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Damp and mould in front of house

Discussion in 'Building' started by questionsaboutahouse, 1 Aug 2021.

  1. questionsaboutahouse

    questionsaboutahouse

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    Hi all,

    I've moved into a property that has significant damp marks at the front of the house (see pictures attached). I knew about this before moving in but am slightly lost as to what the best course of action is.

    There is a large carpeted cement step that is raised from the ground and then additional (marked) cement blocks framing the windows. The large cement step is related to the foundation of the house and I don't intend to move it. The windows (upvc) open out to the front of the house and the front garden has been raised and covers the external wall underneath the windows (possibly with mud). The house is a victorian terrace.

    I've spoken with several damp specialists and builders and they advise either injection and/or tanking the entire room (as well as our bathroom and hallway). However, I feel like this is an extreme solution for what seems to be a localised issue.

    As an alternative, I'm considering putting two airbricks into the wall to improve ventilation, cutting back the plaster and adding insulation underneath the windows with a plasterboard in front. Do you think I will need to cut back and rebuild the marked cement blocks? I also thought of digging the front garden back so the external wall is exposed.

    Finally, there are several walls with exposed original brickwork but these have all been covered with a heavy modern paint. I was thinking of removing this paint and replacing with a limewash/breathable paint to also help increase ventilation. Not sure how much of a difference this would make though.

    Any advice would be massively appreciated.
     

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  3. Evren

    Evren

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    Whatever you do ,dont listen to those "damp specialists" as it will get worse.
    Solution is simple ,find the source and eliminate it.

    Question 1 , What is that plastic pipe going in to the ground ?

    Question 2 , is the outside floor level higher than inside the house ?
    If so dig a 10-15cm wide trench around the outside wall and remove all the mud inside. This will probably resolve your problem .
     
  4. oldbutnotdead

    oldbutnotdead

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    What marked blocks? If the front garden is above internal floor level then dig it out so it is below internal floor level (the main floor, not the step). Chop all the rotted wood and plaster off the bay walls, see if it dries up
     
  5. questionsaboutahouse

    questionsaboutahouse

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    Thanks both, that's really helpful.

    Evren - The green plastic pipe has the internet cables in. They run under the garden and out into the neighbours front garden. The outside floor is much higher than inside the house. I'll dig a trench round this week and see if it changes. Do you recommend treating the trench/covering it with anything?

    Oldbutnotdead - by marked blocks, I meant the stained/marks on the cement block at the base of the windows (shown in the window images and with two zoom ins - img 2132 & 2133). I think they're foundational but I'm not really sure...
     
  6. jeds

    jeds

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    It's highly likely you do have penetrating damp there but that situation is also going to suffer from high levels of condensation. First step is to remove soil material abutting the wall outside. I would take it back at least 300-400mm and enough depth for the trench to be well drained. Back fill with drainable material - something like 30-40mm clean stone.

    I find it hard to believe those internal plinths are original? If it were mine I would chip a small section away and make sure they haven't been added by somebody believing they would prevent dampness. Once you get the wall a bit drier I would insulate with a 52.5mm thermal laminate board. But it would look a lot better without those plinths.

    PS. personally I wouldn't put air bricks into the wall. It shouldn't be necessary. Are there trickle vents on the windows?
     
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  8. Evren

    Evren

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    The outside floor level is the problem , dig a trench which will cut the bridging into your house wall.
    I would put a layer of gravel in the trench afterwards but since it is summer you can leave it empty for a while to aid the drying process .
     
  9. JohnD

    JohnD

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    The ground looks very wet.

    Show us the gutters, downpipes, gullies and and other water-carrying components, please.
     
  10. questionsaboutahouse

    questionsaboutahouse

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    Hi everyone, thanks for all points above.

    I spoke with someone today about excavating a trench away from the wall and building a wall roughly 30cm away to prevent moisture from entering into the floor. They pointed out that I should first check with a structural engineer as underpinning might be required.

    To give a bit more detail on the front, the house is on a relatively steep hill and the basement floor has been dug to below street level. The plinths are on the same level as the lowest part of the wall from the outside and (I think) the damp course on the front of the house. I've marked with an arrow in one of the pictures where I expect the original damp course to be. I dug a little bit away from the plinth and it's solid cement.

    As mentioned above, the floor hase been lowered to below street level (about 30cm) which matches the drop from the carpeted cement block at the front. I now wonder if that cement block is from previous underpinning (but it's basically a wild guess given my expertise on this).

    Re: gutters, there is no down gutter on our wall only the neighbours gutter (see picture). There is a stone gutter that runs underneath the windows (in line with the plinths) but it is very cracked and broken. Most of the basement flats on the road have what look like original air vents below the windows and where our utility cupboards are. Only a small number have cut away from the wall and only where a front door or new windows has been added.

    I hope the above is useful. Given structural concerns raised about digging away from the wall, we're now considering tanking underneath the windows and then insulating on top with thermal laminate boards (as suggested above). Open to all other (and probably better) solutions though. Just want something that is going to solve the problem and not make it worse.
     

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  11. jeds

    jeds

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    Could I suggest this:

     
  12. Mr Chibs

    Mr Chibs

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    If you’re worried about underpinning, perhaps you could cut a smaller trench, 150/200mm wide, similar in depth, and as mentioned, leave it empty until end of summer.

    Don’t fill with small (upto 40mm) stones/gravel, as over time this compacts and just becomes solid again and defeats the object.

    As a rule of thumb, render needs stopping at least two courses from the ground, noticed yours goes ground leve (or below).

    Perhaps the gulley is cracked and leaking?
     
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