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  • #1791979
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    jeff58
    Participant
    Joined: 01 Mar 2011
    Location: SW Haute Vienne, 87 (close to 24 and 16)
    Total posts: 1027

    I’ve read Chris’ article on here, and we have duly removed the cement rendering to well above where the damp had risen.

    It’s situated in a short corridor under the stairs leading to a dining room.

    Sadly, removal of the render shows the problem: the base of the wall is mud. And very damp indeed. The actual ground level outside the house is about 300-400 mm above the floor level in the house.

    I’m really not sure how to proceed now. The ends of all the floorboards have started to rot, and I daren’t think what state the beam is in that is carrying them….

    Anyone? :scratch:

    And can someone advise as to how to post an image or two?

    Thanks.

     


    #1791985
    mysty2
    mysty2
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    Joined: 29 Jul 2012
    Location: N/A
    Total posts: 9603

    There is no product you can put on the wall that will fix the problem.

    If its been like that for years the beams will be rotten but normally just at the ends.

    You either dig out the land adjoining the house and put in drainage, which may help but could well not fix the problem.

    Dig out  the earth drainage, demolish the wall re build with a damp course and replace all rotten wood.

    What I normally do is build a grey brick wall 30 40cm in from the original wall and use that to support the beams, that is a cheap fix, you would need to cut off all woodwork touching the damp wall.


    #1791999
    chris-le-bricoleur
    chris-le-bricoleur
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    Joined: 03 Dec 2010
    Location: NL and 52
    Total posts: 1381

    Jeff,
    Mysty was faster. I would have given the same answer: outside draining, like this:

    Mysty’s proposal re. the internal support wall is a really good one.


    Christian - bricoleur par passion, pas par necessité http://www.klussen-in-frankrijk.eu/

    #1792000
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    mikej
    Participant
    Joined: 21 Jun 2011
    Location: Dordogne sometimes and Kent the rest
    Total posts: 5287

    The most important question is the wall structural, does it support anything above, or is it just a partition between two rooms?

    Lowering the water table as per the two posts above is one solution, but very labour intensive, once the structural questions have been answered we can move forward with a possible simpler solution.

    Mike


    WFIPFLL

    #1792018
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    jeff58
    Participant
    Joined: 01 Mar 2011
    Location: SW Haute Vienne, 87 (close to 24 and 16)
    Total posts: 1027

    It’s the rear outside wall of the house, about a metre thick at the base, supporting two floors and a grenier.

    The land slopes up towards the rear, it looks like they built the house, then excavated to level the inside. You go down two steps at the front to reach ground level.

    We ave the same problem with the two interior dividing walls, since it was more than one property at one time, but both cellars are OK, slightly damp on the floors, but not running with water. They don’t extend right up to the rear, nor to the front of the property, other than an air vent in both at the front.

    At the front interior of the property, the floorboards give way to a smooth cement floor in both rooms, which is always damp along it’s edges. That’s another project, to have that up, fit a damp prof course and probably extend the wood floor.

     


    #1792030
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    mikej
    Participant
    Joined: 21 Jun 2011
    Location: Dordogne sometimes and Kent the rest
    Total posts: 5287

    I am assuming the cellars are not below this wall, you could use the very well proven underpinning technique of hit and miss excavation below the wall and replace each section with concrete to form a foundation and then build up with a dense engineering brick (waterproof) to support the wall, If you can’t get engineering bricks then a DPC would have to be introduced, but I can see difficulty with this considering the height it would have to be at, it could be stepped through the coursing of the brickwork, so not impossible, but would need to be very wide or layered, I have specified hot glue in the past to hold a DPC in position whist laying the bricks, if you could lap this onto a DPC below your floor this would be the ideal solution.

    Without introducing water dumbells  it will be difficult to waterproof the joints between the hit and miss concrete foundation, but these would need to be dowel bared to each other, not difficult to do and a permanent solution without any maintenance.

    Mike


    WFIPFLL

    #1792036
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    mikej
    Participant
    Joined: 21 Jun 2011
    Location: Dordogne sometimes and Kent the rest
    Total posts: 5287

    That should have read DPM below your floor.

    Mike


    WFIPFLL

    #1792037
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    mikej
    Participant
    Joined: 21 Jun 2011
    Location: Dordogne sometimes and Kent the rest
    Total posts: 5287

    To post pic’s on here you need a hosting site, this is much better than any other I have used:

    https://postimg.org/image/hpmg1myjz/

    once you have loaded your image, copy the ‘Hotlink for forums’ and paste into you post on FE.

