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Solution for drive built too high?

Discussion in 'Building' started by M4son, 4 Aug 2021.

  1. M4son

    M4son

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    I've recently bought a house (FTB) and discovered the block paving driveway has been built up to the house and above the DPC. This appears to be the cause of two areas of penetrating damp to the front and side of the house.
    The land slightly slopes from back to front so the front of the house is minimally affected. The problem there appears to be the driveway has been built up to an air brick and thays where the damp is coming from.
    However to the side, the slope runs the full length of the house so in heavy rain the water runs against the length of the house above the DPC. An additional problem is caused by old sand and cement render to floor level but I've knocked most of that off and the brick work is starting to dry out in the good weather.

    My plan is to remove the course of block paving adjoining the house, dig down to below the DPC and lay aco drains running to the storm water drains at the front and rear corners of the property. It would result in there being a drop between the driveway and the house but I'm thinking I can install kerbs or fabricate a second grate to sit on top of the aco drain, level with the drive - assuming splashback from a grate is less severe than from black paving?
    A couple of questions:
    1. What would be the better and more robust finish? Kerbed edging and then a drop to the aco drain below DPC or a second grate level with driveway and above the DPC that sits on top of Aco.
    2. Would aco drains be reccomended at the front of the property, given the slope is away from the house or would it be sufficient to dig below the DPC and air brick then line with shingle to soak into the soil?
    3. If I installed the aco drains level with the existing driveway and against the house above the DPC would the depth of the drains ensure the integrity of the DPC is maintained, with the only residual risk being splash back from the grate which could be mitigated with sealant paint?
     

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  3. stuart799

    stuart799

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    We have this same issue. Had a rear extension done in the winter and they realised the block paving was all above the dpc. We live in a semi so had block paving in the drive, side path and patio at the back. We're slowly getting rid of it and digging down around 6 inches and laying slabs. We are putting an acco drain at the new patio bifold doors but at the side what we've decided to do is put slabs as stepping stones and fill in with crushed gravel around it to improve the drainage. Damp has improved in the house but still one patch in the middle wall which I can't figure out. In our neighbourhood, rumour has it that some travellers came around years ago and did a bunch of the drives by going door to door and they didn't do them properly; above dpc, driveways settling where the tyres are, weeds coming through all the blocks. Good luck with yours, but I would think pea shingle would suffice but make sure you dig down a bit right by the house so it drains well below dpc. We are putting acco drains only on the sealed patio by the bifolds as more of an 'insurance' policy.
     
  4. johnny2007

    johnny2007

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    Short of lifting it all up and redo, remove a foot of paving all along the wall, dig at least 8 inches below dpc and fill with 2 inches of decorative stones or shingles.
    Hopefully the ground is permeable there and water will drain, if not, lift it all up and redo at correct level.
     
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  5. JohnD

    JohnD

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    rather than shingle, cobbles or pebbles will drain better. The larger the stones, the bigger the gaps between them.

    As well as draining better, water cannot rise by capillary action up large stones, and they do not hold damp.

    You need a barrier, such as landscape or weed fabric, to prevent soil or mud washing into the trench and filling the gaps between the stones.

    You only need attractive pebbles on the top, you can fill the rest of the trench with ugly lumps including clean broken brick and concrete pieces.
     
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  6. JohnD

    JohnD

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    might be a plumbing or drain leak near that point
     
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  7. stuart799

    stuart799

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    Thanks JohnD. I don't want to hijack this thread. I can't see anything but it's a possibility
     
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