted on this one, be interesting to see if the developer actually GAF!

    will do.. 24 hrs and counting with no response to email and video..

    nedrapier
    Full Member

    Good luck, my dad’s 2.5 years into a dispute with the developers over the heating installation in his new build. Fixing it is probably a 10K job. Arguments and evidence are incredibly one sided, they’re demonstrably very wrong, and need to put things right, but to say they’re dragging their feet over it would be understatement in the extreme.

    Presumably they’re hoping he gives up, gets ill, dies, sells the house. No chance of the first, he’s pretty healthy, and staying put for the foreseeable. Court next.

    Hopefully you’ll have an easier job. Yours is a bit more dramatic and it’s threatening the house.

    nickhit3
    Free Member

    Yours is a bit more dramatic and it’s threatening the house.

    still, atleast it’s Friday.

    tjagain
    Full Member

    Ned – 2.5 years? My building dispute ( very complicated involving stat notices and all sorts of shenanigans) is now approaching its 14th year

    matt_outandabout
    Full Member

    Well if we’re outdoing each other on developer stories…
    My brother in law and family nice out today, so that the developer can remove all but outer brick and roof of thier house to rebuild… That’s all internal walls, floor, bathrooms, kitchen etc. The house is less than two years old, cost £650k…

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