    Mike

    Jeff you have a PM


    WFIPFLL

    • This reply was modified 22 Aug 2017 12:53 by  mikej.
    • This reply was modified 22 Aug 2017 12:55 by  mikej.
    • This reply was modified 22 Aug 2017 12:56 by  mikej.
    #1792062
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    jeff58
    Participant
    Joined: 01 Mar 2011
    Location: SW Haute Vienne, 87 (close to 24 and 16)
    Total posts: 1027

    [/url]

     

    [/url]

     

    Outside floor level would be about where the level of the top step is in the second photo.


    #1792091
    chris-le-bricoleur
    chris-le-bricoleur
    Participant
    Joined: 03 Dec 2010
    Location: NL and 52
    Total posts: 1381

    Jeff,

    after seeing the pictures I ‘m astonished: your walls are really based on mud?
    If your house is still standing: congratulations!
    It really looks as if the wall was built on solid ground, and then the floor excavated, as you said in an earlier post.

    In this case digging a ditch for outside drainage could de-stabilize the mud under the wall.
    I really do not know a solution for your problem.


    Christian - bricoleur par passion, pas par necessité http://www.klussen-in-frankrijk.eu/

    #1792105
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    Chanceux
    Participant
    Joined: 17 Mar 2010
    Location: Picardie
    Total posts: 13130

    Keep a close eye on the washing machine hoses and dont use it while you are out if it is within the sunken area.

    The cement render was all that was stopping the mud from falling away, are the outside walls the same?


    #1792120
    DominicBest
    DominicBest
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    Joined: 14 Aug 2015
    Location: Poitou Charentes
    Total posts: 2500

    There are plenty of cob cottages made from mud in the south west of England. They are often hundreds of years old and arecas tough as old boots.


    #1792122
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    teapot
    Participant
    Joined: 10 Jul 2008
    Location: Tours
    Total posts: 2372

    There are plenty of cob cottages made from mud in the south west of England. They are often hundreds of years old and arecas tough as old boots.

    <hr />

    Yes Dominic, but they are all cob, not tons of stones balanced on cob or in this case just earth maybe :negative:


    Raising the standards of swimming pool knowledge and technology.

    #1792125
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    Chanceux
    Participant
    Joined: 17 Mar 2010
    Location: Picardie
    Total posts: 13130

    Looks like my cellar after some simpleton decided to add some headroom by digging down.

    Not as high as that and what is exposed is chalk which is not crumbling away but if ever the cellar flooded it would become a milky mush and the whole rear half of the building would drop.

    I havn’t helped matters by creating an external access to the cave through the rear wall.

    Sitting a stone building on compacted soil or in my case a brick building on chalk without foundations was not a problem 90 years ago when mine was built assuming the first few courses are underground but once you expose that soil it will want to fall away and the weight it is carrying will exarcebate that.

    I also had brick dividing walls on the first floor that were just laid directly onto the floorboards with the floor joists running at 90° to them, one central wall ran the whole width of the property and was supporting the undersized IPN holding up the 2nd floor and roof.


    • This reply was modified 23 Aug 2017 16:21 by  Chanceux.
    #1792181
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    mikej
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    Joined: 21 Jun 2011
    Location: Dordogne sometimes and Kent the rest
    Total posts: 5287

    Do not under any circumstances’ let the clay under that wall dry out, it will crack, shrink and eventually lead to destabilisation of the wall, IMO the way forward is to contain the clay with a vertical wall, similar to Chancer’s suggestion, but due to this being in a narrow hallway a little less obtrusive, I would suggest taking up the floor and casting an L shape 75/100mm concrete footing and retaining wall, with metal mesh reinforcement from the wall into the footing, this will need an impermeable barrier between it and the clay wall and sub-structure, this should direct any excess moisture towards the already damp cellar, whilst retaining the stable clay under the external wall, the height of the internal concrete wall needs to be at a minimum 150mm above the external ground level.

    Any make up required under the existing floor to minimise the amount of concrete required in the footing, should be a gravel/hardcore bed with a sand blinding to protect the impermeable barrier, keep the top of the footing low enough to allow tiling or reinstatement of the wooden floor on battens let into the footing.

    Mike


    WFIPFLL

    • This reply was modified 24 Aug 2017 11:16 by  mikej.
French Electrical & Other Building Issues
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