Drainage issue down one side of house

Discussion in 'Building' started by MoonMan2, 22 Jul 2010.

  1. MoonMan2

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    I know nothing about this house other than it is about 10 years old. It is detached.

    Down one side of the house the water doesn't look like it is draining away. The ground is quite soft and you hear the squelsh of the water as you walk down the side. When it rains puddles form. THe previous owner laid 3 slabs which are joined to the house such that when it rains the water on the slabs drains towards the house and just stays there. Where the 3 slabs meet the house there is a line of green moss about 3 inches high up the bricks. THere is also one of these big anti-weed sheets laid down the whole side of the house - don't think that is helping with the drainage.

    I think the previous onwner was going to slab the whole side, as there is a load of slabs piled up. They got as far as laying down sheet and placing 3 slabs. I am wondering if they have caused this issue.

    In the house there is a dampish foosty smell at the kitchen, this smell can also be smelled to a lesser extent in adjacent rooms. The kitchen is right next to where these 3 slabs have been laid.

    I have had 3 dampness people out to outside and they didn't pay much attention to outside, were more interested in inside the house and below floor. they are dampness people as well.

    The other side of the house has monoblock and no drainage issues.

    Who should I call out to have a look.

    Is it obvious what is going wrong here?

    I am fast becoming concerned, if anyone could provide a link to a company that specialise in this sort of problem i would be very appreciative.
     
  2. r896neo

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    I can say for sure that the slabs holding lying water against the house is not a good thing and should be rectified. Also if the previous owner had made an error this obvious i would check on the off chance he has used DPM rather than a pourous weed suppressant fabric.

    Are the slabs and associated water below your dpc in the house? if they are near to it or above it then there is a very strong case that is the cause of your damp.

    Damp companies make money from selling damp-proofing solutions and the cynics would say it is in their interest to tell you that using their expensive products and labour is the answer to the issue when it could be as simple as lowering the ground level outside, which is cheap and easy and not something you need to pay damp 'Experts' for.

    I would sooner get a builder in to give you his opinion and he can help you locate the dpc and give advice regarding lowering the ground level and or installing drainage of some kind.

    All of that said, there is of course the possibility that the slabs are lower than DPC and the damp is caused by something else but a bridged DPC is near the top of the most common causes.

    A photo would help here.
     
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  3. noseall

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    It sounds to me like you may have a clay substrate and lousy drainage at the side of the house.

    However, it is not uncommon for ANY building to suffer from poor drainage or evaporation, particularly if it involves the North or East sides of the building and more so if the paved area is very narrow and closed in with say a wall of fence.

    My advice would be to dig out about 8" of material and stone the pathway with compacted m.o.t. type 1 then lay slabs with falls to drains either at the front or rear or both.

    It is quite rare to find a true damp expert. :rolleyes: :cool:
     
  4. MoonMan2

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    Thanks noseall,

    you are right the ground is like clay.

    Very little sun gets to side of house due to neighbour having 2 sheds blocking light.

    When you say "lay slabs with falls", do you mean angle them slightly?
     
  5. noseall

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    Kind of, yes.

    You would normally say peak the slabs somewhere near the middle of the run then fall them to each gutter drop at the corners of the house or so that the highest point is furthest from the rain water gully.

    It is usually not enough to just simply slope every slab away from the house as water will gather at the edges of each slab.
     
  6. MoonMan2

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    I have a friend who is a landscaper come out to have a look. This is the work he proposed down the side of the house.

    The width of this area of land at side of house is about 1.5 metres.

    1) Remove slabs and fabric then put in skip
    2) dig up layer of clay soil and put in skip
    3) dig/build drainage trench down far side running along neighbours fence. This drainage consists of digging so deep, dropping drainage gravel then putting on layer of landscaping fabric.
    4) cover the side of the house with drainage gravel(or decorative gravel - cant remember wot he said), leveling gravel off to ensure water runs down and away from house.
    5) put slab path down the middle.

    He is also going to build a "line of trenches" in back garden as he says this is becoming saturated with water. The trenches in the garden will be so deep, dropping drainage chips then putting on layer of landscaping fabric, a layer of top soil on top of that then finally layer of turf.

    Does this plan sound OK, my concerns are:

    a) The trenches, will the water not just sink into them and stay there?
    b) Down the side of the house, with the levelled off gravel and drainage trench, will it not just take the water to the front of the house, should the drainage trench not continue way past the house to ensure all water is taken away?

    I just want to make sure I am armed with some knowledge before questioning him about my concerns.
     
  7. MoonMan2

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    Ok, I know I keep going on about this but I have just had a different landscaper out and he has a different solution.

    He wants to build a rubble drain against the side of the house running to the front of house. The height difference between back of house and front in terms of "earth level" is one brick. He says that is enough of a gradient for him to successfully build the drain.

    My immediate concern was I wanted water taken AWAY from the house not running against it. He said if the side of your house to too dry it could cause me more problems and used the analogy of clay when it hardens it cracks.

    He didn't think pipe drains was necessary.
     
  8. r896neo

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    his 'idea' of your house wall being too dry is completely ridiculous and the fact that he made up a crap analogy to try and prove his point is pretty pathetic at best and fraudulant at worst.

    The idea of a gravel trench is a common way to try and reduce the issue of the earth levell being close to the dpc. Water will take the path of least resistance and so rather than try to hang around and force its way through your wall it will simply run through the stones.

    The gravel trench is the cheaper but 2nd best option with the best method being to remove all the build up of material along the side of the house to get down at least 150mm below your DPC.

    As for the garden have a google of french drains or land drains. What he proposes is a good idea but wrongly finished. A french drain is a trench with a land drain pipe (perforated flexible 4 inch pipe) surrounded by clean stone/ pea gravel. The water seeps into the gravel using the least resistance idea i mentioned earlier and then runs along the pipe.

    They are very effective but need to be drained to somewhere, usually a soak-away.
     
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  9. MoonMan2

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    Finally worked out how to upload photos, here are images of the side of house in question.


    The 'sand hill' was constructed by myself to ensure water moves away from building.

    and up closed to shed which will be getting destroyed by landscaper


    Anymore comments on where drainage should go would still be welcome.[/img]
     
  10. r896neo

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    whilst your idea of the sand is noble it is worse than having nothing there as sand will hold water quite badly and therfore be holding it against the house, just remove it.

    As for where to drain the trench or french drain to you will have to make that judgement yourself as we can't see the whole site or the lie of the land.

    Bear in mind though that the volume of water will be relatively small and it will be quite clean too so running it onto a driveway would not be a problem.

    The pictures of that area are pretty bad, have you dug down to see what is there? First start with removing the landscaping fabric and then dig a bit to make sure there is no concrete or anything under there.
     
  11. MoonMan2

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    Just been on the phone to the landscaper who is going to do my drainage. He said that he is going to drain the side of the house by use of rubble drain along the neighbours fence to the rear drain pipe of the house. He said he will drill into the rear drain pipe which completes the drain, providing escape route for water from side of house.

    Does this sound OK?

    He says he will require landscaping fabric which allows water to pass through but not soil, which one is suitable?

    http://www.diy.com/diy/jsp/bq/nav.j...refview=search&ts=1281016401885&isSearch=true

    or

    http://www.diy.com/diy/jsp/bq/nav.j...refview=search&ts=1281379263919&isSearch=true
     
  12. freddymercurystwin

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    If you mean to drain into the mains then this is illegal. As a 'professional' you think he'd know that! You ought to be draining into a soakway. Only if the local site conditions mean a soakaway is impractical are you allowed to drain into the mains.

    Of course how the powers that be will find out is open to debate but at least you now know the law.
     
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  13. r896neo

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    The weed block alone will be fine no need for geo-tex there.
     
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  14. MoonMan2

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    I called the council in my area, they said if the landscaper has said that using the rainwater drain is the best option then it probably is. They also said no planning permission is required but it is important that the landscaper follows current building regulations. I asked what that meant he said, it is vital that a "silt trap" is built to ensure that no soil etc from the garden goes into the rain water drain.
     
  15. freddymercurystwin

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    Did you speak with Building Control then?
     

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